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elli.com/Abstracts_CIMT_NeuPlast_Rehab.html
***CIMT <=
/b>(constraint induced movement therapy; forced use=
)
Top Stroke =
Rehabil.
2001 Autumn;8(3):16-30.
Constraint-induced therapy ap=
proach
to restoring function after neurological injury.
Morris DM, Taub E.
Department of Physical Therapy, =
&n=
bsp; Traditional
rehabilitation programs for persons with neurologic dysfunction emphasize a
compensation, true recovery, or substitution approach to improve functional
abilities. Constraint-induced (CI) movement therapy substantially increases
more-affected extremity use in the life situation due to the influence of t=
wo
different underlying mechanisms: overcoming learned nonuse and inducing
use-dependent cortical reorganization. In this way, it bypasses the debate =
over
whether a compensation, true recovery, or substitution approach should be u=
sed.
The purposes of this article are to describe the CI therapy approach, discu=
ss
its proposed modes of action, and discuss other unique aspects of CI therap=
y as
a rehabilitation technique.
The Journal of Head Trauma Rehabilitation, May-June =
2003
v18 i3 p259(9)
Constraint-induced movement therapy for hemiplegic children with acquired brain injuries. (Focus
on Clinical Research and Practice). N. Karman; =
J. Maryles; R.W. Baker; E. Simpser<=
/span>;
P. Berger-Gross.
&n=
bsp; Objective:
To evaluate the feasibility and efficacy of constraint-induced movement the=
rapy
(CIMT) for impaired upper extremity (UE) function in children with acquired
brain injury (ABI). Design: Multiple case studies. Setting: Inpatient pedia=
tric
rehabilitation. Participants: Seven consecutive ABI rehabilitation admissio=
ns with
hemiparesis were recruited without regard to in=
jury
etiology, age, or cognitive capacities. Main Outcome Measure: The actual am=
ount
of use test (AAUT) was used to evaluate change in UE function. AAUT amount =
of
use (AOU) and quality of movement (
Neurology. 2003 Sep 23
Motor-improvement following i=
ntensive
training in low-functioning chronic hemiparesis=
.
Sterr A, Freivogel
S. asterr@liverpool.ac.=
uk
&n=
bsp; Constraint-induced
movement therapy can improve chronic hemiparesis, but
this technique has proven difficult to transfer into clinical practice. The
authors studied the benefits of a modified regimen designed to be applicabl=
e in
the clinical environment. Affected arm movements were trained for 90 min/d =
for
3 weeks using the learning principle "shaping." The outcome measu=
res
indicated a significant increase in performance after the intervention comp=
ared
with the performance during the 3-week baseline interval.
Phys Ther. 2003 Nov;83(11):1003-13.
Pediatric constraint-induced movement therapy for=
a
young child with cerebral palsy: two episodes of care.
sdeluca@uab.edu
BACKGROUND AND PURPOSE: This case report describes t=
he use
of "Pediatric Constraint-Induced Therapy (Pediatric CI Therapy)"
given on 2 separate occasions for a young child with q=
uadriparetic
cerebral palsy. CASE DESCRIPTION: The child was 15 months of age at the
beginning of the first episode of care. She had previously received weekly
physical therapy and occupational therapy for 11 months, but she had no
functional use of her right upper extremity (UE), independently or in an
assistive manner. She scored from 5 to 7 months below her chronological age=
on
developmental assessments in gross motor, fine motor, and self-help skills.
INTERVENTION: Pediatric CI Therapy involved placement of a full-arm, bivalved cast on the child's less affected UE while
providing 3 weeks of intensive intervention (6 hours a day) for the child's
more affected UE (intervention 1). Therapy included activities that were go=
al
oriented but broken down into progressively more challenging step-by-step
tasks. Pediatric CI Therapy was administered again 5 months later to promot=
e UE
skills and independence (intervention 2). OUTCOMES: The child developed new
behaviors throughout both interventions. During intervention 1, the child
developed independent reach, grasp, release, weight bearing (positioned pro=
ne
on elbows) of both UEs,
gestures, self-feeding, sitting, and increased interactive play using both =
UEs. During intervention 2, she had increased indepen=
dence
and improved quality of UE movement, as supported by blinded clinical
evaluations and parent ratings.
Pediatrics. 2004 Feb;113=
span>(2):305-12.
Efficacy of constraint-induced movement therapy f=
or
children with cerebral palsy
with asymmetric=
motor
impairment.
Taub E, Ramey SL, DeLuca S, Echols K.
Department of Psychology,
&n=
bsp; OBJECTIVE:
Constraint-Induced Movement (CI) therapy has been found to be a promising
treatment for substantially increasing the use of extremities affected by s=
uch
neurologic injuries as stroke and traumatic brain injury in adults. The pur=
pose
of this study was to determine the applicability of this intervention to yo=
ung
children with cerebral palsy. METHODS: A randomized, controlled clinical tr=
ial
of pediatric CI therapy in which 18 children with diagnosed hemiparesis
associated with cerebral palsy (7-96 months old) were randomly assigned to
receive either pediatric CI therapy or conventional treatment. Pediatric CI
therapy involved promoting increased use of the more-affected arm and hand =
by
intensive training (using shaping) of the more-impaired upper extremity for=
6
hours/day for 21 consecutive days coupled with bivalve=
d
casting of the child's less-affected upper extremity for that period. Children's functional upper-extremity skills were assessed in=
the
laboratory (blinded scoring) and at home (parent ratings) just prior, after,
and 3 weeks posttreatment. Treated child=
ren
were followed for 6 months. RESULTS: Children receiving pediatric CI therapy
compared with controls acquired significantly more new classes of motoric skills (9.3 vs 2.=
2);
demonstrated significant gains in the mean amount (2.1 vs
0.1) and quality (1.7 vs 0.3) of more-affected =
arm
use at home; and in a laboratory motor function test displayed substantial
improvement including increases in unprompted use of the more-affected upper
extremity (52.1% vs 2.1% of items). Benefits we=
re
maintained over 6 months, with supplemental evidence of quality-of-life cha=
nges
for many children. CONCLUSION: Pediatric CI therapy produced major and
sustained improvement in motoric function in the
young children with hemiparesis in the study.=
b>
Phys Ther. 2003 Nov;83(11):1003-13.
Pediatric constraint-induced movement therapy for=
a
young child with cerebral palsy: two episodes of care.
&n=
bsp; BACKGROUND
AND PURPOSE: This case report describes the use of "Pediatric
Constraint-Induced Therapy (Pediatric CI Therapy)" given on 2 separate
occasions for a young child with quadriparetic
cerebral palsy. CASE DESCRIPTION: The child was 15 months of age at the
beginning of the first episode of care. She had previously received weekly
physical therapy and occupational therapy for 11 months, but she had no
functional use of her right upper extremity (UE), independently or in an
assistive manner. She scored from 5 to 7 months below her chronological age=
on
developmental assessments in gross motor, fine motor, and self-help skills.
INTERVENTION: Pediatric CI Therapy involved placement of a full-arm, bivalved cast on the child's less affected UE while
providing 3 weeks of intensive intervention (6 hours a day) for the child's
more affected UE (intervention 1). Therapy included activities that were go=
al
oriented but broken down into progressively more challenging step-by-step
tasks. Pediatric CI Therapy was administered again 5 months later to promot=
e UE
skills and independence (intervention 2). OUTCOMES: The child developed =
new
behaviors throughout both interventions. During intervention 1, the chi=
ld
developed independent reach, grasp, release, weight bearing (positioned pro=
ne
on elbows) of both UEs,
gestures, self-feeding, sitting, and increased interactive play using both =
UEs. During intervention 2, she had increased indepen=
dence
and improved quality of UE movement, as supported by blinded clinical
evaluations and parent ratings.
Dev Med Child Neurol. 2003 May;45(5):357-9.
'Clinical experience of constraint induced moveme=
nt
therapy in adolescents with hemiplegic cerebral
palsy--a day camp model'.
Eliasson AC, Bonnier B, =
Krumlinde-Sundholm L.
Nervenarzt<=
/span>. 2003 A=
pr;74(4):334-42. =
[New developments in stroke rehabilitation based =
on
behavioral and neuroscientific principles:
constraint-induced therapy]
[Arti=
cle in
German]
Elber=
t T,
Rockstroh B, Bulach D, Meinzer M, Taub E. thomas.Elbert@uni-konstanz.de
&n=
bsp; Recent
discoveries about the central nervous system's response to injury and how
patients reacquire behavioral capabilities by training have yielded promisi=
ng
new therapies for neurorehabilitation. This fam=
ily of
interventions is termed constraint-induced (CI) therapy and is essentially
behavioral in nature. Constraining movement of the arm which is less affect=
ed
by the stroke and training (by shaping) the more affected arm for many hour=
s a
day for two consecutive weeks proved effective in the treatment of hemiplegia in many studies. Successful applications o=
ther
than for stroke have been for traumatic brain injury, cerebral palsy, spinal
cord injury, fractured hip, and focal hand dystonia.
Extending the principles to other consequences of stroke such as aphasia is
examined. Constraint-induced therapy is shown to produce large changes in t=
he
organization and function of the brain,which
emphasizes the significance of cortical reorganization and learning for
Stroke. 2003 Apr;34(4):1021-6.
Epub 2003 Mar 20.
Constraint-induced movement therapy and rehabilit=
ation
exercises lessen motor deficits and volume of brain injury after striatal hemorrhagic stroke in rats.
DeBow SB, Davies ML, Cla=
rke HL, Colbourne F.
&n=
bsp; BACKGROUND
AND PURPOSE: Constraint-induced movement therapy (CIMT) promotes motor reco=
very
after occlusive stroke in humans, but its efficacy after intracerebral
hemorrhage (ICH) has not been investigated clinically or in the laboratory.=
In
this study we tested whether CIMT and a rehabilitation exercise program wou=
ld
lessen motor deficits after ICH in rats. METHODS: Rats were subjected to striatal ICH (via infusion of co=
llagenase)
or sham stroke. Seven days later, treatment began with CIMT (8 h/d of ipsilateral forelimb restraint), rehabilitation exerc=
ises (eg, reaching, walking; 1 h/d), or both for 7 days. So=
me
rats were not treated. Motor deficits were assessed up to the 60-day surviv=
al
time, after which the volume of tissue lost was determined. RESULTS: Untrea=
ted
ICH rats made more limb slips traversing a horizontal ladder and showed an
asymmetry toward less use of the contralateral =
paw in
the cylinder test of limb use asymmetry (day 28). These rats were also
significantly less successful in the Montoya staircase test (days 55 to 59)=
of
skilled reaching. Neither therapy alone provided much benefit. However, the
combination of daily exercises and CIMT substantially and persistently impr=
oved
recovery. Unexpectedly, this group had a statistically smaller volume of ti=
ssue
lost than untreated ICH rats. CONCLUSIONS: The combination of focused
rehabilitation exercises and CIMT effectively promotes functional recovery
after ICH, while either therapy alone is less effective. This therapy may w=
ork
in part by reducing the volume of tissue lost, likely through reducing atro=
phy
while promoting remodeling.
Neurorehabi=
l Neural Repair.
2003 Mar;17(1):48-57.
Erratum in:
=
Neurorehabil
Neural Repair. 2003 Sep;17(3):197.
Constraint-induced therapy in stroke:
magnetic-stimulation motor maps and cerebral activation.
Witte=
nberg GF,
Chen R, Ishii K, Bushara KO, Eckloff S, Croarkin E, Taub E, Gerber LH, Hall=
ett
M, Cohen LG.
&=
nbsp; Constraint-induced
movement therapy (CI), a standardized intensive rehabilitation intervention,
was given to patients a year or more following stroke. The goal was to
determine if CI was more effective than a less-intensive control interventi=
on
in changing motor function and/or brain physiology and to gain insight into=
the
mechanisms underlying this recovery process. Subjects were recruited and
randomized more than 1 year after a single subcortical=
infarction. Clinical assessments performed before and after the intervention
and at 6 months
postinterve=
ntion
included the Wolf Motor Function Test (WMFT), the Motor Activity Log (MAL),=
and
the Assessment of Motor and Process Skills (AMPS). Tra=
nscranial
magnetic stimulation was used to map the motor cortex. Positron emission
tomography was used to measure changes in motor task-related activation due=
to
the intervention. MAL increased by 1.08 after CI therapy and decreased by 0=
.01
after control therapy. The difference between groups was significant (P <
0.001). Changes in WMFT and AMPS were not significantly different between
groups. Cerebral activation during a motor task decreased significantly,=
and
motor map size increased in the affected hemisphere motor cortex in CI pati=
ents
but not in control patients. Both changes may reflect improved ability of u=
pper
motor neurons to produce movement.
Clin Rehabil.
2004 Feb;18(1):110-4. Related
Articles, Links
Constraint-induced movement therapy: time for a l=
ittle
restraint?
Siege=
rt RJ,
Lord S, Porter K. rsiegert@wnmeds.ac.nz
Our aim was to
consider some issues surrounding constraint-induced movement therapy (CIMT),
and in particular, its theoretical basis, effectiveness, utility and
composition. We examined selected articles and related publications concern=
ing
CIMT. Considerable evidence from case studies and case series has accumulat=
ed
but only a limited number of randomized controlled trials (RCTs)
exist. The two most positive RCTs represent a
combined total of 15 people undergoing CIMT. Other issues include: how
analogous deafferentation of an upper limb in m=
onkeys
is to cerebral infarcts in humans; teasing out the active components of CIM=
T; a
need for replication by groups not already strongly associated with CIMT; a=
nd
patient/therapist acceptability. CIMT may hold considerable promise,=
but
independent, large-scale, multicentre RCTs comparing its effectiveness with conventional th=
erapy
of equal intensity are required, as is the consideration of some associated
issues.
Functional motor amnesia" in stroke (1904) a=
nd
"learned non-use phenomenon" (1966)
Jean-Marie André ;
Jean-Pierre Didier ; Jean Paysant
Journal of Rehabilitation Medicine 2004 May;36(3):138-40.
&n=
bsp; The
"learned non-use phenomenon" described by Ta=
ub,
one of the most original recent contributions to rehabilitation medicine
probably corresponds to what Henry Meige (1866-=
1940),
who studied under J.-M. Charcot, described in hemiplegics in 1904 using the expression
"functional motor amnesia". He specified in 1914 at the time of t=
he Babinski description of anosogno=
sia,
that: "Even with educated subjects who are still relatively young we a=
re
sometimes confronted with strange incapacities that are not due to impotenc=
e,
negligence, or lack of confidence in the results. [] With the transitory
halting of the motility all memory of the function appears to have
disappeared". Meige describes motor disord=
ers
that are: (i) distinct from lesional
paralyses; (ii) secondary to the absence of activity; (iii) linked to a
learning process; (iv) linked to a phenomenon of functional memory loss; (v)
reversible; and (vi) motor re-education focusing on extended and repeated
practice of the lost function: the same characteristics as the "phenom=
enon
of learned non-use" described by Taub in m=
onkeys
then in man.
Forced use after TBI: promoting plasticity and fu=
nction
through practice
Stephen Page
Source: Brain Injury Volume: 17
Number: 8 Page: 675 -- 684
Publisher:T=
aylor
& Francis Health Sciences
&n=
bsp; Abstract:
Objective: To review the literature supporting, and determine the efficacy =
of,
modified constraint-induced therapy (mCIT) in
improving more affected upper limb use and function in patients with trauma=
tic brain
injury (TBI). Design:
Multiple-baseline, pre-post, case series.&=
nbsp;
Setting: Outpatient clinic.
Patients: Three patients with TBI occurring >1 year ago and
exhibiting stable upper limb hemiparesis and le=
arned
non-use. Intervention: Patien=
ts
participated in 10 sessions of 30 minute, structured physical and occupatio=
nal
therapy, emphasizing more affected arm use in valued, functional activities,
three times/week for 10 weeks and using shaping techniques. Their less affe=
cted
upper limbs were also restrained 5 days/week during 5 hours identified as t=
imes
of frequent use during the same 10-week period. Main outcome measures: The A=
ction
Research Arm Test (ARA), Wolf Motor Function Test (WMFT) and Motor Activity=
Log
(MAL). Results: Following
intervention, subjects exhibited improvements > 2.0 in their amount and
quality of more affected limb use, as measured by the MAL. Subjects 1, 2 an=
d 3
also displayed functional improvements on the ARA (14.0, 5.5 and 6.0,
respectively), improvements in ratings of WMFT t=
ask
performance (1.15, 1.7 and 1.35, respectively) and diminished time needed to
perform all WMFT tasks.
Conclusions: mCIT is a promising approac=
h by
which improved more affected limb use and function can be realized following
TBI.
J Rehabil Med. 2004;36(4):159-164.
Addition of intensive repetition of facilitation
exercise to multidisciplinary rehabilitation promotes motor functional reco=
very
of the hemiplegic lower limb.
Kawahira K, Shimodozono
M, Ogata A, Tanaka N.
Department of Rehabilitation and=
Physical
Medicine, Faculty of Kagoshima
&n=
bsp; Objective:
To evaluate the effects of the intensive repetition of movements elicited by
the facilitation technique to improve voluntary movement of a hemiplegic lower limb in patients with brain damage.
Design: A multiple-baseline design (A-B-A-B: A without specific therapy, B =
with
specific therapy) across individuals. Patients: The sample comprised 22
subjects with stroke and 2 brain tumour-operated
subjects (age: 50.7 +/- 9.6 years, time after onset: 7.1 +/- 2.6 weeks). Th=
ey
were selected from among 165 patients with stroke who were admitted to our
rehabilitation centre from September 1, 1995 to March 31, 1997. Methods: Two
2-week facilitation technique sessions (more than 100 repetitions a day for
each of 5 kinds of movement) were applied at 2-week intervals in patients w=
ith hemiplegia, who were being treated with continuous
conventional rehabilitation exercise without the facilitation technique for=
hemiplegia. Motor function of the affected lower limb=
(Brunnstrom Recovery Stage of hem=
iplegia,
the foot-tap test and the strength of knee extension/flexion) and walking
velocity were evaluated at 2-week intervals. Results: Significant improveme=
nts
in Brunnstrom Stage, foot-tapping and the stren=
gth of
knee extension/flexion of the affected lower limb were seen after the first
conventional rehabilitation exercise session and after the first and second
facilitation technique and conventional rehabilitation exercise sessions. T=
he
improvements after facilitation technique and conventional rehabilitation
exercise sessions were significantly greater than those after the preceding
conventional rehabilitation exercise sessions. Conclusion: Intensive repeti=
tion
of movement elicited by the facilitation technique (chiefly proprioceptive
neuromuscural facilitation pattern, stretch ref=
lex
and skin-muscle reflex) improved voluntary movement of a hemiplegic
lower limb in patients with brain damage.
http://villamart=
elli.com/CIMT.html
CIMT END (contin=
ued in
Neural Plasticity)
***NEURAL PLASTI=
CITY
(overlaps with CIMT)
Neuroscientist. 2004 Apr<=
span
class=3DGramE>;10(2):129-41.
Reorganization of human cerebral cortex: the rang=
e of
changes following use and injury.
Elbert T, Rockstroh B.
&n=
bsp; Animal
and human research over the past decades have
increasingly detailed the brain's capacity for reorganization of neural net=
work
architecture to adapt to environmental needs. In this article, the authors
outline the range of reorganization of human representational cortex,
encompassing 1) reconstruction in concurrence with enhanced behaviorally
relevant afferent activity (examples include skilled musicians and blind
Braille readers); 2) injury-related response dynamics as, for instance, dri=
ven
by loss of input (examples include stroke, amputation, or in blind
individuals); and 3) maladaptive reorganization pushed by the interaction
between neuroplastic processes and aberrant
environmental requirements (examples include synchronicity of input nurturi=
ng
focal hand dystonia). These types of neuroplasticity have consequences for both understand=
ing
pathological dynamics and therapeutic options. This will be illustrated in
examples of motor and language rehabilitation after stroke, the treatment of
focal hand dystonia, and concomitants of
injury-related reorganization such as phantom limb pain.
Eur J Neurosci.
2004 Feb;19(4):1093-104.
Enhancement of steady-state auditory evoked magne=
tic
fields in tinnitus.
Diesch E, Struve
M, Rupp A, Ritter S, Hulse M, Flor
H. diesch@zi-mannheim.de
&n=
bsp; The
steady-state auditory evoked magnetic field and the Pb=
m,
the magnetic counterpart of the second frontocentrally=
positive middle latency component of the transitory auditory evoked potenti=
al,
were measured in ten tinnitus patients using a 122-channel gradiometer syst=
em.
The patients had varying degrees of hearing loss. In all patients, the tinn=
itus
frequency was located above the frequency of the audiometric edge, i.e. the
location on the frequency axis above which hearing loss increases more rapi=
dly.
Stimuli were amplitude-modulated sinusoids with carrier frequencies at the
tinnitus frequency, the audiometric edge, two frequencies below the audiome=
tric
edge, and two frequencies between the audiometric edge and the tinnitus
frequency. Below the audiometric edge, the root-mean-square field amplitude=
of
the steady-state response computed across the whole head as well as the
Behav Neurosci.
2004 Feb;118(1):214-22.
Coupling between "hand&q=
uot;
primary sensorimotor cortex and lower limb musc=
les
after ulnar nerve surgical transfer in parapleg=
ia.
Babiloni C, Vecchio
F, Babiloni F, Brunelli GA,
Carducci F, Cincotti F, Pizzella V, Romani GL, Tecchio FT, Rossini PM. claudio.=
babiloni@uniromal.it
&n=
bsp; Previous
neuroimaging evidence revealed an
"invasion" of "hand" over "lower limb" primar=
y sensorimotor cortex in paraplegic subjects, with the
exception of a rare patient who received a surgical motor reinnervation
of hip-thigh muscles by the ulnar nerve. Here, =
the
authors show that a functional reorganization of corti=
co-muscular
and cortico-cortical oscillatory coupling was r=
elated
to the recovery of the rare patient, as a paradigmatic case of long-term
plasticity in human sensorimotor cortex after m=
otor reinnervation of paraplegic muscles. This conclus=
ion
was based on electroencephalographic and electromyogra=
phic
data collected while the patient and normal control subjects performed
isometric muscle contraction of the left hand or lower limb. Cortico-muscular and cortico-cortical
coupling was estimated by electroencephalographic-elec=
tromyographic
coherence and directed transfer function of a multivariate autoregressive
model.
J Comput Neurosci. 2004 Mar-Apr;16<=
/span>(2):177-201.
A dynamical model of fast cor=
tical
reorganization.
Mazza M, de Pinho
M, Piqueira JR, Roque AC.
Departament=
o de Fisica e Matematica,
FFCLRP, Universidade de Sao Paulo,
&n=
bsp; In
this work we study the connection between some dynamic effects at the synap=
tic
level and fast reorganization of cortical sensory maps. By using a biologic=
ally
plausible computational model of the primary somatosen=
sory
system we obtained simulation results that can be used to relate the dynami=
cs
of the interactions of excitatory and inhibitory neurons to the process of =
somatotopic map reorganization immediately after peri=
pheral
lesion. The model consists of three regions integrated into a single struct=
ure:
tactile receptors representing the glabrous surface of the hand, ventral
posterior lateral nucleus of the thalamus and area 3b of the primary somatosensory cortex, reproducing the main aspects of=
the
connectivity of these regions. By applying informational measures to the
simulation results of the dynamic behavior of AMPA, NMDA and GABA synaptic =
conductances we draw some conjectures about how the s=
everal
neuronal synaptic elements are related to the initial stage of the
digit-induced reorganization of the hand map in the so=
matosensory
cortex.
NeuroRehabi=
litation. 2003;18(4):299-305.
Cortical remapping in amputees and dysmelic
patients: a functional MRI study.
Cruz =
VT, Nunes
B, Reis AM, Pereira JR. vcruz@hospitalfeira.min-saude.pt
&n=
bsp; OBJECTIVES:
To investigate motor cortex function in upper and lower limb amputees and <=
span
class=3DSpellE>dysmelic patients using fMRI.
MATERIAL AND METHODS: Five amputees and two dysmelic=
span>
patients were examined. Motor and imagery tasks were defined according to e=
ach
patient limb deficiency. Cortical activation patterns were analysed
for each patient and compared between groups, integrating patients
clinical data. RESULTS: There is a consistent pattern of cortical
reorganization in all amputees: predominance of activation in the ipsilateral motor cortex and extension to premotor and sensory areas of the contralateral
cortex. On the contrary, cortical maps of dysmelic
patients were similar to those of healthy volunteers, predominantly with
activation of contralateral primary motor cortex
areas. CONCLUSIONS: fMRI discloses sp=
ecific
patterns of cortical reorganization on amputees and dy=
smelic
patients, suggesting influence by prosthesis adaptation or stump use with
dexterity. These findings could be further applied in influencing neurorehabilitation and development of prosthetic dev=
ices.
Lakartidnin=
gen. 2003 Dec 18;100(51-52):42=
89-92.
[Rehabilitation after stroke.=
Imaging techniques show how the cortical reorganization is affected by
training] [Article in Swedish]
Lindb=
erg P,
Forssberg H, Borg J. <=
span
class=3DSpellE>pavel.lindberg@rehab.uu.se
&n=
bsp; It
is widely accepted that reorganisation of the b=
rain
occurs after a focal brain lesion such as stroke. Neur=
oimaging
methods are used to study such reorganisation in
vivo. Improvements in arm and hand motor function during recovery
post-stroke have been related to reorganisation=
in
primary and secondary sensorimotor areas by ind=
irect
measure of synaptic activity with functional MRI. Reor=
ganisation
occurs in both the affected and the unaffected hemispheres. Preliminary
training studies post-stroke have shown correlations between improvements in
motor function and brain activity changes. Recent research findings are
reviewed herein. Further understanding of the neurobiological mechanism=
s of
post-stroke recovery will lead to development of optimal treatment strategi=
es
during rehabilitation of stroke survivors.
J Neurol Sci.
2004 Mar 15;218(1-2):9-15.
Functional imaging during cov=
ert
auditory attention in multiple sclerosis.
Santa Maria MP, Benedict RH, Ba=
kshi
R, Coad ML, Wack D,=
Burkard R, Weinstock-Guttman B,
Roberts S, Lockwood AH.
&n=
bsp; Recent
literature suggests that the brain in multiple sclerosis (MS) undergoes
reorganization that subserves the performance of
visual and motor tasks. We identified sites of cerebral activity in 16 MS p=
atients
while performing a covert attention (CA) task, presented in the auditory
modality. Positron emission tomography (PET) revealed activation of rostral/dorsal anterior cingulat=
e
cortex (ACC) in normal subjects studied previously. Activity in this region=
was
not significant in MS patients, but there was a large region of activity in
superior temporal cortex. Decreased activation of frontal attentional
networks and greater activity in sensory/perceptual cortical areas (auditory
association cortex) suggests a reduction of transmission along white matter
tracts connecting these regions. This study demonstrates cingulate
hypoactivity and cerebral reorganization during
auditory attention in MS.
J Neuroimag=
ing.
2004 Jan;14(1):49-53.
Cortical reorganization allows for motor recovery=
after
crossed cerebrocerebellar atrophy.
Feydy A, Krainik
A, Bussel B, Maier MA.
Services d'=
Imagerie
Medicale, INSERM U483,
&n=
bsp; The
authors report the case of a 33-year-old woman who exhibited, at the age of=
17,
a left-sided hemiplegia, which was followed by =
good
motor recovery, though with a permanent deficit in fine finger movements. S=
he
had a widespread loss of neural tissue in the right hemisphere (crossed
Clin Neurophysiol.
2004 Feb;115(2):435-47.
Is there training-dependent reorganization of dig=
it
representations in area 3b of string players?
Hashimoto I, Suzuki A, Kimura T, Iguchi Y, Tanosaki M, Takino R,
ihashi@ael.kanazawa-it.ac.jp
&n=
bsp; OBJECTIVE:
The digit representations in area 3b were studied to examine whether there =
is
training-dependent reorganization in string players. METHODS: Somatosensory evoked magnetic fields were recorded
following electrical stimulation of digits 1 (D1), 2 (D2) and 5 (D5) of both
hands in 8 string players and of the left hand in 12 control subjects. The =
N20m
and P30m responses, and high-frequency oscillati=
ons (HFOs) were separated by 3-300 Hz and 300-900 Hz bandpass filtering. RESULTS: The dipole locations on =
the
coronal plane and strengths of D1, D2 and D5, and D1-D5 cortical distance
estimated at the
J Neurosci<=
/span>.
2004 Jan 14;24(2):442-6.
Improvement and decline in tactile discrimination
behavior after cortical plasticity induced by passive tactile coactivation.
Hodzic A, Veit
R, Karim AA, Erb M,=
Godde B.
Institute of Medical Psychology =
and
Behavioral Neurobiology,
&n=
bsp; Perceptual
learning can be induced by passive tactile coactivatio=
n
without attention or reinforcement. We used functional MRI (fMRI)
and psychophysics to investigate in detail the specificity of this type of
learning for different tactile discrimination tasks and the underlying cort=
ical
reorganization. We found that a few hours of Hebbian=
span> coactivation evoked a significant increase of primary=
(SI)
and secondary (SII) somatosensory cortical areas
representing the stimulated body parts. The amount of plastic changes was
strongly correlated with improvement in spatial discrimination performance.
However, in the same subjects, frequency discrimination was impaired after =
coactivation, indicating that even maladaptive proces=
ses
can be induced by intense passive sensory stimulation.
Neurology. 2003 Dec 23
Patterns of cortical reorgani=
zation
in complex regional pain syndrome.
Maiho=
fner C,
Handwerker HO, Neundorfer B, Birklein F.
maihoefner@physiologie1.uni-erlangen.de
&=
nbsp; OBJECTIVE:
To use magnetoencephalography to assess possible
cortical reorganization in the primary somatosensory=
span>
cortex (S1) of patients with complex regional pain syndrome (CRPS). BACKGRO=
UND:
Patterns of pain and sensory symptoms in CRPS may indicate plastic changes =
of
the CNS. METHODS: Magnetic source imaging was used to explore changes in the
cortical representation of digits (D) 1 and 5 in relation to the lower lip =
on
the unaffected and affected CRPS side in 12 patients. RESULTS: The authors
found a significant shrinkage of the extension of the cortical hand
representation for the CRPS affected side. The center of the hand was shift=
ed
toward the cortical representation of the lip. The cortical reorganization
correlated with the amount of CRPS pain (r =3D 0.792), as measured by the M=
cGill
questionnaire, and the extent of mechanical hyperalges=
ia
(r =3D 0.860). Using multiple regression analysis, the best predictor for t=
he
plastic changes was found to be mechanical hyperalgesi=
a.
Additionally, S1 sources following tactile stimulation were significantly
increased on the CRPS side compared to the unaffected limb. CONCLUSIONS: This
study showed reorganization of the S1 cortex contralat=
eral
to the CRPS affected side. The reorganization appeared to be linked to
complaints of neuropathic pain. Neuroimage<=
/span>. 2003 Dec;20(4):2166-80. Correlation between cerebral
reorganization and motor recovery after subcortical
infarcts. Loubinoux I, Carel
C, Pariente J, Dechaumont<=
/span>
S, Albucher JF, Marque P, Manelfe C, Chollet F. Isabelle.Loubinoux@toulouse.inserm.fr &n=
bsp; Our
objective was to investigate correlations between clinical motor scores and
cerebral sensorimotor activation to demonstrate=
that
this reorganization is the neural substratum of motor recovery. Correlation
analyses identified reorganization processes shared by all patients. Nine
patients with first-time corticospinal tract la=
cuna
were clinically evaluated using the NIH stroke scale, the motricity
index, and the Barthel index. Patients were str=
ictly
selected for pure motor deficits. They underwent a first fMRI
session (E1) 11 days after stroke, and then a second (E2) 4 weeks later. The
task used was a calibrated repetitive passive flexion/extension of the pare=
tic
wrist. The control task was rest. Six healthy subjects followed the same
protocol. Patients were also clinically evaluated 4 and 12 months after str=
oke.
All patients improved significantly between E1 and E2. For E1 and E2, the <=
span
class=3DSpellE>ipsilesionalipsilesional superior BA 40. Magnitude of activation =
was
lower than that of controls except for well-recovered patients. E1 clinical
hand motor score and E1 cerebral activation correlated in the SMA proper an=
d inferior
ipsilesional BA 40. Thus, we demonstrated ea=
rly
functionality of the sensorimotor system. The w=
hole sensorimotor network activation correlated with motor
status at E2, indicating a recovery of its function when activated. Moreove=
r,
the activation pattern in the acute phase (E1) had a predictive value: early
recruitment and high activation of the SMA and inferior BA 40 were correlat=
ed
with a faster or better motor recovery. On the contrary, activation of the =
contralesional hemisphere (prefrontal cortex and BA 3=
9-40)
and of the posterior cingulate/precuneus (BA 7-=
31)
predicted a slower recovery.
Top Stroke =
Rehabil.
2003 Fall;10(3):1-20.
Brain reorganization after st=
roke.
Green JB.
&n=
bsp; After
a stroke, recovery that continues beyond 3 or 4 weeks has been attributed to
plasticity, a reorganization of the brain in which functions previously
performed by the ischemic area are assumed by other ip=
silateral
or contralateral brain areas. Neuronal plastici=
ty has
been variously attributed to redundancy (parallel distributed pathways),
changes in synaptic strength, axonal sprouting with formation of new synaps=
es,
assumption of function by contralateral homolog=
ous
cortex, and substitution of uncrossed pathways. Transc=
ranial
magnetic stimulation, positron emission tomography (PET), functional magnet=
ic
resonance imaging (fMRI), and 128-electrode
high-resolution electroencephalography have been successfully applied to
demonstrate cortical reorganization after hemiplegia=
span>.
Recording the motor potential is a promising noninvasive method for the
localization of motor control after hemispheric lesions. Most patients with=
hemiparetic stroke show some improvement, usually dur=
ing
the first 3 to 6 months after the ictus. Improvement and prognosis depend o=
n a
number of variables including volume and location of the infarction, age of=
the
patient, and the elimination of risk factors to avoid future episodes (i.e.,
dietary control of lipids, the elimination of tobacco, and the control of
diabetes and hypertension). Currently, emphasis has been placed on fibrinolytic treatment in the first 3 hours to preven=
t or
minimize neurological deficit. Aside from the above listed factors, impr=
ovement
after stroke may be due to reorganization of the brain, particularly the
cerebral cortex, and repair of damaged tissue and reca=
nalization.
It is also important to relate such changes to functional improvement and
successful rehabilitation.
Neuroscientist. 2003 Dec<=
span
class=3DGramE>;9(6):463-74.
Properties and mechanisms of =
LTP
maintenance.
Abraham WC, Williams JM. cabraham@psy.otago.ac.nz
&n=
bsp; Memory
is fundamentally important to everyday life, and memory loss has devastating
consequences to individuals and society. Understanding the neurophysiological
and cellular basis of memory paves the way for gaining insights into the
molecular steps involved in memory formation, thereby revealing potential
therapeutic targets for neurological diseases. For three decades, long-term=
potentiation (LTP) has been the gold standard synaptic
model for mammalian memory mechanisms, in large part because of its
long-lasting nature. Here, the authors summarize the characteristics of LTP
persistence in the dentate gyrus of the hippoca=
mpus,
comparing this with other hippocampal subregions and neocortex.=
They
consider how long LTP can last and how its persistence is affected by
subsequent behavioral experiences. Next, they review the molecular mechanis=
ms
known to contribute to LTP induction and persistence, in particular the rol=
e of
new gene expression and protein synthesis and how they may be associated wi=
th
potential structural reorganization of the synapse. A temporal schema for t=
he
processes important for consolidating LTP into a persistent form is present=
ed. The
parallels between the molecular aspects of LTP and memory strongly support =
the
continuation with LTP as a model system for studying the mechanisms underly=
ing
long-term memory consolidation and retention.
Suppl Clin
Neurophysiol. 2003;56:358=
span>-67.
Modulation of sensorimotor=
span>
performances and cognition abilities induced by RPMS: clinical and experime=
ntal
investigations.
Struppler=
span> A, Angerer B, Havel
P. struppler@lrz.tum.de
&n=
bsp; The
investigations presented in this chapter lead to the conclusion that proprioceptive afferent inflow to the CNS induced by =
RPMS
elicits various modulatory effects in sensorimotor and cognitive systems. Since the build-u=
p of
the conditioning effects is delayed and the effects itself are long-lasting=
, it
has to be assumed that these effects are caused via ne=
uromodulators.
Therefore, the presented approach is promising to improve sensorimotor
and cognitive disturbances after lesions in the CNS, e.g. after a stroke, by
facilitation of reorganization.
Anasthesiol Intensivmed
Notfallmed Schmerzther.
2003 Dec;38(12):762-6.
[Phantom limb pain: aspects of neuroplasticity
and intervention] [Article in German]
Gruss=
er SM,
Diers M, Flor H.
&=
nbsp; Phantom-limb
pain is a common sequel of amputation, occurring in up to 80 % of the amput=
ee
population. It must be differentiated from non-painful phantom phenomena,
residual-limb pain, and non-painful residual-limb phenomena. A comprehensive
model of phantom-limb pain is presented that assigns a major role to pain
occurring before the amputation and to central as well as peripheral changes
related to it. Special emphasis is put on the role of cortical
reorganization in the development of phantom limb pain. Finally, new approa=
ches
to the prevention and treatment of phantom limb pain are presented that hav=
e a
positive influence on phantom limb pain by preventing or reversing cortical
reorganization.
Prog Brain Res. 2004;143:467-75.
Functional recovery after les=
ions of
the primary motor cortex.
Rouiller EM, Olivier E.<=
span
style=3D'mso-spacerun:yes'> eric.rouiller@unifr.ch
&n=
bsp; After
a lesion in the motor cortex of an adult primate, are cortical motor maps
reorganized? This important question has attracted much interest throughout=
the
past decade. In human subjects, substantial progress has resulted from the =
use
of noninvasive imaging and stimulation techniques. For example, there is
recent, well-accepted, albeit indirect evidence that following such a lesio=
n on
one side of the human brain, a dramatic reorganization of the hand
representation occurs within either the ipsilateral primary
motor cortex, nonprimary motor areas or both. T=
he
contribution of contralateral motor areas to
functional recovery of the paretic hand remains uncertain, however, because=
of
the lack of direct confirmatory evidence obtained from experiments undertak=
en
on nonhuman primates. A better understanding of how the brain selects the
optimal strategy for functional recovery following cortical lesions, and the
neuronal mechanisms underlying cortical plasticity, will be important
challenges for the next decade. To this end, the purpose of the present cha=
pter
is to provide an update on what is truly known about the functional recovery
that takes place after a lesion in the primary motor cortex of both the
nonhuman primate and the human. It bears emphasis that work on these
fundamental issues is an essential prerequisite to the development of impro=
ved
therapeutic and rehabilitation procedures for the brain-injured human.
Clin Neurophysiol.
2003 Dec;114(12):2434-46.
Plasticity of the human motor system following mu=
scle
reconstruction: a magnetic stimulation and functional magnetic resonance
imaging study.
Chen R, Anastakis DJ, Ha=
ywood
CT, Mikulis DJ, Manktelow<=
/span>
RT. robert.chen@uhn.on.ca
&n=
bsp; OBJECTIVE:
Although motor system plasticity in response to neuromuscular injury has be=
en
documented, few studies have examined recovered and functioning muscles in =
the
human. We examined brain changes in a group of patients who had a muscle
transfer. METHODS: Transcranial magnetic stimul=
ation
(TMS) was used to study a unique group of 9 patients who had upper extremity
motor function restored using microneurovascular
transfer of the gracilis muscle. The findings f=
rom
the reconstructed muscle were compared to the homologous muscle of the inta=
ct
arm. One patient was also studied with functional magnetic resonance imagin=
g (fMRI). RESULTS: TMS showed that the motor threshold a=
nd
short interval intracortical inhibition was red=
uced
on the transplanted side while at rest but not during muscle activation. The
difference in motor threshold decreased with the time since surgery. TMS
mapping showed no significant difference in the location and size of the
representation of the reconstructed muscle in the motor cortex compared to =
the
intact side. In one patient with reconstructed biceps muscle innervated by =
the intercostal nerves, both TMS mapping and fMRI showed that the upper limb area rather than the =
trunk
area of the motor cortex controlled the reconstructed muscle. CONCLUSIONS: =
Plasticity
occurs in cortical areas projecting to functionally relevant muscles. Chang=
es
in the neuronal level are not necessarily accompanied by changes in motor
representation. Brain reorganization may involve multiple processes mediate=
d by
different mechanisms and continues to evolve long after the initial injury<=
/b>.
SIGNIFICANCE: Central nervous system plasticity following neuromuscular inj=
ury
may have functional relevance.
Neurology. 2003 Oct 14
Plasticity of motor cortex
excitability induced by rehabilitation therapy for writing.
Papathanassiou I, Filipovic SR, Whurr R, Jahanshahi M.
&n=
bsp; The
mechanisms of rehabilitation-induced plasticity in the motor system after
stroke are not defined. The authors studied seven patients with residual poststroke agraphia, apha=
sia, and
right hemiparesis. After a 40-minute rehabilita=
tion
therapy that promoted use of the paretic hand for writing, the authors obse=
rved
a task-specific increase in recruitment of ipsilateral=
corticospinal pathways. Rehabilitation aimed to
increase the use of the paretic hand may induce recruitment of previously
silent ipsilateral cortico=
spinal
pathways even in poorly recovered poststroke
patients.
In Press.
Behavioural Brain Resear=
ch
Consequences of forced disuse of the impaired for=
elimb
after unilateral cortical injury
J. Leigh Leasure, and Ti=
mothy Schallert
&n=
bsp; Extreme
over-reliance on the impaired forelimb following unilateral lesions of the
forelimb representation area of the rat sensorimotor=
span>
cortex (FL-SMC) leads to exaggeration of injury when overuse is begun durin=
g the
first week, but not later periods, after injury. Behavioral impairment is
partially worsened by the additional tissue loss. In the present study, we =
show
that complete disuse of the impaired forelimb during the first post-operati=
ve
week renders surviving tissue vulnerable to later overuse of the same limb,=
in
effect extending the window of vulnerability in which use-dependent
exaggeration of brain injury can occur. Behavioral recovery is disrupted by
complete disuse, but the degree of impairment is variable depending on the
nature of the behavioral test employed. Our results uphold the idea that
mild rehabilitative training early after injury is beneficial, while either
extreme overuse or complete disuse may disrupt functional recovery.
Jul 2003, Vol. 26, pp. 411-440
MOLECULAR APPROACHES TO SPINAL CORD REPAIR
Samuel David and Steve Lacroix<=
/span>;
email: sdavid11@po-box.mcgill.ca; steve.lacroix@mail.mcgill.ca &n=
bsp; Axon
growth inhibitors associated with myelin and the glial=
scar contribute to the failure of axon regeneration in the injured adult
mammalian central nervous system (CNS). A number of these inhibitors, their
receptors, and signaling pathways have been identified. These inhibitors can
now be neutralized by a variety of approaches that point to the possibility=
of
developing new therapeutic strategies to stimulate regeneration after spinal
cord injury. Neuroscientist. 2004 Apr<=
span
class=3DGramE>;10
Plasticity in the human cerebral cortex: lessons =
from
the normal brain and from stroke.
Butefisch CM.
Neurological Therapeutic Center,
Department of Neurology,
&n=
bsp; The
adult brain maintains the ability for reorganization or plasticity througho=
ut
life. Results from neurophysiological and <=
span
class=3DSpellE>neuroanatomical experiments in animals and noninvasiv=
e neuroimaging and electrophysiological studies in huma=
ns
show considerable plasticity of motor representations with use or nonuse, s=
kill
learning, or injury to the nervous system. An important concept of
reorganization in the motor cortex is that of a distributed neuronal networ=
k in
which multiple overlapping motor representations are functionally connected
through an extensive horizontal network. By changing the strength of
horizontal connections between motor neurons, functionally different neuron=
al
assemblies can form, thereby providing a substrate to construct dynamic mot=
or
output zones. Modulation of inhibition and synaptic efficacy are mechanisms
involved. Recent evidence from animal experiments indicates that these
functional changes are accompanied by anatomical changes. Because plasti=
city
of the brain plays a major role in the recovery of function after stroke, t=
he
knowledge of the principles of plasticity may help to design strategies to
enhance plasticity when it is beneficial, such as after brain infarction.
Neuroplasticity:
Changes in grey matter induced by training
BOGDAN
DRAGANSKI*, CHRISTIAN GASER†, VOLKER BUSCH*, GERHARD SCHUIERER‡,
ULRICH BOGDAHN* & ARNE MAY*
Nature 427, 311 - 312 (22 January 2004)
&n=
bsp; Does
the structure of an adult human brain alter in response to environmental
demands? Here we use whole-brain magnetic-resonance imaging to visualize
learning-induced plasticity in the brains of volunteers who have learned to=
juggle.
We find that these individuals show a transient and selective structural ch=
ange
in brain areas that are associated with the processing and storage of compl=
ex
visual motion. This discovery of a stimulus-dependent alteration in the bra=
in's
macroscopic structure contradicts the traditionally held view that cortical
plasticity is associated with functional rather than anatomical changes.
Proc. Natl. Acad. Sci. U=
SA,
10.1073/pnas.0307840101
www.pnas.org/cgi/doi/10.1073/pnas.0307840101
Changes in corticothalamic=
span>
modulation of receptive fields during peripheral injury-induced reorganizat=
ion
S. A. Chowdhury, K. A. G=
reek,
and D. D. Rasmusson, E-mail: rasmus@dal.ca
&n=
bsp; The
influence of corticothalamic projections on the
thalamus during different stages of reorganization was determined in
anesthetized raccoons that had undergone previous removal of a single forep=
aw
digit. Single-unit recordings were made from 522 sites in the somatosensory nucleus of the thalamus (ventroposterior
lateral nucleus) before and after lesioning par=
ts of
primary somatosensory cortex. In those parts of=
ventroposterior lateral nucleus that had intact input=
from
the periphery, the cortical lesion resulted in an immediate 85% increase in
receptive field (RF) size. In animals studied 2-6 weeks after digit
amputation, peripherally denervated thalamic ne=
urons
had unique RFs that were larger than normal, and
these were not further enlarged by cortical lesion. However, at longer peri=
ods
of reorganization (>4 mo), when the new RFs =
of denervated neurons had decreased in size, cortical le=
sion
again produced expansion of RF size. These data demonstrate that corticothalamic fibers modulate the spatial extent of
thalamic RFs in intact animals, probably by
controlling intrathalamic inhibition. This corticothalamic modulation is ineffective during the =
early
stages of injury-induced reorganization when new RFs=
span>
are being formed, but is reinstated after the new RFs<=
/span>
have become stabilized. The fact that neurons in the denervated
thalamic region retained their unique RFs after
cortical lesion indicates that their new inputs are not being relayed from a
reorganized cortex and support the view that some plasticity occurs in or b=
elow
the thalamus.
Proc. Natl. Acad. Sci. U=
SA,
10.1073/pnas.0401200101
www.pnas.org/cgi/doi/10.1073/pnas.0401200101
Improving vision in adult am=
blyopia
by perceptual learning
Uri Polat=
span>, Tova Ma-Naim, Michael
&n=
bsp; Practicing
certain visual tasks leads, as a result of a process termed "perceptua=
l learning,"
to a significant improvement in performance. Learning is specific for basic
stimulus features such as local orientation, retinal location, and eye of
presentation, suggesting modification of neuronal processes at the primary
visual cortex in adults. It is not known, however, whether such low-level
learning affects higher-level visual tasks such as recognition. By
systematic low-level training of an adult visual system malfunctioning as a
result of abnormal development (leading to amblyopia=
span>)
of the primary visual cortex during the "critical period," we show
here that induction of low-level changes might yield significant perceptual
benefits that transfer to higher visual tasks. The training procedure resul=
ted
in a 2-fold improvement in contrast sensitivity and in letter-recognition
tasks. These findings demonstrate that perceptual learning can improve basic
representations within an adult visual system that did not develop during t=
he
critical period.
lin<=
/span> Rehabil. 2004 Feb;18(1):11=
0-4.
Constraint-induced movement therapy: time for a l=
ittle
restraint?
Siege=
rt RJ,
Lord S, Porter K. rsiegert@wnmeds.ac.nz
&n=
bsp; Our
aim was to consider some issues surrounding constraint-induced movement the=
rapy
(CIMT), and in particular, its theoretical basis, effectiveness, utility and
composition. We examined selected articles and related publications concern=
ing
CIMT. Considerable evidence from case studies and case series has accumulat=
ed
but only a limited number of randomized controlled trials (RCTs)
exist. The two most positive RCTs represent a
combined total of 15 people undergoing CIMT. Other issues include: how
analogous deafferentation of an upper limb in m=
onkeys
is to cerebral infarcts in humans; teasing out the active components of CIM=
T; a
need for replication by groups not already strongly associated with CIMT; a=
nd
patient/therapist acceptability. CIMT may hold considerable promise, but
independent, large-scale, multicentre RCTs comparing its effectiveness with conventional th=
erapy
of equal intensity are required, as is the consideration of some associated
issues.
Blocking activation of a death receptor enhances =
axonal
regeneration and functional recovery in an animal model of spinal cord inju=
ry
Catherine Barthélé=
;my;
Christopher E. Henderson
Nat Med 10(4):339-340, 2004
&n=
bsp; Spinal
cord injury will permanently handicap about 1 in 1,000 individuals over the
course of their lifetime.[1] Much effort has been
devoted to understanding the complex cellular changes that develop after
injury, and to inventing ways to overcome the poor capacity of the adult sp=
inal
cord for spontaneous regeneration.[2] Programmed cell death within the dama=
ged
tissue is one of these changes, but whether it hinders recovery has been
controversial.
&n=
bsp; In
this issue, Demjen et al.[<=
/span>3]
show that the death receptor CD95/Fas is a major trigger of cell death in t=
he
injured spinal cord. They find that mice treated with neutralizing antibodi=
es
to CD95/Fas recover from a spinal cord lesion that leaves untreated animals
heavily handicapped. This shows that keeping cells alive at the lesion site
promotes subsequent recovery, and provides a potential tool for doing so in
human patients.
&n=
bsp; Programmed
cell death is a tightly regulated process that can be initiated by diverse
stimuli, including extracellular signals acting=
at
specific receptors such as CD95/Fas and tumor necrosis factor (TNF)
receptor.[4] Both of these receptors have a predominant role in apoptosis
(hence the commonly used term 'death receptor'), but they can activate a
variety of other pathways and cellular phenomena.[5] In the nervous system,
CD95/Fas activation can lead to cell death of neurons[6] and glial cells,[7] but also to enhanced axonal growth.[8]
CD95/Fas may have an important role in pathological degeneration in vivo:
CD95/Fas and its ligand, CD95L/FasL, have been
implicated in cell death after nerve transection,[9]
ischemia,[10] amyotrophic lateral sclerosis,[11] multiple sclerosis, Parkin=
son
disease[12] and Alzheimer disease.
&n=
bsp; After
spinal cord injury in human patients and in animal models, some cells at the
lesion site die by post-traumatic necrosis, whereas others, including oligodendrocytes, die by apoptosis.[13] In line with =
this,
spinal cord trauma leads to increased expression of death receptors and the=
ir ligands, as well as to activation of death-promoting =
caspases.[14] Initial experiments showed that caspase inhibition has a protective effect in models =
of
spinal cord injury, providing the first indication that reducing cell death=
might
be beneficial.[15] Others, however, have observed no protection.[16] Further
uncertainty about the role of cell death arose when it was shown that
inactivation of TNF or its receptor did not improve prognosis.[17]
&n=
bsp; These
ambiguous results probably reflect the known capacity of TNF to be both pro-
and antiapoptotic. Demjen<=
/span>
et al. therefore asked instead whether a less ambivalent death receptor,
CD95/Fas, might be involved. They first confirmed that in their model, spin=
al
cord injury led to rapid upregulation of the
components of the CD95/Fas system and to increased apoptosis (measured as t=
he
number of neurons and oligodendrocytes with
fragmented nuclear DNA). Intraperito
&n=
bsp; A
true understanding of how antibodies to CD95/Fas reduce cell death and enha=
nce
recovery will require more detailed knowledge. The cellular source and targ=
et
of the ligand in damaged spinal cord need to be
identified, and the links between axonal sprouting and recovery of motor
function need to be defined.
&n=
bsp; Nonetheless,
the following model (Fig. 1) may apply: After injury, CD95L/FasL is upregulated at the lesion site on neurons, astrocytes and invading lymphocytes and microglia.
CD95L/FasL triggers death of oligodendrocytes a=
nd
local spinal interneurons, resulting in an
environment that is not favorable to regrowth of
descending corticospinal axons. Preventing cell=
death
provides an environment more conducive to spontaneous regeneration, and
formation of new circuits leads to functional recovery in voluntary motor
tests.
&n=
bsp; This
model may in some respects be reductionist. For
example, it ignores the possible role of autocrine
CD95/Fas activation, and possible effects of CD95L/FasL or the blocking
antibodies on more distant targets such as circulating lymphocytes or the <=
span
class=3DSpellE>corticospinal neurons themselves.
&n=
bsp; What
remains to be done before these findings can lead to tests in human patient=
s,
in parallel with the wide range of other strategies being developed? Several
differences with the clinical setting are apparent. First, the lesion used =
here
(surgical transection of the spinal cord) is qu=
ite
different from human cases of spinal cord injury, many of which result from
local compression. Second, for the behavioral experiments mice were treated
with antibodies immediately before injury. Clearly, protocols will need to =
be
developed to deliver antibodies to the lesion site within the human CNS at
later stages. Third, the oncogenic risks of blo=
cking
cell death cannot be ignored, although the authors point out that these ris=
ks
should be minor over short periods of treatment.
&n=
bsp; As
with other experimental strategies, many questions remain to be addressed. =
The
experimental paradigm of Demjen et al. is
particularly stringent, meaning that functional recovery may be greater in
other models. The new work thus firmly places a new actor on the list of
players in spinal cord repair.
Proc Nat Acad Sci | June 1, 2004 | vol. 101 | no. 22 | 8473-8478
Voluntary exercise increases axonal regeneration =
from
sensory neurons
Raffaella Molteni,
Jun-Qi Zheng, Zhe Ying, Fernando Gómez-=
Pinilla , and Jeffer=
y L. Twiss
Edited by Eric M. Shooter
&n=
bsp; Recent
advances in understanding the role of neurotrophins
on activity-dependent plasticity have provided insight into how behavior can
affect specific aspects of neuronal biology. We present evidence that
voluntary exercise can prime adult dorsal root ganglion neurons for increas=
ed
axonal regeneration through a neurotrophin-depe=
ndent
mechanism. Dorsal root ganglion neurons showed an increase in neurite outgrowth when cultured from animals that had
undergone 3 or 7 days of exercise compared with sedentary animals. Neurite length over 18–22 h in culture correlat=
ed
directly with the distance that animals ran. The exercise-conditioned anima=
ls
also showed enhanced regrowth of axons after an=
in
vivo nerve crush injury. Sensory ganglia from the 3- and 7-day-exercised
animals contained higher brain-derived neurotrophic
factor, neurotrophin 3, sy=
napsin
I, and GAP43 mRNA levels than those from sedentary animals. Consistent with=
the
rise in brain-derived neurotrophic factor and <=
span
class=3DSpellE>neurotrophin 3 during exercise, the increased grow=
th
potential of the exercise-conditioned animals required activation of the neurotrophin signaling in vivo during the exercise pe=
riod
but did not require new mRNA synthesis in culture.
Developmental Brain Research, Article in Press
Evidence of newly generated neurons in the human
olfactory bulb
Andréanne Bédard and André Parent,
&n=
bsp; The
subventricular zone (SVZ) is known to be the ma=
jor
source of neural stem cells in the adult brain. In rodents and nonhuman
primates, many neuroblasts generated in the SVZ
migrate in chains along the rostral migratory s=
tream
(RMS) to populate the olfactory bulb (glutamic acid decarboxylase
(GAD), a marker of GABAergic neurons, or tyrosi=
ne hydroxylase (TH), a marker of do=
paminergic
neurons. Other early committed neurons expressed the calcium-binding protei=
ns calretinin (CR) or parvalbumin=
span>
(PV). These results provide strong evidence for the existence of adult <=
span
class=3DSpellE>neurogenesis in the human olfactory system. Despite i=
ts
relatively small size compared to that in rodents and nonhuman primates, the
olfactory bulb in humans appears to be populated, throughout life, by new
granular and periglomerular neurons that expres=
s a
wide variety of chemical phenotypes.
Annual Review of Neuroscience
PLASTICITY OF THE SPINAL NEURAL CIRCUITRY AFTER I=
NJURY
V. Reggie Edgerton, Niranjala=
span>
J.K. Tillakaratne, Allison J. Bigbee,
Ray D. de Leon, and Roland R. Roy: vre@ucla.edu, nirat@lifesci.ucla.edu,
rrr@ucla.edu
&n=
bsp; Abstract
Motor function is severely disrupted following spinal cord injury (SCI). The
spinal circuitry, however, exhibits a great degree of =
automaticity
and plasticity after an injury. Automaticity im=
plies
that the spinal circuits have some capacity to perform complex motor tasks
following the disruption of supraspinal input, =
and evidence
for plasticity suggests that biochemical changes at the cellular level in t=
he
spinal cord can be induced in an activity-dependent manner that correlates =
with
sensorimotor recovery. These characteristics
should be strongly considered as advantageous in developing therapeutic
strategies to assist in the recovery of locomotor
function following SCI. Rehabilitative efforts combining locomotor training pharmacological means and/or spina=
l cord
electrical stimulation paradigms will most likely result in more effective
methods of recovery than using only one intervention.
=
Experimental Brain Research Issue: Volume 157, Numbe=
r 3
August 2004, 377 - 382
Recovery of forward stepping in spinal cord injur=
ed
patients does not transfer to untrained backward stepping
Renato Grasso,
Yuri P. Ivanenko, Myrka Zago, Marco Molinari, Gio=
rgio Scivoletto and Francesco Lacquan=
iti
&n=
bsp; Abstract Six
spinal cord injured (SCI) patients were trained to step on a treadmill with
body-weight support for 1.5–3 months. At the end of training, foot mo=
tion
recovered the shape and the step-by-step reproducibility that characterize
normal gait. They were then asked to step backward on the treadmill belt th=
at
moved in the opposite direction relative to standard forward training. In
contrast to healthy subjects, who can immediately reverse the direction of
walking by time-reversing the kinematic wavefor=
ms,
patients were unable to step backward. Similarly patients were unable to
perform another untrained locomotor task, namely
stepping in place on the idle treadmill. Two patients who were trained to s=
tep
backward for 2–3 weeks were able to develop control of foot motion
appropriate for this task. The results show that locom=
otor
improvement does not transfer to untrained tasks, thus supporting the idea =
of
task-dependent plasticity in human locomotor
J Geriatr Psychiatry 200=
4;
12:395–402
Cognitive Rehabilitation of Mildly Impaired Alzhe=
imer
Disease Patients on Cholinesterase Inhibitors
David A. Loewenstein, Ph.D., Amarilis
Acevedo, Ph.D. Sara J. Czaja, Ph.D., Ranjan Duara, M.D.
 =
; Objective:
The authors evaluated the efficacy of a new cognitive rehabilitation
program on memory and functional performance of mildly impaired Alzheimer
disease (AD) patients receiving a cholinesterase inhibitor. Methods: Twenty-five
participants in the Cognitive Rehabilitation (CR) condition participated in=
two
45-minute sessions twice per week for 24 total sessions. CR training includ=
ed
face– association tasks, object recall training, functional tasks (e.=
g.,
making change, paying bills), orientation to time and place, visuo-motor speed of processing ,=
and the use of a memory notebook. Nineteen participants in the Mental
Stimulation (MS) condition had equivalent therapist contact and number of
sessions, which consisted of interactive computer games involving memory,
concentration, and problem-solving skills. Results: Compared with th=
e MS
condition, participants in CR demonstrated improved performance on tasks th=
at
were similar to those used in training. Gains in recall of face–
associations, orientation, cognitive processing speed, and specific functio=
nal
tasks were present post-intervention and at a 3-month follow-up. Conclus=
ion:
A systematic program of cognitive rehabilitation can result in maintained
improvement in performance on specific cognitive
and functional =
tasks in
mildly impaired AD patients.
Top Stroke =
Rehabil.
2004 Spring;11(2):12-22.
Motor recovery strategies after stroke.
Stein J.
Hospital,
Impaired motor function after stroke is a major caus=
e of
disability in young stroke survivors. The plasticity of the adult human bra=
in
provides opportunities to enhance traditional rehabilitation programs for t=
hese
individuals. Younger stroke patients appear to have a greater ability to
recover from stroke and are likely to benefit substantially from treatments
that facilitate plasticity-mediated recovery. The use of new exercise
treatments, such as constraint-induced movement therapy, robot-aided
rehabilitation, and partial body weight supported treadmill training are be=
ing
studied intensively and are likely to ultimately be incorporated into stand=
ard poststroke rehabilitation. Medications to enhance rec=
overy,
growth factors, and stem cells will also be components of rehabilitation for
the young stroke survivor in the foreseeable future.
Title: Traumatic brain injury and its effects on syn=
aptic
plasticity
Author(s): Benedict C. Albensi ; Damir Janigro
Source: Brain Injury Volume: 17
Number: 8 Page: 653 -- 663
DOI: 10.1080/0269905031000107142
Publisher:T=
aylor
& Francis Health Sciences
Abstract: Animal models have been used to simulate t=
he
effects of human head trauma. Some of these models have been further utiliz=
ed
to explore how trauma affects specific mechanisms of synaptic plasticity, a
cellular model for memory consolidation. Unfortunately, these studies have =
been
more limited in number in spite of their importance for understanding
alterations in synaptic plasticity and memory impairments in trauma patient=
s.
Research in this area includes well characterized trauma models, genetically
engineered animals and neuroprotective studies.=
One
largely ignored but important idea that is entertained here is that trauma =
may
be a crucial aetiological factor for the loss of
potassium homeostasis. Moreover, high extracellular
potassium has been shown to promote abnormal expression of hippocampal
synaptic plasticity due to K+-induced glutamate release, thus showing impor=
tant
relationships among trauma, glia, potassium and
synaptic plasticity. Collectively, this mini review surveys investigations =
of
head trauma involving altered mechanisms of synaptic plasticity and how tra=
uma
may be related to increased risk for dementia.
Neuroplasticity
following non-penetrating traumatic brain injury
Author(s): Harvey S. Levin
Source: Brain Injury Volume: 17
Number: 8 Page: 665 -- 674
&n=
bsp; Abstract:
The primary objective of this review is to examine the methodology and evid=
ence
for neuroplasticity operating in recovery from
traumatic brain injury (TBI), as compared with previous findings in patients
sustaining perinatal and infantile focal vascul=
ar
lesions. The evidence to date indicates that the traditional view of enhanc=
ed
reorganization of function after early focal brain lesions might apply to e=
arly
focal brain lesions, but does not conform with studies of early severe diff=
use
brain injury. In contrast to early focal vascular lesions, young age confer=
s no
advantage in the outcome of severe diffuse brain injury. Disruption of myelination could potentially alter connectivity, a
suggestion which could be confirmed through diffusion tensor imaging (DTI).
Initial reports of DTI in TBI patients support the possibility that this
technique can demonstrate alterations in white matter connections which are=
not
seen on conventional magnetic resonance imaging (MRI) and might change over
time or with interventions. Preliminary functional MRI studies of TBI
patients indicate alterations in the pattern of brain activation, suggesting
recruitment of more extensive cortical regions to perform tasks which stress
computational resources. Functional MRI, coupled with DTI and possibly other
imaging modalities holds the promise of elucidating mechanisms of neuroplasticity and repair following TBI.
Title: Neuropharmacology=
of
TBI-induced plasticity
Author(s): Larry B. Goldstein
Source: Brain Injury Volume: 17
Number: 8 Page: 685 -- 694
DOI: 10.1080/0269905031000107179
Publisher:T=
aylor
& Francis Health Sciences
&n=
bsp; Abstract:
Primary objective: The purpose of this report is to review both fundamental
studies in laboratory animals and preliminary clinical data suggesting that
certain drugs may affect behavioural recovery a=
fter
brain injury. Main outcomes and results: Laboratory studies show that
systemically-administered drugs that affect specific central neurotransmitt=
ers
including norepinephrine and GABA influence aff=
ect
recovery in a predictable manner. Although some drugs such as d-amphetamine
have the potential to enhance recovery, others such as neuroleptics
and other central dopamine receptor antagonists, benzodiazepines and the an=
ti-convulsants phenytoin and=
phenobarbital may be detrimental. In one study=
, 72%
of patients with traumatic brain injury received one or a combination of the
drugs that may impair recovery based on both animal experiments and studies=
in
recovering stroke patients.
Conclusions: Until the true impact of these clas=
ses of
drugs are better understood, care should be exercised in the use of
medications that may interfere with the recovery process in patients with
traumatic brain injury. Additional research needs to be completed be=
fore
the clinical efficacy of drugs that may enhance recovery can be established=
.
Yonsei Med J. 2004 Apr 3=
0;45(2):241-6.
Plastic changes of motor netw=
ork
after constraint-induced movement therapy.
Kim Y=
H, Park JW,
Ko MH, Jang SH, Lee PK.
yunkim@smc.samsung.co.kr
&n=
bsp; The
effects of short-term constraint-induced movement (CIM) therapy on the
activation of the motor network were investigated with functional magnetic
resonance imaging (fMRI). Movement of the less-=
affected
arms of five patients was restricted and intensive training of the affected
upper limb was performed. Functional MRI was acquired before and after
two-weeks of CIM therapy. All patients showed significant improvement of mo=
tor
function in their paretic limbs after CIM therapy. For three patients, new
activation in the contralateral motor/premotor cortices was observed after CIM therapy. Inc=
reased
activation of the ipsilateral motor cortex and =
SMA
was observed in the other patient. Our results demonstrated that plastic
changes of the motor network occurred as a neural basis of the improvement
subsequent to CIM therapy following brain injury.
Taeha=
n Kanho
Hakhoe Chi. 2003 Aug;33(5):591-600.
[Effects of Upper Extremity Exercise Training Usi=
ng Biefeedback and Constraint-induced Movement on the Up=
per
Extremity Function of Hemiplegic Patients]<=
span
style=3D'mso-spacerun:yes'> [Article in Korean]
Kim K=
S, Kim KS,
Kang JY.
&n=
bsp; PURPOSE:
The purpose of this study was to investigate the effects of exercise traini=
ng
using biofeedback and constraint-induced movement on the upper extremity
function of hemiplegic patients. METHOD: A
non-equivalent pretest-posttest design was used. Study subjects were a
conveniently selected group of 40 hemiplegic patients(20 experimental subjects, 20 control subjects=
) who
have been enrolled in two community health centers. After biofeedback train=
ing
the subjects of experimental group were given constraint-induced movement,
involving restraint of unaffected U/E in a sling for about 6 hours in a day
over a period of two weeks, while at the same time intensively training the
affected U/E. Outcomes were evaluated on the basis of the U/E motor ability(hand function, grip power, pinch power, U/E RO=
Ms),
and motor activity(amount, quality). RESULT: 1. After 2 weeks of treatment,=
the
motor abilities of affected U/E(hand function, grip power, pinch power, ROM=
s of
wrist flexion, elbow flexion and shoulder flexion/extension) were significa=
ntly
higher in subjects who participated in exercise training than in subjects in
the control group with no decrement at 4-week follow-up. However, there was=
no
significant difference in wrist extension between experimental or control
group. 2. After 2 weeks of treatment, the amount of use and the quality of
motor activity of affected U/E were significantly higher in subjects who
participated in exercise training than in subjects in the control group wit=
h no
decrement at 4-week follow-up. CONCLUSION: The above results state that
exercise training using biofeedback and constraint-induced movement could b=
e an
effective intervention for improving U/E function of chronic hemiplegic patients. Long-term studies are needed to
determine the lasting effects of constraint-induced movement.
Neurorehabi=
l Neural Repair. 2004 Jun;18=
(2):95-105.
Changes in serial optical topography and TMS duri=
ng
task performance after constraint-induced movement therapy in stroke: a case
study.
Park SW,
&n=
bsp; The
authors examined serial changes in optical topography in a stroke patient
performing a functional task, as well as clinical and physiologic measures
while undergoing constraint-induced therapy (CIT). A 73-year-old right hemiparetic patient, who had a s=
ubcortical
stroke 4 months previously, received 2 weeks of CIT. During the therapy, da=
ily
optical topography imaging using near-infrared light was measured serially
while the participant performed a functional key-turning task. Clinical out=
come
measures included the Wolf Motor Function Test (WMFT), Motor Activity Log
(MAL), and functional key grip test. Transcranial
magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) were also used to map cortical areas and hemodynamic brain responses, respectively. Optical
topography measurement showed an overall decrease in oxy-hemoglobin
concentration in both hemispheres as therapy progressed and the laterality
index increased toward the contralateral hemisp=
here.
An increased TMS motor map area was observed in the co=
ntralateral
cortex following treatment. Posttreatment fMRI showed bilateral primary motor cortex activation,
although slightly greater in the contralateral
hemisphere, during affected hand movement. Clinical scores revealed mark=
ed
improvement in functional activities. In one patient who suffered a stroke,=
2
weeks of CIT led to improved function and cortical reorganization in the
hemisphere contralateral to the affected hand.<=
/b>
Arch Phys Med Rehabil.
2004 Jan;85(1):14-8.
Efficacy of modified constraint-induced movement =
therapy
in chronic stroke: a single-blinded randomized controlled trial.
Page SJ, Sisto S, Levine=
P,
McGrath RE. Stephen.Page@uc.e=
du
OBJECTIVE: To determine efficacy of a modified
constraint-induced movement therapy (mCIMT) pro=
tocol
for patients with chronic stroke. DESIGN: Multiple-baseline, pre-post,
single-blinded randomized controlled trial. SETTING: Outpatient clinic.
PARTICIPANTS: Seventeen patients who experienced stroke more than 1 year be=
fore
study entry and who had upper-limb hemiparesis =
and
learned nonuse. INTERVENTION: Seven patients participated in structured the=
rapy
sessions emphasizing more affected arm use in valued activities, 3 times a =
week
for 10 weeks. Their less affected arms were also restrained 5d/wk for 5 hou=
rs (mCIMT). Four patients received regular therapy with s=
imilar
contact time to mCIMT. Six patients received no
therapy (control). MAIN OUTCOME MEASURES: The Fugl-Meyer
Assessment of Motor Recovery (FMA), Action Research Arm (ARA) Test, and Mot=
or
Activity Log (MAL). RESULTS: The mCIMT patients
exhibited greater motor changes on the FMA and ARA (18.4, 11.4) than regular
therapy (6.0, 7.1) or control (-2.9, -4.5). Statistical analyses showed
significant differences in motor improvement on the FMA (F(2,12)=3D11.2,
P=3D.002) and the ARA (F(2,12)=3D14.0, P=3D.001). Post hoc analyses showed =
that, when
pretreatment motor differences are controlled, mCIMT=
span>
resulted in substantially higher posttreatment =
FMA
and ARA scores. Amount and quality of arm use, measured=
by
the MAL, improved only in mCIMT patients.
CONCLUSIONS: mCIMT may be an efficaci=
ous
method of improving function and use of the more affected arms of chronic
stroke patients. Findings further affirm that repeated, task-specific pract=
ice
is critical to reacquisition of function, whereas practice schedule intensi=
ty
is less critical.
Can J Physiol Pharmacol. 2004 Apr;82(4):=
231-7.
Immediate constraint-induced movement therapy cau=
ses
local hyperthermia that exacerbates cerebral cortical injury in rats.
DeBow=
SB,
McKenna JE, Kolb B, Colbourne F.
&=
nbsp; Constraint-induced
movement therapy (CIMT), which involves restraint of the nonimpaired
arm coupled with physiotherapy for the impaired arm, lessens impairment and
disability in stroke patients. Surprisingly, immediate ipsilateral
forelimb immobilization exacerbates brain injury in rats. We tested whether
immediate ipsilateral restraint for 7 days aggr=
avates
injury after a devascularization lesion in rats.
Furthermore, we hypothesized that ipsilateral
restraint aggravates injury by causing hyperthermia. In experiment 1, each =
rat
received two lesions, one in the motor cortex and one in the visual cortex.=
Ipsilateral restraint increased only the motor cortex
lesion. In additional rats, no differences in core temperature occurred aft=
er ipsilateral or contralateral
restraint. Thus, ipsilateral restraint does not
aggravate injury by a systemic side effect. In experiment 2, we hypothesized
that ipsilateral restraint =
causes
hyperthermia in the region surrounding the initial cortical lesion. Brain
temperature, measured via telemetry, was significantly higher (approximatel=
y 1
degrees C for 24 h) with ipsilateral restraint.=
A
third experiment similarly found that ipsilateral
restraint aggravates injury and causes local cortical hyperthermia and that=
contralateral restraint with externally induced mild
hyperthermia aggravates injury. In conclusion, immediate ipsilateral
restraint aggravates injury apparently by localized events that include
hyperthermia. Caution must be exercised in applying early CIMT to humans, as
hyperthermia is detrimental. =
(We
already know that CIMT can’t work until resolution of diaschesis,
etc., which takes at least 6 months in humans...).
Stroke. 2004 Sep 16 [Epub ahead of print]&=
nbsp;
Constraint-Induced Movement T=
herapy.
Grotta JC, Noser
EA, Ro T, Boake C, Levin H, Aronowski
J, Schallert T.
&n=
bsp; Constraint-induced
movement therapy improves outcome after chronic stroke, conforms experiment=
al
observations of neuronal plasticity, and proves the efficacy of intensive
occupational therapy. More acutely instituted constraint-induced movement
therapy has both practical and theoretic risks and benefits that deserve
further careful evaluation.
**********PLASTICIT=
Y end*
***REHABILITATIO=
N
Arq Neuropsiquiatr.
2002 Mar;60(1):21-7
Cognitive rehabilitation of n=
aming
deficits following viral meningo-encephalitis.<=
/b>
Miotto EC
Department of Neuropsychology, T=
he
&n=
bsp; OBJECTIVE:
This case study describes the neuropsychological assessment and cognitive
rehabilitation of a patient who developed word retrieval deficits for objec=
ts
and people's names, following an episode of viral meni=
ngo-encephalitits.
It shows the implementation and outcome of two techniques adapted to the
patient's individual characteristics and context providing a more ecologica=
lly
valid approach. METHODS: In the first technique, "verbal semantic
association", the patient was required to describe what she knew about=
an
object as a strategy to help her retrieve its name. In the second one,
"face-name association" she was taught to apply a visual-imagery
technique in order to retrieve relevant people's names. RESULTS: Following =
the
implementation of these procedures there was a decrease in the number of
episodes of failure to retrieve objects and people's names in her everyday =
life
context. CONCLUSION: The improvement found in the patient's ability to
retrieve words is discussed in terms of the utility of cognitive rehabilita=
tion
programmes and cognitive models of language
processing
Journal of Neurology Neurosurgery and Psychiatry 200=
2;73:173-181
Functional reorganisation of
memory after traumatic brain injury: a study with H2150 positron emission
tomography
B Levine, R Cabeza, AR M=
cIntosh,
SE Black, CL Grady, DT Stuss;
levine@psych.utoronto.ca
&n=
bsp; Objective:
To study the effects of moderate to severe traumatic brain injury (TBI) on =
the
functional neuroanatomy supporting memory retri=
eval.
&n=
bsp; Methods:
Subjects were six patients who had sustained a moderate to severe TBI about
four years before scanning and had since made a good recovery. Eleven healt=
hy
young adults matched to the patients for age and education served as contro=
ls.
An established H2150 positron emission tomography paradigm was used to elic=
it
brain activations in response to memory retrieval. TBI patients' patterns of
brain activation were compared statistically with those of control subjects.
Both group and individual case data were analysed.
&n=
bsp; Results:
Both TBI patients and controls engaged frontal, temporal, and parietal regi=
ons
known to be involved in memory retrieval, yet the TBI patients showed relat=
ive
increases in frontal, anterior cingulate, and
occipital activity. The hemispheric asymmetry characteristic of controls was
attenuated in patients with TBI. Reduced activation was noted in the right =
dorsomedial thalamus. Although local aspects of this =
pattern
were affected by the presence of focal lesions and performance differences,=
the
overall pattern was reliable across patients and comparable to functional <=
span
class=3DSpellE>neuroimaging results reported for normal aging, Alzhe=
imer's
disease, and other patients with TBI.
&n=
bsp; Conclusions:
The TBI patients performed memory tasks using altered functional neuroanatomical networks. These changes are probably =
the
result of diffuse axonal injury and may reflect either cortical disinhibition attributable to disconnection or compen=
sation
for inefficient mnemonic processes.
Curr=
Opin Pediat=
r.
2004 Apr;16(2):217-26.
Update on attention-deficit/hyperactivity disorde=
r.
Daley KC.
Department of Medicine, Children=
's
Hospital Boston,
&n=
bsp; PURPOSE
OF REVIEW: Attention-deficit/hyperactivity disorder (ADHD) is present in 3%=
to
10% of children in the
Neuroimage<=
/span>. 2004 Jan;21(1):436-43.
Learned regulation of spatial=
ly
localized brain activation using real-time fMRI=
.
deCharms
RC, Christoff K, Glover GH, Pauly
JM, Whitfield S, Gabrieli JD.
Department of Psychology,
&n=
bsp; It
is not currently known whether subjects can learn to voluntarily control
activation in localized regions of their own brain using neuroimaging.
Here, we show that subjects were able to learn enhanced voluntary control o=
ver
task-specific activation in a chosen target region, the somatomotor
cortex. During an imagined manual action task, subjects were provided with
continuous direction regarding their cognitive processes. Subjects received
feedback information about their current level of activation in a target re=
gion
of interest (ROI) derived using real-time functional magnetic resonance ima=
ging
(rtfMRI), and they received automatically-adjus=
ted
instructions for the level of activation to achieve. Information was provid=
ed
both as continously upated=
graphs and using a simple virtual reality interface that provided an image
analog of the level of activation. Through training, subjects achieved an
enhancement in their control over brain activation that was anatomically
specific to the target ROI, the somatomotor cor=
tex.
The enhancement took place when rtfMRI-based tr=
aining
was provided, but not in a control group that received similar training wit=
hout
rtfMRI information, showing that the effect was=
not
due to conventional, practice-based neural plasticity alone. Following
training, using cognitive processes alone subjects could volitionally induc=
e fMRI activation in the somatomot=
or
cortex that was comparable in magnitude to the activation observed during
actual movement. The trained subjects increased fMR=
I
activation without muscle tensing, and were able to continue to control bra=
in
activation even when real-time fMRI information=
was
no longer provided. These results show that rtfMRI
information can be used to direct cognitive processes, and that
subjects are able to learn volitionally regulate activation in an
anatomically-targeted brain region, surpassing the task-driven activation
present before training. (impact factor >=
.6)
Appl=
Psychophysiol Biofeedback. 2002
Dec;27(4):231-49.
The effects of stimulant ther=
apy, EEG
biofeedback, and parenting style on the primary symptoms of
attention-deficit/hyperactivity disorder.
Monas=
tra VJ,
Monastra DM, George S.
FPI Attention Disorders Clinic, =
&n=
bsp; One
hundred children, ages 6-19, who were diagnosed with
attention-deficit/hyperactivity disorder (ADHD), either inattentive or comb=
ined
types, participated in a study examining the effects of Ritalin, EEG
biofeedback, and parenting style on the primary symptoms of ADHD. All of the
patients participated in a 1-year, multimodal, outpatient program that incl=
uded
Ritalin, parent counseling, and academic support at school (either a 504 Pl=
an
or an IEP). Fifty-one of the participants also received EEG biofeedback
therapy. Posttreatment assessments were conduct=
ed
both with and without stimulant therapy. Significant improvement was noted =
on
the Test of Variables of Attention (TOVA; L. M. Greenberg, 1996) and the
Attention Deficit Disorders Evaluation Scale (ADDES; S. B. McCarney,
1995) when participants were tested while using Ritalin. However, only t=
hose
who had received EEG biofeedback sustained these gains when tested without
Ritalin. The results of a Quantitative Electroencephalographic Scanning
Process (QEEG-Scan; V. J. Monastra et al., 1999)
revealed significant reduction in cortical slowing only in patients who =
had
received EEG biofeedback. Behavioral measures indicated that parenting style
exerted a significant moderating effect on the expression of behavioral
symptoms at home but not at school.
J Clin Exp Neuropsychol. 2003
Sep;25(6):805-14. Related
Articles, Links &nb=
sp;
Implicit
learning in memory rehabilitation: a meta-analysis on errorless learning and
vanishing cues methods.
Kessels RP, de Haan
EH.;R.Kessels@fss.uu.nl
The
objective of this study was to present a quantitative review on the treatme=
nt
effects of memory rehabilitation techniques based on intact implicit learni=
ng
capacity in amnesic patients, that is, errorless learning and the method of
vanishing cues. English-language journal articles focusing on these
rehabilitation techniques were examined using MedLine<=
/span>
(1966-2002) or PsychInfo (1887-2002), as well as
additional papers listed in the references of these articles. Studies had to
meet the following inclusion criteria: (1) original data were reported, (2)
memory rehabilitation was studied in memory-impaired patients, (3) a control
intervention was included, (4) exact scores were listed for both interventi=
on
conditions, or the exact statistics were presented. Studies were classified=
on
the basis of the to-be-learned material and the method of intervention
(errorless learning, vanishing cues, control intervention), patient
characteristics were determined, and the tasks that were used were taken in=
to
account. Effect sizes and variances were computed for each individual study
compared to control treatment using within-group statistics. A "large&=
quot;
and statistically significant ES was found for errorless learning treatment,
but no significant ES was demonstrated for the vanishing cues method. The
results of the present study show that the errorless learning technique is
effective in amnesic patients. The effects on the vanishing cues method are
only small (and nonsignificant).
Age Ageing. 2003 Sep;32(5):=
529-33.
Mnemonic
strategies in older people: a comparison of errorless and errorful
learning.
Kessels RP, de Haan EH.; r.kessels@fss.uu.nl
OBJECTIVE: To compare the efficacy of errorless and errorful learning on memory performance in older people and young adults. METHODS: Face-name association learning was examined in 18 older people and 16 young controls. Subjects were either prompted to guess the correct name during the presentation of photographs of unknown faces (errorful= learning) or were instructed to study the face without guessing (errorless learning). The correct name was given after the presentation of each face in both task conditions. Uncued testing followed immediately after the two study phases and after a 10-minute delay. RESULTS: Older subjects had an overall lower memory performance and flatter learning curves compared to the young adults, regardless of task conditions. Also, errorless learning resulted in a higher accuracy than = errorful learning, to an equal amount in both groups. CONCLUSIONS: Older people have difficulty in the encoding stages of face-name association learning, whereas retrieval is relatively unaffected. In addition, the prevention of errors occurring during learning results in a better memory performance, and is perhaps an effective strategy for coping with age-related memory decrement<= o:p>
Neuropsycho=
logia. 2003;41(9):1230-40.
An investigation of errorless learning in memory-=
impaired
patients: improving the technique and clarifying theory.
Tailby R, Haslam
C.
In rehabilitating individuals who demonstrate severe
memory impairment, errorless learning techniques have proven particularly
effective. Prevention of errors during acquisition of information leads to
better memory than does learning under errorful
conditions. This paper presents results of a study investigating errorless
learning in three patient groups: those demonstrating mild, moderate, and
severe memory impairments. The first goal of the study was to trial a new
version of errorless learning, one encouraging more active participation in
learning by patients via the use of elaboration and self-generation. This
technique led to significantly better memory performance than seen under
standard errorless conditions. This finding highlights the value of encoura=
ging
active and meaningful involvement by patients in errorless learning, to bui=
ld
upon the benefits flowing from error prevention. A second goal of the study=
was
to clarify the mechanisms underlying errorless learning. Memory performance
under errorless and errorful conditions was com=
pared
within and across each group of patients, to facilitate theoretical insight
into the memory processes underlying performance. The pattern of results
observed was equivocal. The data most strongly supported the hypothesis =
that
the benefits seen under errorless learning reflect the operation of residual
explicit memory processes, however a concurrent role for implicit memory
processes was not ruled out.
J Neuropsychiatry Clin
Neurosci. 2003 Spring;15(2):130-44.
A critical review of memory stimulation programs =
in
Alzheimer's disease.
Grandmaison E, Simard M.
Geriatric Neuropsychology Laboratory, School of
Psychology, Universit de M=
oncton,
Moncton, New Brunswick, Canada.
eric.grandmaison@gnb.ca
&n=
bsp; The
authors describe the memory stimulation programs used in the treatment of
Alzheimer's disease (AD) and review their efficacy. Visual imagery, errorle=
ss
learning, dyadic approaches, spaced retrieval techniques, encoding specific=
ity
with cognitive support at retrieval, and external memory aids were the memo=
ry
stimulation programs used alone or in combination in AD. Preliminary eviden=
ce
suggests that the errorless learning, spaced retrieval, and vanishing cues
techniques and the dyadic approach, used alone or in combination, are
efficacious in stimulating memory in patients with AD.
Psychol Med. 2003 Apr
Does 'errorless learning' compensate for neurocog=
nitive
impairments in the work rehabilitation of persons with schizophrenia?
Kern RS, Green MF, Mintz
J, Liberman RP.
&n=
bsp; BACKGROUND:
Because neurocognitive impairments of schizophrenia appear to be 'rate
limiting' in the acquisition of skills for community functioning, it is
important to develop efficacious rehabilitative interventions that can
compensate for these impairments. Procedures based on errorless learning may
facilitate work rehabilitation because they effectively automate training of
work and other skills, thereby reducing the cognitive burden on persons with
schizophrenia. METHOD: The present study examined the ability of a training
method based on errorless learning to compensate for neurocognitive deficit=
s in
teaching two entry-level job tasks (index card filing and toilet-tank assem=
bly)
to a sample of 54 unemployed, clinically stable schizophrenic and
schizoaffective disorder out-patients. Participants were randomly assigned =
to
one of two training groups, errorless learning v. conventional trial-and-er=
ror
type instruction. Prior to randomization, all subjects were administered a
neurocognitive battery. Job task performance was assessed by percentage
accuracy scores immediately after training. RESULTS: For three of the six
inter-relationships among neurocognitive functioning and training condition,
the pattern was the same: the errorless learning group scored high in job t=
ask
performance regardless of neurocognitive impairment, whereas the convention=
al
instruction group showed a close correspondence between job task performanc=
e and
degree of neurocognitive impairment. CONCLUSIONS: These findings support
errorless learning as a technique that can compensate for neurocognitive
deficits as they relate to the acquisition of new skills and abilities in t=
he
work rehabilitation of persons with schizophrenia.
Neurofee=
dback in Psychological Practice.
Masterpasqu=
a, Frank; Healey, Kathryn N.
Professional Psychology - Resear=
ch &
Practice. 34(6):652-656, December 2003.
&n=
bsp; Advances
in technology occasionally allow for innovations in the practice of psychol=
ogy.
Neurofeedback is one such modality; in it,
individuals learn to change patterns of brain waves through operant
conditioning. Research shows that a number of neurological and psychological
disorders can be characterized by distinctive EEG patterns and that neurofeedback may help clients to change those patter=
ns.
The evidence regarding neurofeedback's efficacy=
for
attention-deficit/hyperactivity disorder (ADHD), depression, and other
disorders is reviewed. Using control group designs, four different resea=
rch
teams have found neurofeedback to be effective =
for
ADHD participants; research on outcomes for other disorders is at a much mo=
re
preliminary stage. Practicing psychologists are encouraged to explore the
potential of this alternative and distinctly psychological modality.
J Autism Dev Disord.
2003 Oct;33(5):519-26.
Sequential evaluation of rein=
forced
compliance and graduated request delivery for the treatment of noncomplianc=
e in
children with developmental disabilities.
Ducharme JM, Harris K, M=
illigan
K, Pontes E.
Department of Human Development =
and
Applied Psychology,
&n=
bsp; Errorless
compliance training is a recently developed approach that has been demonstr=
ated
to be effective in treating severe oppositional behavior in children. In
conjunction with several ancillary techniques, the approach comprises two
fundamental components: reinforcement for child compliance and delivery of
requests in a four-level hierarchy, from requests that yield high levels of
compliance to those that yield low levels. To determine the relative
contribution of each component, four children with developmental disabiliti=
es
and severe oppositional behavior were observationally assessed in baseline =
and
then treated using reinforcement following each instance of compliance to
parental requests. Following this first treatment phase, we used the gradua=
ted
request hierarchy in conjunction with reinforced compliance. Results indica=
ted
that use of reinforcement for compliance in isolation was ineffective in
bringing about clinically significant improvements in child compliance. The
addition of the graduated request hierarchy appeared to be associated with
substantial changes in child compliance that maintained in follow-up
assessments.
Journal of Rehabilitation Medicine Volume 35, Number 6 / December 2003, 276 - 283=
Explaining labor force status following spinal co=
rd
injury: the contribution of psychological variables
Gregory C. Murphy, Amanda E. Young, Douglas J. Brown,
Neville J. King
&n=
bsp; Objective:
To investigate the relative influence of demographic, injury and psychologi=
cal
characteristics on the labor force status of people living with spinal cord
injury. Design: Cross-sectional survey. Subjects: 459 persons who had
experienced a traumatic spinal cord injury. All participants were patients =
of 1
of 2 specialist spinal cord injury services located in south-eastern
Experimental Neurology, In press
Sodium channel blockade with phenytoin
protects spinal cord axons, enhances axonal conduction, and improves functi=
onal
motor recovery after contusion SCI
Bryan C. Hains, Carl Y. =
Saab,
Albert C. Lo and Stephen G. Waxman,
&n=
bsp; Accumulation
of intracellular sodium through voltage-gated sodium channels (VGSCs) is an important event in the cascade leading to
anatomic degeneration of spinal cord axons and poor functional outcome
following traumatic spinal cord injury (SCI). In this study, we hypothesized
that phenytoin, a sodium channel blocker, would
result in protection of axons with concomitant improvement of functional
recovery after SCI. Adult male Sprague–Dawley
rats underwent T9 contusion SCI after being fed normal chow or chow contain=
ing phenytoin; serum levels of pheny=
toin
were within therapeutic range at the time of injury. At various timepoints after injury, quantitative assessment of l=
esion
volumes, axonal degeneration, axonal conduction, and functional locomotor recovery were performed. When compared to
controls, phenytoin-treated animals demonstrated
reductions in the degree of destruction of gray and white matter surrounding
the lesion epicenter, sparing of axons within the dorsal corticospinal
tract (dCST) and dorsal column (DC) system rostral to the lesion site, and within the dorsolateral funiculus (D=
LF)
caudal to the lesion site, and enhanced axonal conduction across the lesion
site. Improved performance in measures of skilled loco=
motor
function was observed in phenytoin-treated anim=
als.
Based on these results, we conclude that phenytoin<=
/span>
provides neuroprotection and improves functional
outcome after experimental SCI, and that it merits further examination as a
potential treatment strategy in human SCI.
Archives of Physical Medicine and Rehabilitation, 85=
, 7 , July 2004, Pages 1198-1204
Hyperbaric oxygen therapy for traumatic brain inj=
ury: a
systematic review of the evidence
Marian McDonagh PharmD, Mark Helfand MD, =
MS,
Susan Carson MPH and Barry S. Russman MD
&n=
bsp; McDonagh M, Helfand M, Ca=
rson S, Russman BS. Hyperbaric oxygen therapy for traumatic b=
rain
injury: a systematic review of the evidence. Arch Phys Med Rehabil
2004;85:1198–204. Objectiv=
e To identify the benefits and=
harms
of hyperbaric oxygen therapy (HBOT) to treat traumatic brain injury (TBI).<=
/span> Data sources MEDLINE, EMBASE, the Cochrane
Library, HealthSTAR, CINAHL, MANTIS, profession=
al
society databases, and reference lists. Databases were searched from incept=
ion
through December 2003. =
Study
selection We
included English-language studies of patients with TBI given HBOT and
evaluating functional health outcomes. Data extraction Data were abstracted by 1 re=
viewer
and checked by a second. Study quality was rated as good, fair, or poor.
Conclusions &n=
bsp;
The evidence for HBOT for TBI is insufficient to prove effectiven=
ess
or ineffectiveness, and more high-quality studies are needed. The evidence
indicates that there is a small chance of a mortality benefit, which may de=
pend
on subgroup selection. The effect on functional status and the incidence and
clinical significance of adverse effects are unclear.
Rehabilitation following acquired brain injury: c=
oncise
guidance
Clinical Medicine, Journal of the Royal College of
Physicians 1 January 2004, vol. 4, no. 1, pp. 61-65(5)
Turner-Stokes L.; Wade D.
&n=
bsp; The
national clinical guidelines for Rehabilitation following acquired brain in=
jury
were developed by a multidisciplinary working party convened by the British
Society of Rehabilitation Medicine, and are published in collaboration with=
the
Royal College of Physicians (2003). They have been produced to complement t=
he
National Institute of Clinical Excellence head injury guidelines, and to
address the medium- to longer-term needs of patients with acquired brain in=
jury
and of their families/carers. This article s=
erves
as an introduction to make physicians aware of the guidelines, and to highl=
ight
in particular the advice to doctors in the acute services regarding early
discharge and referral to rehabilitation.
Investigating the neurobiological basis of cognit=
ive
rehabilitation therapy with fMRI
L. K. Laats=
ch ; K. R. Thulborn ; C. M. =
Krisky ; D. M. Shobat ; J=
. A.
Sweeney
Source: Brain Injury Volume: 18
Number: 10 Page: 957 -- 974
&n=
bsp; Abstract:
The neurobiological changes occurring during cognitive rehabilitation thera=
py
(CRT) have yet to be systematically studied. In the present study, function=
al
magnetic resonance imaging (fMRI) was used to
demonstrate brain plasticity in response to CRT (n =3D 5) following mild
traumatic brain injury. Neuropsychological tests and two fMRI
activation tasks, a visually guided saccades and a reading comprehension ta=
sk,
were employed pre- and post-CRT. CRT was used to systematically address the
identified deficits in visual scanning and language processing. As
hypothesized, changes in the pattern and extent of activation within expect=
ed neuroanatomical areas occurred
post-CRT. Changes in fMRI activation are discus=
sed
for each subject and related to changes on neuropsychological measures. This
study demonstrates how fMRI can illus=
trate
the neurobiological mechanisms of recovery in individual subjects. The
variability in subject responses to CRT supports the notion of tailoring
rehabilitation strategies to each subject in order to optimize recovery
following brain injury.
Cognitive training in home environment
I.-L. Boman= ; M. Lindstedt ; H. Hemmingsson ; A. Bartfai<= o:p>
Source: Brain Injury Volume: 18
Number: 10 Page: 985 -- 995
&n=
bsp; Abstract:
Primary objective: To examine the efficacy of cognitive rehabilitation in t=
he
patient's home or vocational environment. Research design: Pre-post-follow-=
up
design. Methods and procedures: Ten outpatients with acquired attention and
memory problems received cognitive training three times weekly, for 3 weeks.
They received individual attention training with Attention Process Training,
training for generalization for everyday activities and education in
compensatory strategies for self-selected cognitive problems. Treatment eff=
ects
were evaluated with neuropsychological and occupational therapy instruments
before and after the training and after 3 months on impairment, activity and
participation levels. Main outcomes and results: The results indicated a
positive effect on some measures on impairment level, but no differences on
activity or participation levels at follow-up.
Conclusions: The study indicates that home-based
cognitive training improves some attentional and
memory functions and facilitates learning of strategies. Future controlled
studies are needed to confirm the results and analyse<=
/span>
the efficacy of different aspects of home-based training.
Neurology. 2004 Aug 10
Corticocortical
coupling in chronic stroke: its relevance to recovery.
Strens LH, Asselman
P, Pogosyan A, Loukas C,
Thompson AJ, Brown P.
BACKGROUND: The mechanisms behind motor recovery from stroke are not
clearly understood. Functional imaging studies have demonstrated task-relat=
ed
brain activation in several motor areas, but few studies have attempted to
correlate this with stroke outcome. Moreover, these studies have focused on=
how
motor areas may individually contribute to compensation. Here, the authors
investigate whether different cortical areas interact to form dynamic
assemblies that may then compensate for disability. METHODS: The authors
investigated corticocortical coherence in 16 he=
althy
subjects and 25 patients with chronic stroke involving one cerebral hemisph=
ere
and having varying degrees of motor recovery. Scalp EEG was recorded at rest
and while right-handed subjects performed a unimanual<=
/span>
grip task. The degree of functional recovery after stroke was assessed usin=
g a
range of outcome measures. RESULTS: Compared with healthy subjects,
hand-related asymmetries in task-related EEG-EEG coherence were increased
between mesial and lateral frontal regions of t=
he
affected hemisphere, over mesial frontal region=
s, and
over lateral frontal areas of the unaffected hemisphere when patients with
stroke gripped with their affected hand. Mesial
hand-related asymmetries in task-related power and coherence were negatively
correlated with recovery. CONCLUSION: Increases in task-related coup=
ling
between cortical areas may dynamically compensate for brain damage after st=
roke.
Some of this increased coupling, particularly that over mesial
frontal areas, decreases as patients make a functional recovery.
Brain, Vol. 127, No. 8, 1853-1867, August 2004
The scope of preserved procedural memory in amnes=
ia
Sara Cavaco, Steven W. A=
nderson,
John S. Allen, Alexandre Castro-Caldas
and Hanna Damasio
sara.cavaco@mail.telepac.pt
&n=
bsp; The
finding that patients with amnesia retain the ability to learn certain
procedural skills has provided compelling evidence of multiple memory syste=
ms
in the human brain, but the scope, defining features and ecological
significance of the preserved mnemonic abilities have not yet been explored.
Here, we tested the hypothesis that subjects with amnesia would be able to
learn and retain a broad range of procedural skills, by examining their
acquisition and retention performance on five novel experimental tasks. The
tasks are based on real-world activities and encompass a broad range of
perceptual–motor demands: (i) the weaving=
task
involves weaving pieces of fabric from woollen
strings, using a manual weaver's loom; (ii) the geometric figures task cons=
ists
of tracing geometric figures with a stylus as they move horizontally across=
a
touch screen monitor; (iii) the control stick task involves tracking a sequ=
ence
of visual target locations using a joystick control; (iv) the pouring task
consists of pouring 200 ml of water from a watering can into a series of
graduated cylinders, from a point 20 cm above the cylinders; and (v) the
spatial sequence task involves learning an ordered sequence of pushing five
spatially distributed buttons without visual guidance. Ten chronic and stab=
le
amnesic subjects (nine with bilateral medial temporal lobe damage due to he=
rpes
simplex encephalitis or anoxia, and one with thalamic stroke) and 25 matchi=
ng
normal comparison subjects were tested on three occasions: initial learning=
at
time 1; retention at time 2 (24 h later); and retention at time 3 (2 months
later). Despite impaired declarative memory for the tasks, the amnesic subj=
ects
demonstrated acquisition and retention of the five skills; their learning
slopes over repeated trials were comparable with those of comparison subjec=
ts. These
findings indicate that preserved learning of complex perceptual–motor
skills in patients with amnesia is a robust phenomenon, and that it can be
demonstrated across a variety of conditions and perceptual–motor dema=
nds.
The comparability of the tasks employed in this study with real-world
activities highlights the potential application of this memory dissociation=
in
the rehabilitation of patients with amnesia.
Brain, Vol. 127, No. 8, 1899-1908, August 2004
Globus pallidus internus stimula=
tion in
primary generalized dystonia: a H215O PET study=
Olivier Detante, Laurent=
Vercueil, Stéphane=
Thobois, Emmanuel Broussolle,
Nicolas Costes, Franck Lav=
enne,
Stéphan Chabardes=
span>,
Didier Lebars, Marie Vidai=
lhet,
Alim-Louis Benabid =
and
Pierre Pollak
Lvercueil@chu-grenoble.fr
&n=
bsp; Globus pallidus internus (GPi) deep brain
stimulation (DBS) increasingly shows promising efficacy in the treatment of
severe primary generalized dystonia. Functional
imaging studies have shown previously that dystonia
could be related to abnormal cortical activation during voluntary movement.=
In
the present study, the effects of GPi DBS on re=
gional
cerebral blood flow (rCBF) during a motor task =
were
studied in patients with primary generalized dystonia<=
/span>.
rCBF was measured us=
ing
H215O and PET in eight control subjects and six patients with dystonia treated with bilateral =
GPi
DBS. Subjects were scanned at rest and while performing joystick movements.=
Dystonic patients were tested in two conditions:
‘OFF’ (stimulator bilaterally switched off) and ‘ON’
(unilateral stimulation). In the ‘OFF’ condition, compared with
rest, motor activation of the most dystonic han=
d was
associated with overactivity in the contralateral dorsolateral
prefrontal cortex, gyrus f=
rontalis
medialis, superior frontal gyrus
(area 10), frontoorbital cortex and thalamus. I=
n the
‘ON’ condition, GPi DBS contralaterally to the most dyst=
onic
hand induced a decrease of the overactivation i=
n the
same areas, as well as the putamen. Accordin=
g to
the present study, generalized dystonia is asso=
ciated
with prefrontal overactivation which can be rev=
ersed
by effective GPi DBS.