Longitudinal plasticity across the neural axis in acute stroke.
BACKGROUND
With the advent of novel brain stimulation techniques aimed at improving functional outcome, understanding poststroke plasticity becomes critical for the appropriate selection of patients and optimal timing to introduce neuromodulatory interventions.


OBJECTIVE
To better define the temporal evolution of central and peripheral neuroplastic changes in the first 3 months after stroke and their clinical implications.


METHODS
Transcranial magnetic stimulation, peripheral nerve excitability, and clinical assessments were undertaken longitudinally in 31 acute stroke patients, comprising a total of 384 clinical studies.


RESULTS
During the hyperacute phase (<7 days), short-interval intracortical inhibition (SICI) was significantly reduced in lesioned (4.3% ± 1.3%) and contralesional hemispheres (3.6% ± 1.9%) compared with controls (11.4% ± 1.3%, P = .001). There were also significant alterations in accommodative properties of motor axons in the affected limb. At follow-up, SICI remained suppressed in both hemispheres in the context of significant clinical improvement.


CONCLUSIONS
Simultaneous assessment of central and peripheral motor pathways has identified bilateral plastic changes that develop throughout the neural axis in acute stroke patients. It is proposed that these changes represent an adaptive response and that the persistent bihemispheric reduction in SICI may act to promote stroke recovery through cortical reorganization.
Neuroscience Research Australia, Randwick, New South Wales, Australia. w.huynh@neura.edu.au
William
W
Huynh
Steve
S
Vucic
Arun V
AV
Krishnan
Cindy S-Y
CS
Lin
Michael
M
Hornberger
Matthew C
MC
Kiernan
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000503:physiopathology*; D004525:Efferent Pathways / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D010525:Peripheral Nerves / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome