TY - JOUR
T1 - Interhemispheric Asymmetries of Motor Cortex Excitability in the Postacute Stroke Stage
T2 - A Paired-Pulse Transcranial Magnetic Stimulation Study
AU - Cicinelli, Paola
AU - Pasqualetti, Patrizio
AU - Zaccagnini, Marina
AU - Traversa, Raimondo
AU - Olivefi, Massimiliano
AU - Rossini, Paolo Maria
PY - 2003/11
Y1 - 2003/11
N2 - Background and Purpose - Changes in the intracortical inhibition (ICI) and facilitation (ICF) of motor cortex paired-pulse transcranial magnetic stimulation were reported in the affected (AH) and unaffected (UH) hemispheres of stroke patients and reflect some of the mechanisms related to motor cortex plasticity and different degrees of functional recovery. The interhemispheric differences of the ICI/ICF slopes have been found to have a nearly identical time course in the 2 hemispheres of healthy subjects, and whether such symmetry is modified after monohemispheric stroke has not yet been examined. Our goal was to investigate the interhemispheric asymmetries of the time course of ICI/ICF between the AH and UH of stroke patients in the postacute phase of recovery. Methods - ICI/ICF recovery curves to subthreshold-conditioning suprathreshold-test magnetic stimuli were recorded from the paretic and nonparetic hand muscles of 10 well-recovered stroke patients and compared with those of a population of 10 control subjects. Results - In the healthy subjects, ICI/ICF showed a symmetrical time evolution between the 2 hemispheres. In stroke patients, the ICI/ICF slopes were significantly different between the UH and AH; the intracortical inhibition was reduced in the AH and normal in the UH. Conclusions - The defective AH ICI associated with the effective UH ICI could represent a marker of poststroke cortical plasticity implicated as a mechanism relevant to functional recovery. Analysis of the interhemispheric asymmetries of the ICI/ICF recovery curves might provide a valuable neurophysiological parameter in the prognosis and follow-up of patients with monohemispheric stroke.
AB - Background and Purpose - Changes in the intracortical inhibition (ICI) and facilitation (ICF) of motor cortex paired-pulse transcranial magnetic stimulation were reported in the affected (AH) and unaffected (UH) hemispheres of stroke patients and reflect some of the mechanisms related to motor cortex plasticity and different degrees of functional recovery. The interhemispheric differences of the ICI/ICF slopes have been found to have a nearly identical time course in the 2 hemispheres of healthy subjects, and whether such symmetry is modified after monohemispheric stroke has not yet been examined. Our goal was to investigate the interhemispheric asymmetries of the time course of ICI/ICF between the AH and UH of stroke patients in the postacute phase of recovery. Methods - ICI/ICF recovery curves to subthreshold-conditioning suprathreshold-test magnetic stimuli were recorded from the paretic and nonparetic hand muscles of 10 well-recovered stroke patients and compared with those of a population of 10 control subjects. Results - In the healthy subjects, ICI/ICF showed a symmetrical time evolution between the 2 hemispheres. In stroke patients, the ICI/ICF slopes were significantly different between the UH and AH; the intracortical inhibition was reduced in the AH and normal in the UH. Conclusions - The defective AH ICI associated with the effective UH ICI could represent a marker of poststroke cortical plasticity implicated as a mechanism relevant to functional recovery. Analysis of the interhemispheric asymmetries of the ICI/ICF recovery curves might provide a valuable neurophysiological parameter in the prognosis and follow-up of patients with monohemispheric stroke.
KW - Evoked potentials, motor
KW - Motor cortex
KW - Recovery of function
KW - Rehabilitation
KW - Stroke
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UR - http://www.scopus.com/inward/citedby.url?scp=0242694066&partnerID=8YFLogxK
U2 - 10.1161/01.STR.0000092122.96722.72
DO - 10.1161/01.STR.0000092122.96722.72
M3 - Article
C2 - 14551397
AN - SCOPUS:0242694066
VL - 34
SP - 2653
EP - 2658
JO - Stroke
JF - Stroke
SN - 0039-2499
IS - 11
ER -