Abnormal motor cortex excitability in congenital stroke.
The aim of the present study was to investigate corticospinal and intracortical excitability in patients with congenital stroke. In adults, stroke sequelae reduce corticospinal excitability, as indicated by an elevated threshold for motor evoked potentials (MEP), and increase intracortical excitability, as indicated by reduced intracortical inhibition. Ten patients with pre- or perinatally acquired, unilateral cortico-subcortical infarctions in the middle cerebral artery territory were studied with single pulse transcranial magnetic stimulation (TMS) to measure motor threshold (MT) and with paired pulse TMS to study short interval intracortical inhibition (SICI) and intracortical facilitation (ICF). Eight healthy, age-matched subjects served as controls. MT over the affected hemisphere of patients compared with the dominant hemisphere of controls was significantly elevated, reflecting reduced corticospinal excitability, and SICI was significantly reduced, reflecting increased intracortical excitability. No such differences were found for ICF. Findings in patients with congenital stroke were comparable with adulthood stroke. Thus, similar assumptions can be made: reduced corticospinal excitability is probably a consequence of neuronal damage. Reduced intracortical inhibition might represent deficient inhibitory cortical properties or might reflect a compensational mechanism, dispositioning for use-dependent plasticity.
Berweck
Steffen
S
Department of Pediatric Neurology and Developmental Medicine, Dr. von Hauners' Children's Hospital of the University of Munich, 80337 Munich, Germany. steffen.berweck@med.uni-muenchen.de
Walther
Michael
M
Brodbeck
Verena
V
Wagner
Nina
N
Koerte
Inga
I
Henschel
Volkmar
V
Juenger
Hendrik
H
Staudt
Martin
M
Mall
Volker
V
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D019054:Evoked Potentials, Motor; D005260:Female; D005858:Germany; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology*; D009433:Neural Inhibition; D009473:Neuronal Plasticity; D011712:Pyramidal Tracts / Q000473:pathology / Q000503:physiopathology; D012684:Sensory Thresholds; D020521:Stroke / Q000151:congenital / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D013997:Time Factors; D050781:Transcranial Magnetic Stimulation