Late responses after transcranial magnetic stimulation in stroke.
In addition to early responses after transcranial magnetic stimulation, usually designated as Motor Evoked Potentials (MEP), several late responses have been reported in intervals up to 500 ms following stimulus. Our attention in this work was focused on the response in interval 150-300 ms after stimulus output, which is also designated as S > 150 response. We monitored longitudinally late S > 150 response in group of 19 stroke patient with verified hemispherical ischemic lesion. Our results have shown that the presence of late S > 150 response on the first day after stroke predicts an excellent improvement of clinical deficit and that late S > 150 response is more sensitive to hemispheric lesion than early MEPs. From this point of view, recording of late responses can supplement early MEP recording. Our study demonstrated that supratentorial structures are involved in the origin of the S > 150 response. According to the observation that in some patients a normal early response was present and an S > 150 response was absent on the hemiparetic side, and both responses were present on the unaffected side, we hypothesize that cortical structures play an important role in S > 150 response.
Department of Neurology, Derer's Hospital, Bratislava, Slovak Republic.
J
J
Benetin
M
M
Kuchar
D000368:Aged; D000369:Aged, 80 and over; D002561:Cerebrovascular Disorders / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006429:Hemiplegia / Q000503:physiopathology; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D013997:Time Factors