Neurophysiological follow-up of motor cortical output in stroke patients

Background and purpose: Transcranial magnetic stimulation (TMS) has been em ployed in following up a population of 20 stroke patients in a post-acute, apparently stabilized stage. Neurophysiological and clinical data were reco rded in 5 different recording sessions, from the beginning of a neuro-rehab ilitation treatment (TO, at about 5 weeks from the ictal event.), followed up for about 4 months (T4), with the purpose to Study any modification of t he cortical motor output in the course of a neuro-rehabilitation treatment. Methods: Motor evoked potentials (MEPs) were simultaneously recorded from 1 0 muscles of both upper limbs (affected and not-affected): meanwhile, clini cal and functional scores were gathered. Spinal responsiveness was investig ated via H-reflex and F-wave recordings. Results: We describe a pattern of improving changes still taking place four months after the stroke, even ii the maximal amelioration burden was conce ntrated between T0 and T1 and T1 and T2 recording sessions (T0/admission to T2/42 days from T0 = about 80 days from stroke occurrence), in particular, the excitability threshold (ETh) was progressively decreasing in the affec ted hemisphere (AH; P < 0.001 between T0 and T4), while MEPs amplitude and latency tended toward normality, more in the resting state than during volu ntary contraction. Slopes of neurophysiological anti clinical data evolutio n were taken and trends of amelioration described. Conclusions: These findings suggest that rearrangements of motor cortical n eural circuitries are still operating after several months from an acute va scular monohemispheric insult, coupled with a clinical improvement in disab ility and neurological scores. The steepest part of the slopes were evident in the first 80 days, suggesting that this period is the one in which plas tic changes of cortical motor areas are mainly active. (C) 2000 Elsevier Sc ience Ireland Ltd. All rights reserved.