Motor evoked potentials: prognostic value in motor recovery after stroke

Accurate motor and functional prognosis after stroke is important for the optimal planning of a personalised rehabilitation programme, and clinical, demographic and radiological data are commonly employed for this purpose. It is becoming increasingly apparent that motor evoked potentials (MEPs), obtained through transcranial magnetic stimulation, can furnish complementary prognostic information on motor outcome after stroke, particularly when initial hand palsy is present. To evaluate the prognostic value of early MEPs together with other clinical variables, 19 subjects with first- ever stroke in the middle cerebral artery territory and hand palsy at onset, were evaluated in the acute phase. These cases were retrospectively selected out of a sample of 33 subjects. Multivariate analysis was carried out using amplitude of MEPs, National Institutes of Health Stroke Scale score (NIH) and Motricity Index as independent variables, and Medical Research Council scale score (MRC) as the dependent outcome variable at 4 months after stroke. The best model, which combined NIH and MEP data, accounted for 75.44% of the variability of the MRC. Our results suggest that the NIH and MEPs may yield information useful for predicting hand motor outcome after stroke in the presence of initial hand palsy, a condition in which a prognosis made on the basis solely of clinical data is deemed more difficult.