[Contribution of electrophysiology to the study of a paresis of central origin].
Motor evoked potentials (MEPs) to magnetic transcranial stimulation allow a functional study of the central motor pathways (from cortex to muscle). The method--noninvasive, painless and hazard-free--is readily accepted by the patients. Two main parameters are measured, namely the central motor conduction time (CMCT) and the size of the MEP. The CMCT provides information on the conduction velocity along the corticospinal pathway, it is particularly prolonged in myelin disorders. The size of MEPs correlates with the proportion of functioning motor neurons. A particular technique allows a precise quantification of conduction defects due to conduction blocks or neuronal lesions that are responsible for the paresis. Clinical applications of the method are numerous; mainly, to detect, measure and localize a dysfunction of central motor conduction of any origin. The method serves the diagnosis and on some occasions the prognosis; it allows the follow up of central motor paresis and the effect of treatments.
Magistris
Michel R
MR
Unité d'électroneuromyographie et des affections neuromusculaires Clinique de Neurologie Hôpitaux Universitaires de Genève 1211 Genève. michel.magistris@hcuge.ch
Truffert
André
A
Rösler
Kai M
KM
D004594:Electrophysiology; D019054:Evoked Potentials, Motor; D006801:Humans; D010243:Paralysis / Q000503:physiopathology*