Article

Myoclonus is a sudden brief (20-250 ms) contraction (positive myoclonus), or a
brief and sudden cessation of tonic muscle (negative myoclonus) inducing a simple
jerky movement of body part. Myoclonus could have different origins in almost
every part of the nervous system, from the cortex to the peripheral nerve,
sharing a large panel of etiologies. It is regarded as the paradigmatic movement
disorder causing jerks, although not the sole.
This paper aims to depict the
clinical and neurophysiological characteristics of myoclonus. It shows how
neurophysiological investigations including surface polymyography and methods
exploring cortical excitability, namely conventional EEG,
EEG - jerk-locked
back-averaging, somatosensory evoked potentials and C-reflex studies are required
to define the generator of myoclonus in the central nervous system and clearly
classify myoclonus as cortical, corticothalamic, subcortical - resulting from
lesions or dysfunctions of basal ganglia/reticular system - or spinal. This paper
also enlightens other movement disorders that may mimic myoclonus appearances,
including psychogenic jerks, simple motor tics, spasms and startle syndromes.
Finally, it raises few unresolved questions regarding the propriospinal myoclonus
or peripheral myoclonus entities, the role of the cerebellum in myoclonic
diseases and the relationship between cortical and epileptic myoclonus.
CI - Copyright (c) 2016. Published by Elsevier Masson SAS.

Langue : ANGLAIS