Segmental myoclonus in a young man who had had localized encephalitis in childhood.

A man who had had an episode of localized encephalitis, diagnosed as viral cerebellitis in childhood came to observation at the age of 23 for attacks of segmental myoclonus of the cervical axial musculature. BAEP changes at brainstem level in this case point to involvement of the Guillain-Mollaret triangle in the pathogenesis of this syndrome.