Myoclonic epilepsy in an HIV positive patient: neurophysiological findings.

An HIV-positive patient is described who presented with action myoclonus. Unusually, focal sinusoidal EEG burst complexes with a frequency of 40 and 55 Hz could be recorded over the sensorimotor cortex. Activity having a similar frequency was evoked in this area by posterior tibial nerve stimulation in the affected leg, and jerk-locked averaging showed that myoclonic jerks were preceded by similar cortical sinusoidal waves.