Myoclonic seizures

Involuntary shock-like contrations, irreguler in rhythm and amplitude, followed by relaxation, of a muscles. This condition may be a feature of some CENTRAL NERVOUS SYSTEM DISEASE (e.g., EPLIEPSY, MYOCLONIC). Nocturnal myoclonus may represent a normal physiologic event or occur as the principal feature of the NOCTURNAL MYOCLONUS SYNDROME.