UC Irvine

Myoclonus has been defined as a sudden, involuntary, brief, shock-like muscle contraction arising from the central nervous system (CNS) [Fahn et al., 1986]. Myoclonus may be focal or generalized, single or repetitive, rhythmic or irregular. The CNS origin of myoclonus may involve the spinal cord, cortex, brain­stem, and cerebellum and provides the basis for several of many classifications of myoclonic movements [Serratosa and Delgado­Escueta, 1993]. Myoclonic phenomena include both nonepileptic (e.g., sleep myoclonus, opsoclonus-myoclonus, and narcotic­induced myoclonus) and epileptic myoclonus syndromes, such as juvenile myoclonic epilepsy or infantile spasms. This chapter presents the range of myoclonic events observed in neo­nates, infants, and children, distinguishes myoclonic seizure syndromes from other conditions, and provides practical guide­lines for the diagnosis and management of discrete types of myoclonic seizures.