Ictal clinical electroencephalographic findings of spasms in West syndrome

Epilepsia. Jul-Aug 1993;34(4):671-8. doi: 10.1111/j.1528-1157.1993.tb00445.x.


The electroencephalographic/video recordings of 955 spasms in children with cryptogenic and symptomatic West syndrome (WS) were reviewed to define the relation between a clinical manifestation of a spasm and its EEG pattern, and to examine whether these features reflect the etiology and prognosis of WS. The review confirmed the spasm to be a distinct type of seizure, with a unique clinical and EEG pattern unlike that of all other recognized seizures. Symmetric spasms were present in cryptogenic and symptomatic patients. In contrast, asymmetric spasms, or focal signs recognizable during a spasm, strongly indicated the existence of a cerebral lesion. In both etiological groups, the characteristic ictal EEG pattern of the spasms consisted of a positive-vertex slow wave. The other two patterns apparently correlated to a spasm, were fast activity, here called spindle-like, and decremental activity. The fast activity corresponded to a clinical stare, and the decremental activity, when present, represented a postictal event. Although it was independent from the etiology of the spasms, persisting hypsarrhythmia during a cluster of spasms appeared to be an EEG pattern that correlated with a favorable outcome.

MeSH terms

  • Electroencephalography*
  • Electromyography
  • Humans
  • Infant
  • Muscle Contraction
  • Prognosis
  • Spasm / diagnosis
  • Spasms, Infantile / diagnosis*
  • Spasms, Infantile / etiology