Hyperekplexia: a syndrome of pathological startle responses

Ann Neurol. 1984 Jan;15(1):36-41. doi: 10.1002/ana.410150107.


We describe a family and three sporadic cases of startle disease, or hyperekplexia. Sudden unexpected noises caused the patients to fall rigidly, often injuring themselves but retaining consciousness. This unusual entity differs from startle epilepsy and cataplexy. Clonazepam proved ineffective in three patients. Valproic acid, 5-hydroxytryptophan, or piracetam markedly reduced the abnormal startle in three patients.

Publication types

  • Case Reports

MeSH terms

  • 5-Hydroxytryptophan / therapeutic use
  • Adolescent
  • Adult
  • Child
  • Female
  • Humans
  • Male
  • Nervous System Diseases / drug therapy
  • Nervous System Diseases / genetics
  • Nervous System Diseases / physiopathology*
  • Piracetam / therapeutic use
  • Reflex, Startle / drug effects
  • Reflex, Startle / physiology*
  • Valproic Acid / therapeutic use


  • Valproic Acid
  • 5-Hydroxytryptophan
  • Piracetam