primary generalised epileptic seizures occurring in infants between birth and twelve months of age consisting of brief synchronous contractions of the neck, torso, and both arms. These seizures often occur in infants with underlying neurologic diseases. The prognosis for these infants is grave, with approximately ninety percent developing mental retardation in addition to their seizures. The eeg has a typical hypsarrhythmia pattern. The spasms and hypsarrhythmia have a tendency to disappear over the first three to five years of life, only to be replaced by other forms of generalised seizures. Infantile spasms sometimes respond to valproic acid or acth.