A clinical and electroencephalographic study of 11 unrelated patients with Angelman syndrome (AS), confirmed by genetic analysis, is reported from the University of Pisa, Italy. All patients showed the jerky, tremulous, or dystonic motor pattern typical of AS. Using long-term video-EEG and polygraphic monitoring, these abnormal movements were shown to be a form of fast-bursting cortical myoclonus. Antimyoclonic treatment with piracetam in 5 patients produced a marked functional improvement. 
COMMENT. The diagnostic features of Angelman syndrome include ataxia, developmental delay, paroxysmal laughter, microcephaly, and seizures. The “puppetlike” movement disorder is related to a cortical myoclonus.