Asymmetric Hypsarrhythmia: Clinical Electroencephalographic and Radiological Findings

Ivo Drury, Ahmad Beydoun, Elizabeth A. Garofalo, Thomas R. Henry

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Summary: Twenty‐six children (16 boys and 10 girls) with hypsarrhythmia and infantile spasms (IS) were studied at the University of Michigan EEG Laboratory in a 4‐year period. Six (2 boys, 4 girls), had asymmetric hypsarrhythmia with a preponderance of both slowing and epileptic form activity over one hemisphere. All 6 had the symptomatic form of IS, 4 with dysplastic conditions, 1 with porencephaly from a cerebral infarct, and 1 with hypoxic‐ischemic encephalopathy. Five children had focal abnormalities on either physical examination or imaging studies. Four had the highest amplitude slowing and most epileptiform activity ipsilateral to the lesion, in 1, it was contralateral. Asymmetric hypsarrhythmia constituted 23% of cases with hypsarrhythmia examined at our EEG laboratory. The significant success in surgical therapy for some children with IS indicates the importance of identifying focal hemispheric abnormalities even if they are not apparent clinically. EEG may suggest focal changes not detected clinically or radiologically.

Original languageEnglish (US)
Pages (from-to)41-47
Number of pages7
Issue number1
StatePublished - Jan 1995


  • Asymmetric hypsarrhythmia
  • Cerebral dysgenesis–Therapeutic implications
  • Children
  • Infantile spasms Electroencephalographic criteria
  • Neuroimaging


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