Subclinical delta status in the newborn--an unfavorable prognostic sign.

A hitherto undescribed, unusual EEG abnormality invariably associated with a poor prognosis was reported and was called subclinical delta status. It consisted of continuous discharges of high voltage monomorphic or polymorphic delta activity occurring diffusely but often asynchronously in all leads, without sleep cycles. These discharges when monomorphic may be confused with respiratory artefacts, and when polymorphic they may be mistaken for part of the background activity. Four neonates with this abnormality all had intracranial bleeding and were mechanically ventilated because of frequent apneic attacks. Staring or deviation of the eyes was frequently observed during the EEG recording. A small dose of intravenous diazepam temporarily abolished this activity. Three infants died and the other survived with neurological sequelae.