Two brothers who developed recurrent attacks of alternating hemiplegia arising out of sleep, distinguishable from classical alternating hemiplegia of childhood (AHC), are reported from Montreal Neurological and Children’s Hospitals, and Children’s Hospital of Western Ontario, London, ON, Canada. Both infants awoke screaming 1 1/2 hrs after falling asleep and were paralyzed on one side. After returning to sleep and awakening in the morning, they had recovered. Similar episodes recurred with increasing frequency. Features such as hypotonia, dystonia, and eye movements, characteristic of AHC, were absent. Development remained normal. Both parents had migraine. 
COMMENT. This apparently benign, familial form of alternating hemiplegia adds one more variety to the growing list of alternating hemiplegias of childhood. It is distinguished from the more common sporadic, classic form of AHC with a poor prognosis.