A 4 year old child who had complex partial seizures alternating with sleep that presented as episodic hypersomnolence is reported from the Mayo Clinic, Rochester, MN. The hypersomnolence lasting 24-72 hrs was preceded by irritability and hyperkinesia for 48-96 hrs. The intervals between episodes ranged from 10-60 days. The EEG showed left occipital spikes in sleep. Prolonged recording during hypersomnolence showed right temporal seizure discharges. Phenytoin controlled the episodic hypersomnolence, with no recurrence at 19 yr follow-up. Complex partial seizures followed by postictal somnolence occurred occasionally between 5 and 11 yrs of age. CT was normal. Behavioral problems required special education and methylphenidate. He graduated from high school and has a manual labor job. [1]

COMMENT. The EEG recording showing right temporal seizure discharges during the period of hypersomnolence. and the excellent response to phenytoin suggest that the episodic sleep disorder may be regarded as a seizure phenomenon. Lennox WG refers to “sleeplike episodes” and somnambulism as forms of epilepsy, but does not describe a case similar to the above report. (Epilepsy and Related Disorders. Boston, little, Brown, 1960).

A young man presented with episodes of unexplained hypersomnolence lasting 24-48 hrs in my own practice. An EEG between episodes showed occasional temporal sharp waves. CT and metabolic studies were normal. An EEG recording during an attack could not be obtained. A trial of phenytoin was successful in this case, and attacks recurred when treatment was discontinued. A seizure disorder was suspected but not proven.

Sleep disorders with central hypoventilation syndrome and seizures is reviewed in Progress in Pediatric Neurology II, Chicago, PNB Publ, 1994, pp 192-4.