Twelve patients with perinatal anoxic encephalopathy, 1 with encephalitis, and 1 with Down's syndrome had startle epilepsy. Hemiparesis, startle-induced seizures involving the hemiparetic side, focal electroencephalographic abnormalities, and unilateral lesions evident on computed tomographic scan were found in 6 patients, all of whom responded favorably to carbamazepine. The remaining 8 patients had severe intellectual impairment, bilateral motor deficits, generalized startle-induced seizures, diffuse and lasting electroencephalographic abnormalities, and widespread cerebral lesions evident on computed tomographic scan. Of these, 2 patients with Lennox-Gastaut syndrome responded to clonazepam, 4 others responded to valproic acid, and 2 others, with predominantly focal hemispheric lesions, improved on a regimen of carbamazepine.

We describe a family and three sporadic cases of startle disease, or hyperekplexia. Sudden unexpected noises caused the patients to fall rigidly, often injuring themselves but retaining consciousness. This unusual entity differs from startle epilepsy and cataplexy. Clonazepam proved ineffective in three patients. Valproic acid, 5-hydroxytryptophan, or piracetam markedly reduced the abnormal startle in three patients.

In six cases of reflex epilepsy, the seizures were triggered by reading or elaborating a verbal utterance, and were accompanied on EEG by focal or generalized epileptiform activity. The seizures were controlled with clonazepam in four cases and by sodium valproate in two cases. We speculate that the disturbance has a cortical origin and is triggered by neural processes involved in the elaboration of language.

We describe the clinical features of a family with photosensitive epilepsy, followed for 13 years. Generalized paroxysmal discharges induced by photic stimulation appeared in all 9 siblings. Generalized seizures, myoclonic jerks, and absences appeared in variable combination in 7 of them who on clonazepam remained free from seizures for a seven-year follow-up period. On EEG the paroxysmal abnormalities induced by photic stimulation abated during clonazepam medication.