Abstracts

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is characterized by the occurence of prolonged hemiclonic seizures followed by the development of hemiplegia, typically in the course of a febrile illness before 4 years of age. Following a variable interval (mean 1-2 years), subsequent epilepsy develops, most frequently with complex partial seizures. The motor deficit has a variable course, with some patients continuing to exhibit a definitive hemiplegia while others show complete resolution. Cognitive outcome following HHE has been poorly studied, although early descriptions reported that mental retardation was a common feature. Furthermore, little attention has been paid to the implications of side of involvement in HHE. The purpose of the current study was to evaluate speech lateralization and cognitive performance in patients with left- and right-sided HHE. Data from eight patients were examined. Mean ages were 31.4 and 29.7 years for the right (n=5) and left (n=3) hemiparetic groups, respectively. All patients had their hemiconvulsive seizures before age 2 years. Age of habitual seizure onset ranged from 1.5 to 12 years. Speech lateralization was examined using intracarotid amobarbital testing (IAT) for the right hemiparetic group and dichotic words for the left group. Performance on tests of intelligence, verbal memory, and visual memory was also examined. IAT indicated atypical speech representation (right hemisphere or bilateral) in 4/5 of the right hemiparetic patients. Intellectual functioning in this subgroup was in the Borderline to Extremely Low range. These patients also obtained impaired or variably impaired scores on measures of verbal and visual memory. The one left hemisphere speech dominant patient in this group performed in the average range on tests of intellectual functioning and verbal memory, while scores on visual memory were variable. IAT was not performed with the left hemparetic patients. However, results from dichotic listening suggested left hemispheric speech representation in all three patients. Intellectual functioning was average in two patients, and in the Borderline range in one patient. Verbal and visual memory were largely intact in the left hemiparetic group, with most scores falling in the average range. Atypical speech representation was common in patients with right hemiparetic HHE (involving the left hemisphere). This was associated with generally poor cognitive outcome as evidenced by intelligence and memory test scores. The one patient with left speech representation demonstrated the best cognitive performance of the group. Left hemiparetic HHE was associated with lower probability of adverse cognitive sequelae and no evidence of atypical speech representation. The broad range of impairment in the right hemiparetic group may be related to the shift of language to the right hemisphere, although other factors (e.g., severity and age of HHE episode) may also contribute to cognitive outcome.