Abstracts

RATIONALE:During presurgical evaluation of epilepsy, ictal neuropsychological assessment can provide valuable localizing information regarding seizure onset and spread. Due to the short duration of an ictal event, a time-saving yet valid assessment is required. The present study examined the localizing value of ictal impairment of the following behavioral functions: orientation reflex, memory, consciousness, expressive and receptive speech. METHODS: A retrospective visual analysis of 116 focal seizure was performed. Ictal EEG (n = 40) or ECoG (n = 76) recordings demonstrated temporal seizure activity in 87 seizures and frontal seizure activity in 29 seizures. Comparisons between the frequencies of impairment of behavioral functions were calculated for patients with right temporal, left temporal, bitemporal and frontal seizure activity. In addition, using configuration-frequency analysis, a profile analysis of the variables orientation reflex, expressive and receptive speech was performed. RESULTS: The orientation reflex was significantly more frequently impaired in bitemporal or frontal lobe than in unilateral temporal seizures. Expressive speech was well preserved only in right temporal seizures. Memory and consciousness were most frequently lost with bitemporal seizure activity. Profile analysis demonstrated the occurence of intact receptive speech, but loss of expressive speech and orientation reflex most frequently in frontal seizures. All three functions were lost with bitemporal seizure activity but not impaired with right temporal seizure activity. Patients with left temporal seizure activity showed a preserved orientation reflex combined with loss of both speech functions. CONCLUSIONS: A separate consideration of impairment of behavioral subfunctions provides unambiguous localizing information only for the functions of consciousness and memory. Examination of the performance profile of the remaining three functions, however allows a discrimination of all examined patient groups. Hence, a time-saving yet valide ictal neuropsychological assessment should evaluate at least orientation reflex, expressive and receptive speech.