Abstracts

To investigate auditory processing with cortical long-latency auditory evoked potentials (AEP) in patients with autosomal dominant lateral temporal lobe epilepsy (ADTLE). Eight patients with LGI1-related ADTLE belonging to a family with predominantly aphasic seizures were studied. Sixty-five individuals without epilepsy served as controls. AEP (N1-P2 amplitudes) to binaural tones were recorded over the left and the right hemisphere. Brainstem auditory evoked potentials (BAEP) to monaural rarefaction clicks were also analysed. Group differences were statistically assessed with student[apos]s t-test and repeated measures ANOVA. Left AEP amplitudes were moderately reduced in ADTLE patients (p=0.005). The left-right N1-P2 amplitude difference was significantly more negative in ADTLE patients compared to controls (p[lt]0.005). There were no group differences in BAEP amplitudes or latencies indicating unaffected cochlear system and auditory brainstem pathways. A moderate, but highly significant reduction in N1-P2 AEP amplitudes over the left hemisphere was demonstrated in patients with ADTLE. This finding corresponds to the cardinal symptom of aphasia in the present family, and also to the generally prevailing left-sided EEG abnormalities in this condition. The background for this electrophysiological lateralization in LGI1-related epilepsy is unknown. It may be related to a specific function of LGI1 in the dominant hemisphere.