Electrophysiological and auditory behavioral evaluation of individuals with left temporal lobe epilepsy

Abstract

The purpose of this study was to determine the repercussions of left temporal lobe epilepsy (TLE) for subjects with left mesial temporal sclerosis (LMTS) in relation to the behavioral testDichotic Digits Test (DDT), event-related potential (P300), and to compare the two temporal lobes in terms of P300 latency and amplitude. We studied 12 subjects with LMTS and 12 control subjects without LMTS. Relationships between P300 latency and P300 amplitude at sites C3A1,C3A2,C4A1, and C4A2, together with DDT results, were studied in inter-and intra-group analyses. On the DDT, subjects with LMTS performed poorly in comparison to controls. This difference was statistically significant for both ears. The P300 was absent in 6 individuals with LMTS. Regarding P300 latency and amplitude, as a group, LMTS subjects presented trend toward greater P300 latency and lower P300 amplitude at all positions in relation to controls, difference being statistically significant for C3A1 and C4A2. However, it was not possible to determine laterality effect of P300 between affected and unaffected hemispheres. Key words: epilepsy, event-related potentials P300, mesial temporal sclerosis.Avaliação eletrofisiológica e comportamental da audição em individuos com epilepsia em lobo temporal esquerdo resumo O objetivo deste estudo foi determinar a repercussão da epilepsia de lobo temporal esquerdo (LTE) em indivíduos com esclerose mesial temporal esquerda (EMTE) em relação à avaliação auditiva comportamental-Teste Dicótico de Dígitos (TDD), ao Potencial Evocado Auditivo de Longa Latência (P300) e comparar o P300 do lobo temporal esquerdo e direito. Estudamos 12 indivíduos com EMTE (grupo estudo) e 12 indivíduos controle com desenvolvimento típico. Analisamos as relações entre a latência e amplitude do P300, obtidos nas posições C3A1,C3A2,C4A1 e C4A2 e os resultados obtidos no TDD. No TDD, o grupo estudo apresentou pior desempenho em relação ao grupo controle, sendo esta diferença estatisticamente significante em ambas as orelhas. Para o P300, observamos que em seis indivíduos com EMTE o potencial foi ausente. Para a latência e amplitude, verificamos que estes indivíduos apresentaram uma tendência ao aumento da latência e redução da amplitude para todas as posições em relação ao grupo controle, sendo estatisticamente significante em C3A1 e C4A2. Contudo, não foi possível determinar efeito de lateralidade do P300 entre o hemisfério afetado e não-afetado. Palavras-chave: epilepsia, potencial evocado P300, esclerose mesial temporal.

Temporal resolution in individuals with neurological disorders

“…This result suggests that the neural function of MTS patients does not contribute the neural synchrony necessary for the detection of subtle electrophysiological events. This finding was further supported by studies showing electrophysiologic abnormalities in event-related potentials (ERPs) recorded from patients with MTS 29 , which were not observed using a similar paradigm in the visual modality 30 .…”

Auditory event‐related potentials (P300) and mesial temporal sclerosis in temporal lobe epilepsy patients

“…Our results are in accordance with previous studies with centrally recorded P300s (Fukai et al ., ; Chen et al ., ; Rocha et al ., ). Other studies have focused on limbic P300, showing reduced amplitudes and prolonged latencies, which is similar to our findings for centrally recorded P300 (Puce et al ., ; Nelson et al ., ; Psatta and Matei, ; Grunwald et al ., ; Rocha et al ., ). A possible explanation for a diffuse P300 disturbance is the presence of a diffuse‐projecting P300 generator, most likely also involving temporal regions of the brain (Polich, ; Duncan et al ., ).…”

The influence of (central) auditory processing disorder on the severity of speech-sound disorders in children

“…Individuals with cortical lesions outside the temporal lobe do not exhibit inferior performance on the DD Test compared with control groups 30 . Studies on patients with temporal lobe epilepsy have also indicated a worse performance on the DD Test in both ears compared with control groups 31 , 32 . These studies demonstrate the importance of the temporal lobe in sound processing during a dichotic task.…”