Cognitive impairments in patients with intractable temporal lobe epilepsy

Abstract

Background: Cognitive impairment associated with temporal lobe epilepsy (TLE) has been recognized in multiple studies. We designed this study to find a specific cognitive profile in patients with TLE who were candidates for epilepsy surgery. We also sought to find if neuropsychological assessment could differentiate left TLE, right TLE and normal subjects.

Methods: The sample of this study consisted of 29 patients with right TLE, 31 with left TLE, and 32 subjects without history of seizure as the control group. For all recruited patients and controls, demographic questionnaire, Wechsler Memory Scale-III (WMS-III) and Wechsler Adult Intelligence Scale-R (WAIS-R) were administered. Multivariate analysis of variance was carried out to reveal differences in memory and intelligence performance between the three groups.

Results: All of the mean scores of the WMS-III indexes were significantly higher in the control group in comparison with the right or the left TLE groups (p < 0.001). There were not any significant differences between mean scores of WMS-III indexes of the right and the left. The WAIS-R also showed significantly better mean scores of full scale intelligence quotient (FSIQ) and performance intelligence quotient (PIQ) in the control groups than both of the right and left TLE patients (p < 0.001). Although the verbal intelligence quotient (VIQ) mean scores were significantly different between the left TLE and the control group (p = 0.037), there were not any significant differences between the right TLE patients and the control group.

Conclusions: These findings indicated that WMS-III and WAIS-R can differentiate patients with refractory temporal lobe epilepsy from normal subjects. However, the obtained cognitive profile could not differentiate between the right and the left TLE.

Keywords: Cognitive Impairment; Memory; Temporal Lobe Epilepsy; Wechsler Memory Scale.