Evaluation of Cognitive Impairment in Refractory Temporal Lobe Epilepsy Patients With Respect to Structural Brain Lesions

Abstract

Introduction: Temporal lobe epilepsy (TLE) is the most prevalent form of drug resistant epilepsy with concurrent cognitive impairment. Prevention, earlier diagnosis, and personalized management of cognitive deficits in TLE require more understanding of underlying structural and functional brain alterations. No study has evaluated performance of TLE patients in different cognitive domains based on their structural brain lesions. Methods: In this study, 69 refractory TLE patients have undergone magnetic resonance imaging (MRI) epilepsy protocol and several neuropsychological tests, consisting of Wechsler adult intelligence scale-revised, Rey-Osterrieth complex figure test, verbal fluency test, digit span test, spatial span test, Wechsler memory scale-III, design fluency test, Rey visual design learning test, auditory-verbal learning test, and trail making test. MRI findings were classified to following groups: focal cortical dysplasia, gliosis, atrophy, mesial temporal sclerosis (MTS), tumor, vascular malformation, and other lesions or normal. Results of neuropsychological tests were compared between MRI groups using generalized linear model with gamma distribution and log link. Results: Patients with MTS showed better performance in general intellectual functioning, working memory, attentional span, and auditory-verbal learning compared to patients with non-MTS MRI lesions. Atrophy and focal cortical dysplasia had the largest differences from MTS. Conclusion: Cognitive performance of refractory TLE patients varies with respect to structural brain alterations. Further neuroimaging studies of TLE lead to prevention and more accurate management of cognitive decline in clinical settings.