Involvement of Incomplete Hippocampal Inversion in Intractable Epilepsy: Evidence from Neuropsychological Studies.

Abstract

The age of onset of seizure, seizure types, frequency of seizure, structural abnormalities in the brain, and antiepileptic medication (polytherapy) causes increased incidence of anxiety and depression in intractable epilepsy patients. To compare the anxiety and depression levels in intractable epileptic patients with structural abnormalities [malformations of cortical development (MCD) and incomplete hippocampal inversion (IHI)] and without structural abnormalities. Participants were selected from (239 males and 171 females) intractable epilepsy patients. They were grouped into four groups; Group 1: 51 nonepileptic age-matched controls, Group 2: 41 intractable epilepsy patients without any brain abnormality, Group 3: 17 intractable epilepsy patients with MCD, and Group 4: 30 intractable epilepsy patients with isolated IHI. Neuropsychiatric tools used were Multiphasic Personality Questionnaire and Weschlers Adult Intelligence Scale to assess anxiety, depression, and intelligence. Groups were classified using 1.5T conventional magnetic resonance imaging and hippocampal volumetric studies. Group comparison design was used. Demographic variables of intractable epilepsy, including seizure types, the frequency of seizure, the age of seizure onset, and antiepileptic drug therapies, did not show significant association between the groups using Chi-square P value. Analysis of variance showed significant anxiety and depression in epileptic patients than the control group (P < 0.01). Post hoc analysis using Tukey's B test showed significant difference in anxiety and depression scores between group value. In group 3 and 4, anxiety scores were significantly different but not depression scores. The present study concludes high prevalence of anxiety and depression in intractable seizure. Anxiety is observed predominantly when there is IHI along with depression. We emphasize the need to identify IHI in intractable epilepsy and assess anxiety and depression to treat them effectively.