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

BACKGROUND: 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. AIM: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Prevalence and clinical characteristics of malformations of cortical development and incomplete hippocampal inversion with medically intractable seizures in Chennai - A prospective study.

OBJECTIVE: To study the prevalence and clinical characteristics of malformation of cortical development (MCD) and incomplete hippocampal inversion (IHI) in adults with intractable seizures. MATERIALS AND METHODS: In this prospective study of 3220 epileptic patients in our epilepsy clinic between 2012 and 2014, 416 had intractable seizures. In all patients, a detailed clinical history, neurological examination, electroencephalography (EEG), computed tomography (CT) scan, magnetic resonance imaging (MRI) brain, and neuropsychological assessment was conducted to identify MCD and IHI. RESULTS: Out of 416 patients with intractable seizures, MCD and IHI were confirmed in 85 patients (48 males, 37 females). MCD was observed in 46 (11.05%) patients and IHI were observed in 39 (9.37%) patients. Chi square test revealed no signi cant difference between the MCD and IHI groups across the patients in different age groups, gender, type of seizure, duration and onset of seizure, seizure frequency, clustering, status epilepticus, EEG, febrile seizures, and family history. Statistically significant differences (P < 0.05) were observed between the MCD and IHI groups for change in seizure semiology and in intelligence quotient (IQ) and memory quotient (MQ) scores obtained using Wechsler's adult intelligence scale III and Wechsler's memory scale. The IHI group showed higher IQ and MQ scores when compared to the MCD group. Furthermore, IHI occurred along with MCD in 6.52% (N = 3) of the population. CONCLUSION: MCD and IHI patients are often associated with intractable complex partial seizures. Intractable epilepsy patients with normal intelligence and normal MRI should be investigated with hippocampal volumetric studies to identify the presence of IHI. Isolated IHI can be considered as a form of MCD because it mimics the clinical features of MCDs.