Cognitive impairment in epilepsy patients and its correlations

Epilepsy is a severe disease in which seizures play the leading role. Striking clinical manifestations of the attacks take most of the attention of healthcare professionals. Apart from epilepsy itself, it is well known that epilepsy patients may also have psychiatric comorbidities. These disorders, such as anxiety and depression, are mostly thought to be related to epileptic seizures or antiepileptic medications. In clinical practice, cognitive impairment is another disrupted area of interest in epileptic patients. Our study aimed to detect this deterioration and its correlations with mood disorders and epileptic disease features such as seizure frequency and illness duration.

After obtaining verbal and written consent, we enrolled 52 epilepsy patients in our study. A short demographic form indicating their gender, epileptic disease features, and medication usage information was completed for each patient. The Quick Mild Cognitive Impairment Screen (QMCI) test, the Hamilton Anxiety Rating Scale (Ham-A), and the Hospital Anxiety and Depression Scale (HADS) were applied by an experienced psychologist. Abnormal brain magnetic resonance imaging findings (e.g., encephalomalacia, large arachnoid cysts, a considerable amount of white matter gliotic lesions, neoplastic or vascular space-occupying lesions, hippocampal malformations), vitamin and electrolyte imbalances, other chronic diseases as well as thyroid dysfunction were considered as exclusion criteria since they might interfere with cognition. We excluded abnormalities to this extent because we wanted to acquire a homogenous sampling population without structural disadvantages. Thus, we could be able to determine slight changes in cognition properly.

We found decreased cognitive scores directly proportional to lower education level, higher seizure frequency, longer disease duration, generalized tonic-clonic (GTC) type of seizure, and antiepileptic polytherapy. Also, complying with the literature, a high frequency of depression was found in our study group. Interestingly, decreased anxiety levels of the patients were statistically related to higher seizure frequency, which may indicate adaptive mechanisms to frequent seizures. Finally, a multivariate regression analysis revealed a significant negative impact of GTC type of seizure on cognition.

Epilepsy and epileptic seizures affect cognition negatively. Thus, newly diagnosed epilepsy patients should be assessed for cognitive status as soon as possible. This assessment will allow epileptologists to understand future deteriorations in their patients' cognition. In our study, it is shown that QMCI is an effective and practical way to assess the cognitive statuses of epilepsy patients.