Cognitive performance in cryptogenic epilepsy.

Cognitive impairment in epilepsy has begun to gain more attention in clinical practice. There is now a considerable amount of research relating to memory functioning in epilepsy, however, few studies specifically focused on cryptogenic epilepsy. We investigated the cognitive performance in cryptogenic epilepsy patients with the aid of cognitive ability screening instrument (CASI), based on cross-sectional and longitudinal aspects. A total of 100 patients who met the diagnostic criteria of cryptogenic epilepsy were recruited from a national university hospital. The patients with normal CASI scores were compared with those with abnormal ones. We also compared the follow-up CASI score after 3 years with the previous score in all cryptogenic epilepsy patients. Thirty-six per cent of cryptogenic epilepsy patients showed cognitive impairment. The variables correlated with higher risks of cognitive impairment were lower educational status, number of seizure types, duration of seizure and polytherapy, especially in the lower educational status. The correlation between CASI and the Mini-Mental State Examination was excellent. In the follow-up study, the abnormal group showed significant improvement in total CASI score. The normal group showed no significant change. We suggest that in cryptogenic epilepsy, lower educational status remains the most important factor in determining cognitive performance. Adequate treatment with antiepileptic drugs can improve cognitive performance in previously cognitively impaired patients.