Cognitive assessment in an epilepsy clinic using the AD8 questionnaire

Abstract Objective This study examined cognitive function in patients with epilepsy using the AD8 screening questionnaire to assess the frequency of, and factors associated with, cognitive impairment in these patients. Method The AD8 screening questionnaire for cognitive impairment was administered to one hundred consecutive patients diagnosed with epilepsy who attended a dedicated epilepsy clinic based in a tertiary care neuroscience center. Where possible, accompanying informants also completed AD8 on behalf of the patient. Results Forty-eight percent of patients in this cohort scored above the AD8 cutoff (higher scores are considered worse) for cognitive impairment. Categorizing patient groups by AD8 score showed no difference (null hypothesis not rejected) in patient age, new or follow-up appointment, epilepsy type (partial/generalized), or treatment (monotherapy/polytherapy), but a significant difference (null hypothesis rejected) was found for disee duration, with those scoring above the AD8 cutoff having a significantly longer disease duration. There was no correlation between AD8 scores and patient age but a weak positive correlation with disease duration. AD8 questionnaires completed by informants showed a similar frequency of cognitive impairment (54%), and patient:informant AD8 scores showed substantial agreement beyond chance. Conclusions AD8 is acceptable to patients with epilepsy and their informants for the assessment of cognitive function. In this dedicated epilepsy clinic, its use suggested a high frequency of cognitive impairment in both self-rating and informant assessments. A less sensitive, more specific cognitive screening instrument (CSI) might be more desirable in this population. Duration of epilepsy or some factor related to it may contribute to cognitive symptoms.