The majority of patients with epilepsy are seizure-free, and repeated neuropsychological assessment may be highly relevant in this group. However, previous studies have not addressed the possible influence of important clinical variables on repeated neuropsychological assessment in this population.
Using data from a large antiepileptic drug (AED) withdrawal study, we calculated the neuropsychological practice effects for 139 seizure-free patients with epilepsy and analysed the influence of different epilepsy-related factors on improvement that were observable 7 months after the initial neuropsychological assessment.
A clear and significant improvement in neuropsychological test performance was found for all the tests employed, regardless of AED withdrawal. Furthermore, patients characterized by evidence of brain pathology, such as known cerebral aetiology, pathological MRI and pathological EEG, showed less practice effects than patients not characterized by these variables. The differences were primarily evident for measures of verbal learning and memory.
The data obtained from this study suggest that the development of general norms for change in the particular patient population, as well as specific norms for change related to important clinical variables, might be necessary to be able to determine whether genuine neuropsychological changes have occurred in individual patients in this group.