PUB - Publikationen an der Universität Bielefeld

Purpose: Complaints pertaining to memory functioning are among the most often reported cognitive symptoms in patients with epilepsy. However, research suggests a considerable mismatch between patients’ perception of memory functioning and the objective performance as measured with standardized neuropsychological tests. Depressive mood might be an important factor in explaining this discrepancy. As a new approach, the present study aimed to quantify the mismatch between subjective and objective memory functioning by considering the dynamic change of these factors as well as depressive symptoms after epilepsy surgery. Moreover, their influence on the overall quality of life was investigated. Methods: Pre- and postoperative (24 months) data from 78 patients with focal epilepsy (28% extratemporal) were retrospectively analyzed. Data from standard neuropsychological assessment included verbal memory capacity and self-ratings of subjective memory, depressive symptoms, as well as quality of life. Results: The results showed that (1) patients with clinically relevant postoperative depressive symptoms underestimate their actual memory performance; (2) the relationship between objective memory change and quality of life is mediated by the factors subjective memory change and depressive mood. Conclusion: Our data demonstrate a quantitative approximation of a pronounced depression-related negative bias in self-perception of memory functioning of roughly 1 to 1.5 standard deviations. At the same time, our data indicate that patients’ perceptions of memory functioning can be quite accurate in the absence of depressive symptoms. Additionally, subjective perception of memory performance and depressive mood may critically determine if objective memory changes contribute to patients’ postoperative QoL. Taken together, our study highlights the clinical relevance of incorporating subjective measures of memory functioning and mood that go beyond objective memory performance for the interpretation of how changes in memory functioning may affect patients’ quality of life after epilepsy surgery.