The relationship between memory performance, perceived cognitive function,and mood in patients with epilepsy

Objective: The low correlations between memory performance and subjective m emory may be attributable to disparities between tasks in neuropsychologica l tests and cognitive experiences of day-to-day living. This study evaluate d the relationship between everyday memory performance, perceived cognitive functioning, and mood among patients with epilepsy. Methods: From three ep ilepsy centers in the USA, 138 patients were recruited. Everyday memory per formance was measured using the Rivermead Behavioural Memory Test (RBMT). Q uestionnaires assessed perceived cognitive function (cognitive domain, Qual ity of Life in Epilepsy Inventory, QOLIE-89) and mood (Profile of Mood Stat es, POMS). Results: Memory performance scores were weakly correlated with p erceived cognitive functioning (r = 0.22, P < 0.01). Perceived cognitive fu nctioning was strongly correlated with mood (r = -0.75, P < 0.0001). Multip le regression analysis indicated memory performance (RBMT) and mood (POMS) were independent predictors of perceived cognitive functioning (P < 0.02); however, the explained variance for RBMT and POMS combined (R-2 = 0.58) is only slightly higher than the predictive value for the POMS score alone (R- 2 = 0.56). Conclusions: Memory performance tests provide qualitatively diff erent information than patients' self-reported cognitive difficulties, thus it is important to assess memory performance, perceived cognitive function , and mood separately because the constructs are related but not redundant. (C) 1999 Elsevier Science B.V. All rights reserved.