Measurement properties of the multifactorial memory questionnaire for evaluating subjective memory in people with epilepsy.

OBJECTIVE: This study aimed to investigate the measurement properties of the Multifactorial Memory Questionnaire (MMQ) for community-dwelling adults with epilepsy. METHODS: In phase one, 24 adults with epilepsy participated in semi-structured interviews to appraise the content validity of the MMQ. In phase two, adults with epilepsy (n = 290) completed a cross-sectional survey that evaluated structural validity (confirmatory factor analysis), internal consistency (Cronbach's Alpha and McDonald's Omega), and construct validity (hypothesis testing). A subset of these participants (n = 121) completed a second survey 4 weeks later to assess test-retest reliability (intraclass correlation coefficient) and measurement error (smallest detectable change and Bland-Altman Limits of Agreement). A priori criteria were set based on established criteria for good measurement properties. RESULTS: Adults with epilepsy deemed the MMQ to be relevant, comprehensive and comprehensible except for concerns about the appropriateness of the two-week recall period. Structural validity was partially supported: while the four-factor model fit best, only the SRMR met the a priori criterion. Internal consistency and test-retest reliability were sufficient, consistently exceeding the recommended threshold of ≥ 0.70. Measurement error parameters are reported to guide clinicians and researchers in interpreting changes in MMQ scores with repeated assessments. Construct validity was sufficient, with 90% of a priori hypotheses supported. CONCLUSIONS: As a comprehensive measure for evaluating subjective memory concerns in adults with epilepsy, the MMQ has demonstrated promising psychometric properties. However, future studies should clarify the dimensionality of the MMQ in this population and address measurement error, which could limit its utility in monitoring individual patients.