Relevance of Quality of Life Assessment for Multiple Sclerosis Patients with Memory Impairment

Background: Memory disturbances, in particular episodic verbal memory dysfunction, are the most frequent cognitive impairment observed in multiple sclerosis (MS) patients. The use of self-reported outcomes for evaluating treatment and managing care of these subjects has been questioned. The aim of this study was to provide new evidence about the suitability of self-reported outcomes for use in this impaired population by exploring the internal structure, reliability and external validity of a specific quality of life (QoL) instrument, the Multiple Sclerosis International Quality of Life questionnaire (MusiQoL). Methods: Design: cross-sectional study. Inclusion criteria: MS patients of any disease subtype. Data collection: sociodemographic (age, gender, marital status, education level, and occupational activity) and clinical data (MS subtype, Expanded Disability Status Scale, disease duration); QoL (MusiQoL and SF36); and memory performance (Grober and Buschke test). In accordance with the French norms of the memory test, non-impaired and impaired populations were defined for short- and long-delay free composites and for short- and long-delay total composites. For the 8 populations, psychometric properties were compared to those reported from the reference population assessed in the validation study. Principal Findings: One hundred and twenty-four consecutive patients were enrolled. The analysis performed in the impaired populations showed that the questionnaire structure adequately matched the initial structure of the MusiQoL. Th