Objectives: To assess the validity and reliability of the multidimensional, self-administered Multiple Sclerosis International Quality of Life (MusiQoL) questionnaire, previously validated in a large international sample, in Norwegian patients.
Patients and methods: Patients with different types and severities of multiple sclerosis (MS) were recruited from a single MS centre in Norway. All patients completed the MusiQoL and Short Form-36 (SF-36) QoL questionnaires at baseline and a mean of 21 (SD 7) days later. A neurologist collected sociodemographic, MS history and outcome data. Construct validity, internal consistency, reproducibility and external consistency were tested.
Results: One hundred and four patients were evaluated. Construct validity was confirmed in terms of satisfactory item internal consistency correlations in eight of nine MusiQoL dimensions (Spearman's correlation: 0.34-0.79) and scaling success of item discriminant validity (75.0-100%). All dimensions of the MusiQoL questionnaire exhibited satisfactory internal consistency (Cronbach's alpha: 0.44-0.87) and reproducibility (intraclass correlation coefficients: 0.36-0.86). External validity testing showed that the global MusiQoL score correlated significantly with all but one individual SF-36 dimension score (Spearman's correlation: 0.29-0.56).
Conclusions: These results demonstrate that the Norwegian-language version of the MusiQoL questionnaire is a valid and reliable instrument for assessing health-related QoL in Norwegian patients with MS.
© 2011 John Wiley & Sons A/S.