Validity and reliability of physical activity measures in multiple sclerosis.

PURPOSE: The purpose was to evaluate the psychometric properties of physical activity measures in persons with multiple sclerosis (PwMS). METHODS: Adults with multiple sclerosis were recruited, n = 30 (validation) and n = 57 (test-retest). Steps measured with PiezoRX, Yamax SW200 and ActiGraph GT9X Link (AGlink) and time in different positions measured with AGlink were validated against data from video analysis. Psychometric properties of the Physical Activity and Disability Survey - Revised Swedish version (PADS-R(Sw)) was evaluated. RESULTS: The most valid measures were AGlink using the low-frequency extension filter, and PiezoRX with median absolute percentage errors (MeAPEs) of 0.9-3.1% and 1.3-3.3%. The MeAPEs were higher for Yamax SW200 (2.9-21.0%), AGlink display (3.6-44.8%) and AGlink normal filter (8.9-48.9%), indicating low validity. AGlink was not valid in measurements of sitting (MeAPE 12.0-12.5%) or lying (MeAPE 31.0-41.7%). The correlation between PADS-R(Sw) and AGlink steps was r = 0.492 (p = .009). The relative reliability of PADS-R(Sw) was ICC2,1 0.85 (CI 0.76-0.91), and absolute reliability was SEM 0.54. CONCLUSION: AGlink and PiezoRX were valid measures of steps in PwMS. The questionnaire PADS-R(Sw) was valid, with high relative reliability, but its absolute reliability was unsatisfactory.

Reliability of the Swedish version of the Exercise Self-Efficacy Scale (S-ESES): a test-retest study in adults with neurological disease.

OBJECTIVE: To examine the test-retest reliability of the Swedish translated version of the Exercise Self-Efficacy Scale (S-ESES) in people with neurological disease and to examine internal consistency. DESIGN: Test-retest study. SUBJECTS: A total of 30 adults with neurological diseases including: Parkinson's disease; Multiple Sclerosis; Cervical Dystonia; and Charcot-Marie-Tooth disease. METHOD: The S-ESES was sent twice by surface mail. Completion interval mean was 16 days apart. Weighted kappa, intraclass correlation coefficient 2,1 [ICC (2,1)], standard error of measurement (SEM), also expressed as a percentage value (SEM%), and Cronbach's alpha were calculated. RESULTS: The relative reliability of the test-retest results showed substantial agreement measured using weighted kappa (MD = 0.62) and a very high-reliability ICC (2,1) (0.92). Absolute reliability measured using SEM was 5.3 and SEM% was 20.7. Excellent internal consistency was shown, with an alpha coefficient of 0.91 (test 1) and 0.93 (test 2). CONCLUSION: The S-ESES is recommended for use in research and in clinical work for people with neurological diseases. The low-absolute reliability, however, indicates a limited ability to measure changes on an individual level.