The relation between subjective and objective measures of everyday life activities in persons with multiple sclerosis

OBJECTIVES: To investigate the relation between subjective and objective performance-based measures of functional status in persons with multiple sclerosis (MS), and to compare their performance with healthy controls. DESIGN: A between-groups design, using a correlational approach to examine the relation between objective and subjective measures of functional capacity. SETTING: Outpatient rehabilitation research institution. PARTICIPANTS: Seventy-four subjects with clinically definite MS and 35 healthy controls. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Executive Function Performance Test (EFPT), Functional Assessment of Multiple Sclerosis (FAMS), and Functional Behavior Profile (FBP). RESULTS: MS participants reported more difficulties performing functional tasks than did the healthy controls. MS participants also performed significantly worse on the EFPT than healthy controls. However, all correlations between subjective and objective functional measures were nonsignificant. After controlling for depressive symptomatology, EFPT performance was significantly associated with FBP scores, but not FAMS scores. CONCLUSIONS: The lack of association between objective performance-based measures and subjective self-report measures of functional activities is a challenge to outcomes measurement and has implications for assessment of functional performance. Results are discussed in terms of the different dimensions that these tools are measuring and their respective strengths and limitations.