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Updated: Aug 22, 2026
The Multiple Sclerosis Performance Test (MSPT): An iPad-Based Disability Assessment Tool
Published on: June 30, 2014
Test-retest reliability and convergent validity of the Fatigue Impact Scale for persons with multiple sclerosis
1Program in Occupational Therapy, Department of Physical Medicine & Rehabilitation, University of Minnesota, MMC 388, 420 Delaware Street SE, Minneapolis, Minnesota 55455, USA. mathi003@umn.edu
Objective:
The test-retest reliability and the convergent validity of the Fatigue Impact Scale (FIS) were evaluated using secondary data from 54 persons with multiple sclerosis (MS).
Methods:
This reliability and validity study used FIS data from before and after two control periods to evaluate test-retest reliability. Convergent validity of the FIS with the Fatigue Severity Scale and with subscales of the SF-36 Health Survey was evaluated using data collected before the first control period.
Results:
No significant differences between before and after FIS measurements and intraclass correlation coefficients ranging from .68 to .85 indicate that the FIS has good test-retest reliability except for the physical subscale. The expected moderate correlations between the FIS and several subscales of the SF-36 support its convergent validity. In contrast, the unexpected low correlation between the FIS and Fatigue Severity Scale does not support convergent validity.
Conclusion:
The FIS has adequate reliability and validity and is recommended to evaluate the effectiveness of fatigue management interventions such as energy conservation education for persons with MS.
