Fatigue after stroke: the development and evaluation of a case definition.

OBJECTIVE

While fatigue after stroke is a common problem, it has no generally accepted definition. Our aim was to develop a case definition for post-stroke fatigue and to test its psychometric properties.

METHODS

A case definition with face validity and an associated structured interview was constructed. After initial piloting, the feasibility, reliability (test-retest and inter-rater) and concurrent validity (in relation to four fatigue severity scales) were determined in 55 patients with stroke.

RESULTS

All participating patients provided satisfactory answers to all the case definition probe questions demonstrating its feasibility For test-retest reliability, kappa was 0.78 (95% CI, 0.57-0.94, P<.01) and for inter-rater reliability kappa was 0.80 (95% CI, 0.62-0.99, P<.01). Patients fulfilling the case definition also had substantially higher fatigue scores on four fatigue severity scales (P<.001) indicating concurrent validity.

CONCLUSION

The proposed case definition is feasible to administer and reliable in practice, and there is evidence of concurrent validity. It requires further evaluation in different settings.