Evaluation of fatigue scales in stroke patients.

BACKGROUND AND PURPOSE

There is little information on how to best measure poststroke fatigue. Our aim was to identify which currently available fatigue scale is most valid, feasible, and reliable in stroke patients.

METHODS

Fatigue scales were identified by systematic search, and the 5 with the best face validity were identified by expert consensus. Feasibility (ie, did patients provide answers?) and internal consistency (an aspect of reliability) of these scales were evaluated by interviewing 55 stroke patients. Test-retest reliability was assessed by reinterviewing 51 patients, interrater reliability was assessed by rerating audio recordings, and convergent validity was assessed by measuring the correlation between scale scores.

RESULTS

Of the 52 scales identified, the SF-36v2 (vitality component), the fatigue subscale of the Profile of Mood States, the Fatigue Assessment Scale, the general subscale of the Multidimensional Fatigue Symptom Inventory, and the Brief Fatigue Inventory had the best face validity. The Brief Fatigue Inventory was unfeasible to administer and was omitted. Of the remaining 4 scales, the Fatigue Assessment Scale had the poorest internal consistency. Test-retest reliability for individual scale questions ranged from fair to good; the Fatigue Assessment Scale had the narrowest limits of agreement for the total score, indicating the best test-retest reliability. Interrater reliability for individual questions ranged from good to very good, and there was no significant mean difference in total scores for any scale. Convergent validity was moderate to high for the total scores of the 4 scales.

CONCLUSIONS

All four scales were valid and feasible to administer to stroke patients. The Fatigue Assessment Scale had the best test-retest reliability but the poorest internal consistency.