Background: Fatigue is one of the significant problems of post-stroke patients as it causes a decreased quality of life. Although the fatigue impact scale (FIS) is used in stroke, it lacks validation studies.
Objective: This study evaluates the psychometric properties of the FIS in patients with stroke.
Subjects and methods: A total of 41 subjects with stroke and 41 control subjects admitted to Physical Medicine and Rehabilitation Department were included. Convergent validity was assessed using the SF-36 vitality (SF-36 v) scale and the fatigue severity scale (FSS). Divergent validity was assessed using the Hospital Anxiety and Depression Scale (HADS).
Results: All subscores of the FIS were significantly higher in the stroke group than in the control group (p < .05). FIS showed excellent internal consistency in stroke patients (Cronbach's alpha = 0.946). There was a negative correlation among FIS and SF-36 v (r = -0.506, p = .001), and a positive correlation between the HADS anxiety score (r = 0.356, p = .026) and the HADS depression score (r = 0.293, p = .071). FIS total scores were weakly correlated with the FSS (r = 0.323, p = 0.039). The test-retest reliability of FIS was good in terms of its cognitive, physical, and psychosocial subscales and total scores, with ICC values of 0.78, 0.73, 0.80, and 0.83, respectively.
Conclusion: FIS is a valid and reliable multidimensional scale that sensitively discriminated fatigue in the stroke patients from that in the control subjects.
Keywords: Fatigue; fatigue impact scale; psychometric feature; stroke; validity and reliability.