A cross-sectional study exploring overlap in post-stroke fatigue caseness using three fatigue instruments: Fatigue...

Post stroke fatigue (PSF) is a frequent symptom affecting 25-73% of stroke survivors. The variability in estimates of prevalence found across studies reflects differences in fatigue measures and use of different cut-offs for defining clinically significant fatigue. The main aim of this study is to explore the frequency and overlap in caseness of fatigue using three different fatigue measures in a sample of patients at 3 months post stroke. Furthermore, we wanted to explore the instrument's associations with demographic and clinical characteristics.

The sample consists of 93 patients with new onset stroke. This cross-sectional study includes three measurements of fatigue, The Fatigue Severity Scale (FSS), The Chalder Fatigue Questionnaire (FQ) and the Lynch Interview. Medical, physical, psychological data and estimates of pre-stroke fatigue were collected 3 months post stroke.

The FQ using the bimodal scoring yielded about 2.5 more fatigue cases (n = 57) than the FSS with a cut-off mean score of 5 (n = 22). The Lynch interview identified 48 patients as fatigue cases. Conducting multivariate analyses, the three instruments were differently associated with predictor variables such as prestroke fatigue, reduced balance and burden of symptoms reported post stroke.

The use of different instruments leads to a large variability in identifying fatigue cases in a sample of stroke patients. Scientifically and clinically a clarification and consensus on how to measure fatigue is warranted. Without correct identification of PSF-cases, knowledge about the causes of fatigue and development of tailored and interdisciplinary interventions are further delayed.