Factors influencing poststroke subjective fatigue – The issue of a bidirectional relationship between fatigue and functional outcome

Objective: Subjective fatigue is a common symptom after stroke. So far however it is unclear which factors play a major role for its occurrence. We examined possible factors which influence poststroke subjective fatigue in the acute phase of the stroke and after three months, considering factors like age, living situation, neurological and psychological variables. In addition the impact of subjective fatigue for the functional outcome was assessed.

Methods: Data were obtained prospectively from 35 patients with first-ever stroke in the acute phase and in a three months follow-up. The relationship between subjective fatigue (Checklist Individual Strength (CIS)) and age, living situation, perceived personal control (Recovery Locus of Control Scale (RLOC)), depression and anxiety (Hospital Anxiety and Depression Scale (HADS)), speed of mental processing (Trail Making Test Part A (TMT-A) and executive functions (Trail Making Test Part B (TMT-B)), cognitive impairment (Mini-Mental State Examination MMSE)) and neurological deficits (National Institute of Health Stroke Scale (NIHSS)) was examined. Furthermore it was examined if subjective fatigue patients had different aetiology (Trial of Org 10172 in Acute Stroke Treatment- (TOAST)-classification) respectively different lesion sites and their clinical deficits (Oxfordshire Community Stroke Project (OCSP)-classification).

Linear regression models were used to derive predictive factors for functional outcome and subjective fatigue, taking the Functional Independence Measure (FIM) and the CIS-fatigue as outcome variable.

Results: Subjective fatigue (CIS greater or equal to 40) was reported from 12 (34%) patients in the acute phase and from 17 (45%) patients three months poststroke. Subjective fatigue can predict functional outcome (p=0.012). On the other hand functional outcome also predicts subjective fatigue in the acute phase (p=0.01) and three months poststroke (p=0.035). Other predictors of subjective fatigue in the acute phase are cognitive impairment (p=0.021) and after three months anxiety (p=0.003).

Conclusion: Subjective fatigue is already frequently present in the acute phase of stroke. A reciprocal relationship between subjective fatigue and functional outcome exists in the acute phase. Other variables related to subjective fatigue are cognitive impairment in the acute phase and anxiety after three months. These data indicate that subjective fatigue may have various causes changing during the time course of recovery.