Measuring fatigue and perceived exertion in rehabilitation

Background: Fatigue post stroke is a major issue, distressing to individuals and without any evidence based treatment. Impacts of fatigue on the amount of exertion possible in rehabilitation is not known, and this is problematic when rehabilitation requires high levels of activity to drive neuroplasticity. Aim: To validate an electronic tool to measure fatigue and exertion in people undergoing rehabilitation and describe the relationship between fatigue and exertion in this population. Methods: Thirty-three adults (78.1±10.8 years) undergoing rehabilitation participated in a randomised crossover trial measuring fatigue and exertion after a one-hour physiotherapist supervised exercise session. Participants completed a visual analogue scale for fatigue and BORG exertion on paper and electronically (using an iPad) in a randomised order. Validity for fatigue and exertion was measured using Bland Altman (limits of agreement and bias). Regressions analysis described relationships and Odds Ratio’s calculated. Results: For fatigue there was a small negative bias (± SD of bias) towards the iPad (-3.02 ± 6.57) with limits of agreement between -15.90 and 9.86. For exertion there was a small bias (± SD of bias) towards the iPad (0.03 ± 1.29) with limits of agreement between -2.49 and 2.55. No significant differences between iPad and paper for regression analysis. Although people with higher levels of fatigue reported higher levels of perceived exertion (OR 2.1; 95%CI 0.78 to 5.96), this result was not statistically significant (p=0.14). Conclusion: Using electronic data collection tools to measure fatigue and exertion in clinical populations is valid. Further research to investigate the relationship between fatigue and perceived exertion is warranted.