Jessica Bruijel, Annemiek Vermeeren, Nick N.J.J.M. van der Sluiszen, Stefan Jongen, Sven Z. Stapert, Caroline M. van Heugten
Department of Neuropsychology & Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, 6200 MD Maastricht, The Netherlands.
DOI: 10.2340/16501977-2766

Objective: To evaluate the construct validity of Psychomotor Vigilance Test performance for measuring fatigue in people with acquired brain injury.
Design: Observational cross-sectional study.
Participants: Fifty-four people with acquired brain injury and 61 healthy controls.
Methods: Participants performed the Psychomotor Vigilance Test and reported momentary fatigue before and after this test and general fatigue. Associations between performance and fatigue in patients were tested by correlational and hierarchical multiple linear regression analyses, controlling for sleep quality, daytime sleepiness, and mood.
Results: Patients performed worse on the test compared with controls. Within the patient group, worse test performance was associated with increases in momentary post-test fatigue and general fatigue, indicating convergent validity, but also with daytime sleepiness, and mood complaints, indicating a lack of divergent validity. When controlling for sleepiness and mood, the association between performance and general fatigue was no longer significant, whereas the association between performance and post-test fatigue remained.
Conclusion: Performance on the Psychomotor Vigilance Test cannot be used as a specific measure for fatigue, but it appears to be a more general measure of severity of symptoms including fatigue, mood, and sleepiness. Therefore, the Psychomotor Vigilance Test may be a useful measure to examine the effects of interventions aimed at reducing these symptoms.

Fatigue is a frequent symptom following acquired brain injury. Assessment is usually based on self-report, but additional objective measures are advised. The Psychomotor Vigilance Test has previously been found to be sensitive to the effects of acquired brain injury and performance on this test may relate to fatigue and sleepiness. This study examined whether Psychomotor Vigilance Test performance in peo-ple with acquired brain injury is associated with fatigue, after controlling for daytime sleepiness, sleep quality, and mood. The study found that performance on this test is related to fatigue, but also to sleepiness and mood. The Psychomotor Vigilance Test therefore cannot be used as a specific measure for fatigue, but could be used to measure changes or improvement of symptoms including fatigue, mood and sleepiness. The Psychomotor Vigilance Test thus has the potential to be implemented as an objective measure to evaluate these symptoms following acquired brain injury in both research and clinical practice.