Objectives: Cancer-related fatigue (CRF) is associated with tiredness and sleepiness. It remains unclear, whether such complaints are associated with neurophysiological signs of sleep proneness or a state of neurophysiological hyperarousal in which the patient finds it difficult to relax and to initiate sleep. Therefore the goal of this study is to compare the electroencephalographic (EEG)-vigilance regulation of patients with CRF and healthy controls.
Methods: A 15-min resting EEG with eyes closed was recorded in 22 patients with CRF and 22 matched healthy controls. Consecutive 1-s segments were classified into seven different vigilance stages ranging from high alertness to relaxed wakefulness (stage 0, A1, A2, A3) and further on to drowsiness (B1, B2/3) and sleep onset (stage C).
Results: Results showed that patients with CRF revealed a higher number of vigilance stages A3 (mean 15.26 vs. 6.67%, P = 0.004) dropped significantly earlier to vigilance levels A3 (drop after 130.8 vs. 533.3 s, P = 0.000) and B2/3&C (407.8 vs. 604.1 s, P = 0.035) and showed significantly more transitions between vigilance stages (46.0 vs. 31.1%, P = 0.003) in comparison to healthy controls.
Conclusions: These findings suggest an unstable vigilance regulation in patients with CRF and provide a neurophysiological framework for the reported efficacy of psychostimulants in CRF.