Unstable EEG-vigilance in patients with cancer-related fatigue (CRF) in comparison to healthy controls

Abstract

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.

Key words::

• Neuropsychiatry
• biological psychiatry
• cancer-related fatigue
• EEG-vigilance
• depression

Acknowledgements

We would like to thank Prof. Dr. Schwarz, who was engaged in the enrollment of the study. Prof. Schwarz died in 2009.

Statement of Interest

The research group received fees according to the German medical fee schedule for recording of clinical EEG for the CRF study population from Medice. Ulrich Hegerl has been participating in advisory boards of Lilly, Wyeth, Lundbeck and Sanofi-Aventis and received honoraria from Cephalon.