EEG-vigilance in patients with tumor-associated fatigue syndrome in comparison to healthy controls

Chronic fatigue syndrome (CSF) is marked by a sustained subjective exhaustion that can not be compensated by sleeping. Often these feelings of drowsiness and depletion occur in association with a malignant tumor. Up to date only little research has been done analyzing possible electroencephalographic (EEG) correlates of the CFS. We postulated the hypothesis that patients suffering from malignant tumor-associated CFS reveal lower EEG-vigilance stages than healthy controls do. For testing this we conducted 15 minutes of resting-EEG recordings in 22 patients suffering from CSF during remission of a malignant tumor and in 22 healthy controls. Consecutive 2-seconds EEG-segments were classified into five distinct EEG-vigilance stages, CFS was assessed using Multiple Fatigue Inventory and depressive comorbidity was conceived by the Hamilton Depression and Anxiety Scale as well as the Beck Depression Inventory. Significantly more vigilance stages A1 and a tendency of decreased vigilance stages B1 were found in patients with CFS in comparison to healthy controls. Patients with CSF revealed increased levels of high vigilance when compared to healthy controls. This is in contrast to the hypothesis of a fast decline in EEG-vigilance in patients with CFS. Despite the subjective feeling of drowsiness, those patients show a decreased rigidity of EEG-vigilance.