Visible and near-infrared spectral changes in the thumb of patients with chronic fatigue syndrome

Abstract

Background Chronic fatigue syndrome (CFS) patients show a persistent fatigue condition with muscle pain and impairment of concentration, memory, and sleep. Presently, the physiological basis of CFS remains unclear. In this study, spectroscopic differences in the thumb were compared between 103 CFS patients and 122 healthy controls to examine possible changes of levels of oxygenated or deoxygenated hemoglobin. Methods Visible and near-infrared (Vis–NIR) spectroscopy was used to examine possible changes in the region of 600–1100 nm. Results Vis–NIR spectra showed sharp peaks at 694, 970 and 1060 nm and broad peaks in the regions of 740–760 and 830–850 nm. As these peaks are possibly related to oxyhemoglobin, cytochrome c oxidase and water, levels of these factors were compared between the two groups. Statistical analysis of the absorbance of Vis–NIR spectra showed a significant decrease in water content, a significant increase in oxyhemoglobin content, and a significant increase in the oxidation of heme a + a 3 and copper in cytochrome c oxidase in CFS patients. Conclusions These changes imply accelerated blood flow and energy metabolism in the thumbs of CFS patients.