Development and validation of a new fatigue scale for fatigued subjects with and without chronic fatigue syndrome

Abstract

The objective of our study was to develop a new fatigue scale for the assessment of patients with chronic fatigue syndrome (CFS) as well as people who feel they are chronically fatigued but do not meet the diagnostic criteria for CFS. A new fatigue scale was developed by one psychiatrist and two physicians who specialize in CFS. This scale consists of various psychosomatic symptoms, psychiatric symptoms, and diagnostic criteria for CFS. It was completed by 325 patients with CFS, 311 fatigue patients who did not fulfill the diagnostic criteria for CFS, 92 healthy workers, and 80 university students. The Chalder fatigue scale, the profile of mood states (POMS), the performance status (PS), which is included in the Japanese diagnostic criteria for CFS, and the visual analogue scale (VAS) for fatigue were also assessed with the agreement of patients who consulted our center from December 2004 to April 2006. Seventy-two university students also completed the questionnaire, including this new scale, the Chalder fatigue scale, and other lifestyle factors, and we reconfirmed the effectiveness of the new scale among fatigue patients with and without CFS and normal controls. There was a high degree of internal consistency in the results, and principal components analysis supported the notion of an 8-factor solution (42 items covering fatigue, anxiety and depression, loss of attention and memory, pain, overwork, autonomic imbalance, sleep problems, and infection). Only anxiety and depression, pain, and infection factors were able to distinguish CFS from not CFS. The sensitivity and specificity of CFS were 67.7 and 64.4, respectively, using a cut-off score of 25 points for this subscore. We concluded that the new fatigue scale used in this study was useful for differentiating CFS patients from not CFS patients and fatigued people from a healthy sample. © 2008 Springer Japan.