Longitudinal change in chronic fatigue syndrome: what home-based assessments reveal.

The purpose of this 2-year prospective study was to compare standard self-report and ecologically-based outcome measures in patients with chronic fatigue syndrome (CFS). Standard measures assessed physical function, fatigue impact, psychological variables, and global impression of change ratings. Ecological measures included actigraphy, a structured activity record, and an electronic fatigue/energy diary. Results for this high functioning sample (N = 75) revealed that self-report global improvement was significantly associated with lower momentary fatigue and fatigue impact, and a higher frequency of standing up (at home), but not with actigraphy or psychological variables. However, actigraphy change was significantly correlated with change in self-report physical function. At follow-up, only a small minority (<20%) scored in the healthy adult range for fatigue impact and physical function. The findings suggest that home-based measures of symptom severity and physical functioning may provide evidence of change (or lack of change) that is important for interpreting standard self-report outcomes in CFS.