Background and Objectives Sleep is a highly organised biological process that is an important component of functioning and well-being of human. Sleep disorders have been referred as one of the main symptoms of Fibromyalgia. However, after the pain, sleep disorder symptoms is most often referenced by these individuals, including non-restorative sleep, insomnia and poor quality sleep. Recent studies suggest a reciprocal relationship between pain and sleep. Thus, the new diagnostic criteria proposed by American College of Rheumatology (ACR) suggest that sleep should be a central aspect of Fibromyalgia clinical evaluation. The objective of this study is evaluate the psychometric properties of the MOS Sleep Scale in patients with Fibromyalgia.
Materials and Methods The MOS Sleep Scale was sent by mail to 229 individuals with Fibromyalgia, members of National Association Against Fibromyalgia and Chronic Fatigue Syndrome - MYOS, Northern Region. Individuals who responded (sample test-retest), was sent back after 10 days. Subsequently was tested reliability and validity. Internal consistency was assessed using Cronbach's alpha reliability and intraobserver reliability by intraclass correlation coefficient. Construct validity was determined by formulating hypotheses developed based on another measure, FIQ-P.
Results Most subjects were female (94.5%) with a mean age of 52.40 ± 11.05. The Cronbach's alpha showed acceptable values above 0.70 for all domains. They demonstrated good intra-observer reliability with intraclass correlation coefficient of 0.80 and standard error of measurement of 9.10.
Conclusions The results of this study demonstrated good levels of reliability and construct validity of the MOS Sleep Scale, which is an appropriate instrument to evaluate sleep disturbances in individuals with fibromyalgia.