Sleep and musculoskeletal pain.

Chronic musculoskeletal pain and fatigue of "fibrositis syndrome" are associated with a physiologic arousal disorder within sleep, the alpha (7.5 to 11 Hz) electroencephalographic, non-rapid-eye-movement sleep anomaly. In this nonrestorative sleep disorder, pain and mood symptoms may be mediated by psychologic distress (e.g., following a nonphysically injurious industrial or automobile accident), noxious environmental stimuli (e.g., noise), physiologic disturbance (e.g., sleep-related myoclonus, painful inflamed joints, i.e., rheumatoid arthritis), and altered central nervous system metabolism (e.g., disordered brain serotoninergic functions). Because such heterogeneous agents influence this hitherto poorly understood nonarticular rheumatic syndrome, the descriptive term "rheumatic pain modulation disorder" is suggested.