A review and clinical perspective on the use of EMG and thermal biofeedback for chronic headaches.

A comprehensive survey of EMG and thermal biofeedback for chronic muscle contraction and migraine headaches is presented. The studies done to date suggest a high degree of short-term efficacy of biofeedback, which has been maintained on long-term follow-ups. While comparisons of biofeedback with relaxation generally have shown approximately equivalent effectiveness, the two forms of therapy may be differentially effective with different subjects. Attempts to correlate EMG and/or thermal parameters with headache parameters generally have failed to produce significant results, particularly in more recent and better-controlled studies; however, numerous technical and procedural difficulties have obscured meaningful interpretation of physiological data. Results with pseudofeedback do suggest a likely specific contribution of frontalis EMG to muscle contraction headaches, at least for some subjects. Comparable evidence for a specific contribution of thermal parameters to migraines is almost totally lacking. Clinical outcome research suggests that biofeedback in general may be more effective in younger anxious subjects who show no chronic habituation to drugs, and that there is little apparent benefit from repeating biofeedback for more than about 12 sessions maximum. Three broad areas for subsequent research are suggested: longitudinal study of EMG and thermal parameters in a naturalistic setting, specification of processes critically involved in biofeedback, and clinically relevant comparative outcome research with biofeedback and alternative therapies.