The specificity of response to experimental stress in patients with myofascial pain dysfunction syndrome.

Comparison of autonomic and muscular response to experimentally induced stress in normal individuals and patients with myofascial pain dysfunction (MPD) syndrome revealed greater masseter and frontalis activity in the patient group, higher gastrocnemius activity in control subjects, and no significant difference in skin conductance and heart rate. This specificity of response to stress supports the psychophysiologic theory of MPD syndrome.