AWARENESS OF PHYSIOLOGICAL RESPONDING UNDER STRESS AND NONSTRESS CONDITIONS IN TEMPOROMANDIBULAR DISORDERS

To test the hypothesis that individuals with temporomandibular disorde rs (TMD) have deficits in proprioceptive awareness, 20 TMD patients we re compared with 20 nonpain individuals matched to the TMD patients on age and gender. Left and right frontalis, masseter, and temporalis we re monitored, as were forearm extensor, heart rare, and skin conductan ce while the participants viewed a nonstressful film segment. Followin g the film segment, participants provided self-reports of these physio logical responses, This sequence was repeated for a second, stressful film segment and for a third, non-stressful film segment. Correlations between physiological activity and self-report were used as measures of proprioceptive awareness. The results indicated that TMD subjects w ere most accurate in their awareness of facial muscle activity during the stress condition and least accurate in the two nonstress periods. Control subjects increased their accuracy of awareness at each time pe riod showing significantly greater accuracy than the TMD group in the last, nonstress period. TMD subjects more accurately perceived activit y of the nonfacial muscle variables in the two nonstress periods than during the stress period These findings may provide a mechanism for un derstanding clinical observations showing that TMD patients with myofa scial pain engage in high levels of parafunctional oral activity witho ut awareness.