PSYCHOLOGICAL AND PHYSIOLOGICAL-PARAMETERS OF MASTICATORY MUSCLE PAIN

The objective of this research was to identify the psychological and p hysiological variables that differentiate persons reporting masticator y muscle pain (MMP) from normal controls (NC). This study examined the characteristics of 35 MMP patients in comparison to 35 age-, sex-, an d weight-matched NCs. All subjects completed a series of standardized questionnaires prior to undergoing a laboratory evaluation consisting of a psychosocial stressor and pressure pain stimulation at multiple b ody sites. During the evaluation, subjects' emotional and physiologica l responses (heart rate, blood pressure, respiration, skin temperature , and muscle activity) were monitored. Results indicated that persons with MMP reported greater fatigue, disturbed sleep, depression, anxiet y, menstrual symptoms, and less self-deception (P's < 0.05) than match ed controls. At rest, MMPs had lower end tidal carbon dioxide levels ( P < 0.04) and lower diastolic blood pressures than the NCs (P < 0.02). During laboratory challenge, both groups responded to the standard st ressor with significant physiological activity and emotional respondin g consistent with an acute stress response (P < 0.01), but there were no differences between the MMPs and NCs. Muscle pain patients reported lower pressure pain thresholds than did NCs at the right/left massete r and right temporalis sites (P's < 0.05); there were no differences i n pressure pain thresholds between MMPs and NCs for the left temporali s (P < 0.07) and right/left middle finger sites (P's > 0.93). These re sults are discussed in terms of the psychological and physiological pr ocesses that may account for the development of muscle pain in the mas ticatory system. (C) 1998 International Association for the Study of P ain. Published by Elsevier Science B.V.