A Controlled Study of Biopsychosocial Differences Observed in Masticatory Myalgia With and Without Pain Referral

To assess differences in biopsychosocial factors between participants with masticatory myofascial pain with referral (MFPwR), with myalgia without referral (Mw/oR), and community controls without TMDs.

Study participants were diagnosed with MFPwR (n = 196), Mw/oR (n = 299), or as a non-TMD community control (n = 87) by two calibrated examiners at each of three study sites. Pain chronicity, pain on palpation of masticatory muscle sites, and pressure pain thresholds (PPT) at 12 masticatory muscle, 2 trigeminal, and 2 nontrigeminal control sites were recorded. Psychosocial factors assessed included anxiety, depression, and nonspecific physical symptoms (Symptom Checklist-90 Revised); stress (Perceived Stress Scale); and health-related quality of life (Short Form Health Survey). Comparisons among the three groups were adjusted for age, sex, race, education, and income using multivariable linear regression. The significance threshold was set at P = .017 (.05 / 3) for subsequent pairwise comparisons.

Compared to the Mw/oR group, the MFPwR group had significantly greater pain chronicity, number of painful muscle sites, anxiety, depression, nonspecific physical symptoms, and impaired physical health (P < .017). The MFPwR group also had significantly lower PPTs for masticatory sites (P < .017). Both muscle pain groups differed significantly from the non-TMD community control group for all outcome measures (P < .017).

These findings support the clinical utility of separating MFPwR from Mw/oR. Patients with MFPwR are more complex from a biopsychosocial perspective than Mw/oR patients, which likely affects prognosis and supports consideration of these factors in case management.