Influence of Clinical, Physical, Psychological, and Psychophysical Variables on Treatment Outcomes in Somatic Tinnitus Associated With Temporomandibular Pain: Evidence From a Randomized Clinical Trial

Objective To assess the influence of clinical, psychological, and psychophysical variables on treatment outcomes after application of exercise combined with education with/without manual therapy in people with tinnitus associated with temporomandibular disorder (TMD). Methods A secondary analysis of a clinical trial was performed investigating the effectiveness of including cervico-mandibular manual therapy into an exercise combined with education program in 61 subjects with TMD-related tinnitus. Clinical outcomes including tinnitus severity and tinnitus-related handicap were assessed at 3 and 6 months post-intervention. Patients were assessed at baseline for clinical (tinnitus severity, tinnitus-related handicap, quality of life), physical (range of motion), psychological (depression), and psychophysical (pressure pain thresholds [PPTs]) variables that were included as predictors. Results The regression models indicated that higher scores of tinnitus severity at baseline predicted better outcomes 3 and 6 months post-intervention (explaining 13% to 41% of the variance) in both groups. Higher scores of tinnitus-related handicap at baseline predicted better outcome of tinnitus-related handicap (45% variance) in the manual therapy with exercise/education group. Lower PPTs over the temporalis muscle at baseline predicted poorer clinical outcomes (10.5% to 41% of the variance) in both groups. Other predictors were sex and quality of life (6.7% variance) in the manual therapy group and PPTs over the masseter muscle (5.8% variance) in the exercise/education group. Conclusion This study found that baseline tinnitus severity and localized PPT over the temporalis muscle were predictive of clinical outcomes in individuals with TMD-related tinnitus following physical therapy. Other predictors (eg, sex, quality of life) were less influential.