Influence of Clinical, Physical, Psychological and Psychophysical Variables on Treatment Outcomes in Somatic Tinnitus associated to 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 to TMD. METHODS: A secondary analysis of a clinical trial investigating the effectiveness of including cervico-mandibular manual therapy into an exercise combined with education program in 61 subjects with TMD-related tinnitus was performed. Clinical outcomes including tinnitus severity and related-handicap were assessed at 3 and 6 months post-intervention. Patients completed at baseline clinical (severity, handicap, quality of life), physical (range of motion), psychological (depression), and psychophysical (pressure pain thresholds, PPTs) variables which 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 from 13% to 41% of the variance) in both groups. Higher scores of related-handicap at baseline predicted better outcome of tinnitus handicap (45% variance) in the manual therapy with exercise/education group. Lower PPTs over the temporalis muscle at baseline predicted poorer clinical outcomes (from 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, e.g., sex, quality of life, were less influent.