Tinnitus, sound intolerance, and mental health: the role of long-term occupational noise exposure.

PURPOSE: Whereas chronic noise exposure (CNE) is a known risk factor for tinnitus, little is known about how a history of CNE impacts tinnitus characteristics and its comorbid symptoms. METHODS: Seventy-five participants with chronic tinnitus (59m/16f, 22-78 years, 48 with sensory-neural hearing loss, and 27 with a normal audiogram) including 43 individuals with (Tin-CNE group) and 32 without (Tin group) a history of long-term occupational noise exposure were studied. Tinnitus characteristics were rated by a visual analog scale, and tinnitus comorbid symptoms were scored using self-assessment questionnaires. RESULTS: The Tin-CNE group showed reduced uncomfortable loudness level (ULL), sound tolerance, and quality of life (QoL), and increased tinnitus loudness, tinnitus handicap, anxiety, depression, insomnia severity, and tinnitus annoyance scores compared to the Tin group. Higher tinnitus loudness and a lower anxiety score were observed in participants with hearing loss relative to those without. Using a stepwise regression model also showed that tinnitus-related characteristics, hyperacusis, and tinnitus comorbid symptoms enhance one another. CONCLUSIONS: The findings were in support of accumulative evidence indicating the adverse auditory and non-auditory effects of CNE, including exacerbated sound intolerance and tinnitus-related psychiatric symptoms. The results also showed that tinnitus alone can affect mental health regardless of hearing loss.