Tinnitus loudness is a subjective measure, and it does not directly reflect either tinnitus severity or the impact on daily life. Nevertheless, loud tinnitus may be the most frequent clinical complaint of tinnitus patients. Factors contributing to the loudness of the phantom sound have rarely been studied. We evaluated both matched and self-rated loudness in a large sample of patients with tinnitus and analyzed the influencing factors among demographic, hearing, and tinnitus characteristics.
Two hundred ninety-nine patients with chronic tinnitus were enrolled. We evaluated the matched loudness, minimal masking level (MML), and visual analog scale (VAS) loudness. Stepwise multiple regression analyses were performed for each loudness measure using independent variables of age, sex, time since tinnitus onset, tinnitus laterality, pure-tone average, tinnitus pitch, tinnitus handicap inventory (THI) score, VAS annoyance, disturbance and daily tinnitus duration, and depression score. We calculated bivariate correlations between each loudness measure and all independent variables.
The psychoacoustic loudness measures (matched loudness and MML) were highly correlated and were affected by the hearing deficit and tinnitus pitch (Pearson r > 0.5 for pure tone averages, and r > 0.3 for tinnitus pitch for both variables, p < 0.05), whereas the subjective measurement (VAS loudness) exhibited little to no correlation with the other two measures and was related to psycho-emotional factors such as the THI score, VAS variables, and depression (Pearson r > 0.6 for VAS annoyance, r > 0.4 for VAS daily duration and disturbance and THI score, r > 0.3 for the depression score, p < 0.05).
The matched tinnitus loudness and MML values were influenced principally by the extent of hearing loss and related factors, suggesting that rehabilitation using hearing aids could help reduce perception of tinnitus loudness. A psycho-emotional approach might more effectively lessen self-perceived loudness.