Many individuals with
tinnitus report experiencing
hyperacusis (enhanced sensitivity to sounds). However, estimates of the association between
hyperacusis and
tinnitus is lacking. Here, we investigate this relationship in a Swedish study. A total of 3645 participants (1984 with
tinnitus and 1661 without
tinnitus) were enrolled via LifeGene, a study from the general Swedish population, aged 18-90 years, and provided information on socio-demographic characteristics, as well as presence of
hyperacusis and its severity.
Tinnitus presence and severity were self-reported or assessed using the
Tinnitus Handicap Inventory (THI). Phenotypes of
tinnitus with (n = 1388) or without (n = 1044)
hyperacusis were also compared. Of 1661 participants without
tinnitus, 1098 (66.1%) were women and 563 were men (33.9%), and the mean (SD) age was 45.1 (12.9). Of 1984 participants with
tinnitus, 1034 (52.1%) were women and 950 (47.9%) were men, and the mean (SD) age was 47.7 (14.0) years.
Hyperacusis was associated with any
tinnitus [Odds ratio (OR) 3.51, 95% confidence interval (CI) 2.99-4.13], self-reported severe
tinnitus (OR 7.43, 95% CI 5.06-10.9), and THI ≥ 58 (OR 12.1, 95% CI 7.06-20.6). The association with THI ≥ 58 was greater with increasing severity of
hyperacusis, the
ORs being 8.15 (95% CI 4.68-14.2) for moderate and 77.4 (95% CI 35.0-171.3) for severe
hyperacusis. No difference between sexes was observed in the association between
hyperacusis and
tinnitus. The occurrence of
hyperacusis in severe
tinnitus is as high as 80%, showing a very tight relationship. Discriminating the pathophysiological mechanisms between the two conditions in cases of severe
tinnitus will be challenging, and optimized study designs are necessary to better understand the mechanisms behind the strong relationship between
hyperacusis and
tinnitus.