Investigation of Hyperacusis in Patients with Tinnitus

Hyperacusis is defined as a decreased tolerance to common everyday sounds. A numer of the sufferers have tinnitus. Therefore, this study aimed to compare the hyperacusis scores between tinnitus sufferers and people without tinnitus.

This case-control study had 80 participants (the case group or hyperacusis-tinnitus sufferers =40 and the control group or normal subjects=40). Data were collected using tympanometry, pure tone audiometry, word-in-noise perception test, loudness discomfortable (LDL) test and the Persian-version of the Khalfa hyperacusis questionnaire (HQ). Data analysis was done using independent samples t-test, Mann-Whitney, Chi-square and Kruskal-Wallis tests. The significance level of less than 0.05 was considered.

In hyperacusis-tinnitus sufferers, the mean scores of hyperacusis (24.17±6.83) were meaningly (p=0.00) more than of normal subjects (8.38±9.16). The causal relations were found between them in terms of hearing loss (P=0.00). The differences among the two groups in terms of hyperacusis scores were significant, in patients over 40 years of age (p=0.01), but not in those under 40 years of age (p=0.06). In hyperacusis-tinnitus sufferers, no causal relationships were found among hyperacusis scores with sex, degree of hearing loss and its type.

Hyperacusis is more common in old patients combined tinnitus and hearing loss. Gender, severity and nature of hearing loss are not related to the grade of hyperacusis. A common mechanism of central auditory processing disorder is related to tinnitus and hyperacusis, which can them to occur concomitantly. The complete and careful evaluation of patients with tinnitus and hyperacusis is essential.