Investigation of the fine-structure hearing threshold in tinnitus patients with normal hearing

Chronic tinnitus can often be temporally associated with a loss of sensorineural hearing. However, tinnitus can also occur in people with normal hearing and thus arise without a traceable disorder in the inner ear. In the present study, we tested whether fine-structure audiometry or high-resolution measurement of otoacoustic emissions can reveal evidence of inner-ear-related disorders that remain undetected by conventional manual tone audiometry.

Methods Study cohort with normal-hearing subjects, tinnitus subjects (N = 15), and control group (N = 14). Study inclusion after performing manual pure tone audiometry with 11 test frequencies at maximum hearing loss 10 dB HL (one exception maximum 15 dB HL tolerated). Békésy gliding frequency audiometry with 794 test frequencies, fine structure DPOAE measurement with 36 test frequencies.

Results Fine structure measurement revealed areas of hearing loss not mapped by manual pure tone audiometry. These "undetected" hearing losses would have resulted in the exclusion of 12 of 29 subjects (41.4%) if the fine structure hearing curve had been used as an inclusion criterion. Comparison of the mean fine-structure hearing curves of both test groups showed a significantly lower hearing loss of about 4 dB in the tinnitus group (p < 0.05) in 3 different test frequency ranges (1.5 kHz, 3 kHz, 7 kHz).

Conclusion The results of this work suggest that in previous studies with normal hearing tinnitus subjects, there may have been an unrecognized hearing loss or subjects with previously above average hearing may have experienced a subtle spontaneous decrease in their hearing as tinnitus pathogenesis.

 

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Conflict of Interest

The author declares that there is no conflict of interest.

Publikationsverlauf

Artikel online veröffentlicht:
24. Mai 2022