Peripheral and central auditory dysfunction in tinnitus with clinically normal hearing.

Area of Science:

• Audiology
• Neuroscience
• Otolaryngology

Background:

• Tinnitus, perceived ringing without external sound, occurs despite normal hearing thresholds, indicating potential undetected auditory dysfunction.
• Ultra-high frequency (UHF) hearing loss and cochlear synaptopathy are proposed mechanisms disrupting auditory processing.
• Current tinnitus assessment often lacks integrated peripheral and central auditory processing evaluations.

Purpose of the Study:

• To systematically integrate central auditory processing measures (TFS-AF, AMD) with peripheral assessment (UHF audiometry).
• To characterize peripheral and central auditory deficits in tinnitus patients with normal hearing.
• To evaluate the diagnostic accuracy of UHF audiometry and central measures in this population.

Main Methods:

• A case-control study involving 28 tinnitus patients and 28 age/gender-matched controls.
• Assessment included UHF audiometry (9-20 kHz), Temporal Function Scale - Amplitude Modulation Following (TFS-AF), and Auditory Multidimensional Scaling (AMD) tasks.
• Tinnitus severity was measured using the Tinnitus Functional Index (TFI). Diagnostic accuracy was analyzed using Receiver Operating Characteristic (ROC) curves, regression, and Bland-Altman analyses.

Main Results:

• Tinnitus patients showed significant differences across all measures (TFS-AF, AMD, UHF) compared to controls, indicating disrupted temporal processing.
• Bland-Altman plots revealed systematic biases: TFS-AF values were higher than UHF thresholds, and AMD scores were lower.
• UHF audiometry achieved superior diagnostic accuracy (96.43%) in identifying tinnitus in individuals with normal hearing.

Conclusions:

• UHF audiometry demonstrates high sensitivity and diagnostic utility for detecting tinnitus in individuals with normal hearing.
• Systematic biases between peripheral (UHF) and central (TFS-AF, AMD) measures suggest independent deficits.
• Integrated assessment of peripheral and central auditory functions is crucial for a comprehensive understanding of tinnitus in normal-hearing individuals.