Acoustic Reflex Thresholds in Tinnitus Patients with Normal Hearing

Abstract

Introduction: Tinnitus is a prevalent auditory phenomenon that can manifest even in individuals with normal hearing acuity. Acoustic reflex threshold (ART) testing provides an objective evaluation of auditory pathway functionality and may aid in detecting auditory anomalies in individuals with tinnitus.Objective: To assess ipsilateral acoustic reflex thresholds in tinnitus patients with normal hearing and compare them with those of healthy controls, as well as to examine their correlation with tinnitus severity, duration, and pattern.Methods: This prospective case-control study comprised 80 participants: 40 individuals with tinnitus (52 ears) and 40 healthy controls (80 ears). All individuals had normal otoscopic results, type A tympanogram, and normal pure-tone audiometry. Ipsilateral auditory reflex thresholds were assessed at frequencies of 500, 1000, 2000, and 4000 Hz, in addition to broadband noise. The severity of tinnitus was evaluated using the Tinnitus Handicap Inventory.Results: ARTs were markedly elevated in tinnitus patients compared to controls across all assessed frequencies and broadband noise (BBN) (p<0.05). No significant differences in ARTs were detected between the slight-to-mild and moderate-to-severe tinnitus groups (p>0.05). Patients with tinnitus of duration greater than 1 year exhibited significantly elevated ARTs compared to those with shorter durations (p < 0.05). Continuous tinnitus was correlated with elevated auditory response thresholds compared to intermittent tinnitus at 1000, 2000, and 4000 Hz and broadband noise (p<0.05).Conclusion: Tinnitus patients with normal hearing demonstrate higher acoustic reflex thresholds, suggesting altered auditory pathway function. The duration and pattern of tinnitus were correlated with alterations in ART, although the severity of tinnitus was not.