Standard and Extend High-Frequency Audiometry in Sudden Sensorioneural Hearing Loss

Introduction: According to the World Health Organization (WHO), unidentified and consequently untreated hearing loss (HL) has an impact on people’s physical and mental health. Sudden sensorineural hearing loss (SSNHL) is a known cause of ongoing tinnitus and HL, but audiometric measurements are usually only made between 250-8,000 Hz. Higher frequency HL (9,000-16,000 Hz) can contribute to both subjective HL and bothersome tinnitus.

Objective: To analyze the results of hearing assessment in standard and in Extended High Frequency (EHF) audiometry and determine if it impacts on the tinnitus and mental health of patients with unilateral SSNHL.

Methods: Prospective cohort study in outpatients with unilateral SSNHL in a tertiary teaching hospital between 2021 and 2022. Patients underwent the following procedures: Pure-tone audiometry tests performed at frequencies from 250-16,000Hz, acuphenometry examining pitch and loudness, completion of Tinnitus Handicap Inventory (THI), Analog and Visual Scale (AVS) for bothersome tinnitus, and the Hospital Anxiety and Depression Scale (HADS).

Results: In this study, 36 patients complaining of sudden hearing loss (SHL) were referred for hearing assessment after consultation with an otolaryngology, however only 18 patients met the inclusion criteria. After onset of treatment, there was a significant improvement (p < 0.05) in the thresholds for both standard and EHF audiometry at 15 days and this hearing improvement persisted at 30 days' follow up. The same was seen with speech recognition threshold (SRT) and word recognition scores (WRS). Regarding sudden tinnitus, there was a significant improvement (p < 0.05) in loudness, the degree of annoyance measured by VAS and THI, as well as significant improvement (p < 0.05) in mental health by the HADS. However, patients whose EHF thresholds did not recover experienced worse tinnitus and anxiety outcomes (p < .05).

Conclusions: Despite improvement in pure-tone thresholds in standard audiometry, there is a subset of patients with SSNHL, who do not experience hearing recovery in EHF, and this is associated with permanence of tinnitus and anxiety.