The Effect of Parkinson's Disease on Otoacoustic Emissions and Efferent Suppression of Transient Evoked Otoacoustic Emissions

Abstract

Purpose Several studies have demonstrated increased auditory thresholds in patients with Parkinson's disease (PD) based on subjective tonal audiometry. However, the pathophysiological mechanisms underlying auditory dysfunction in PD remain elusive. The primary aim of this study was to investigate cochlear and olivocochlear function in PD using objective measurements and to assess the effect of dopaminergic medication on auditory function. Method Eighteen patients with PD and 18 gender- and age-matched healthy controls (HCs) were included. Patients with PD participated in medication on and off conditions. Linear mixed models were used to determine the effect of PD on tonal audiometry, transient evoked and distortion product otoacoustic emissions (OAEs), and efferent suppression (ES). Results Tonal audiometry revealed normal auditory thresholds in patients with PD for their age across all frequencies. OAE signal amplitudes demonstrated a significant interaction effect between group (PD vs. HC) and frequency, indicating decreased OAEs at low frequencies and increased OAEs at high frequencies in patients with PD. No significant differences were found between patients with PD and HCs regarding ES. In addition, no significant effect of medication status was found on auditory measurements in patients with PD. Conclusions Altered OAEs support the hypothesis of cochlear alterations in PD. No evidence was found for the involvement of the medial olivocochlear system. Altogether, OAEs may provide an objective early indicator of auditory alterations in PD and should complement subjective tonal audiometry when assessing and monitoring auditory function in PD.

Age-Related Changes in the Cochlea and Vestibule: Shared Patterns and Processes

“…Like Alzheimer's disease, Parkinson's disease and the related Lewy body disease are also associated with cognitive impairment in middle to late life and both peripheral auditory and vestibular impairment (Hardy et al, 2016;Jafari et al, 2020;Johnson et al, 2020). Multiple studies report increased audiometric hearing thresholds (after adjustment for the effect of ARHL) in patients with Parkinson's disease and reduced otoacoustic emission (OAE) amplitudes (reviewed in Jafari et al, 2020;De Groote et al, 2021). Even asymptomatic hearing impairment frequently occurs in early-onset Parkinson's Disease (Shetty et al, 2019).…”

Parkinson's disease affects the neural alpha oscillations associated with speech‐in‐noise processing

“…However, these measures do not capture all aspects of peripheral and central auditory processing. For example, altered otoacoustic emissions have been found in persons with PD in the presence of normal auditory thresholds for their age, indicating a subclinical cochlear dysfunction (De Groote et al, 2021b;De Keyser et al, 2019). Furthermore, the efferent olivocochlear system may be involved in auditory dysfunction in PD (Gökay et al, 2021), which has been implicated in speechin-noise processing as well (Giraud et al, 1997;Mertes et al, 2019).…”

“…Furthermore, the efferent olivocochlear system may be involved in auditory dysfunction in PD (Gökay et al, 2021), which has been implicated in speechin-noise processing as well (Giraud et al, 1997;Mertes et al, 2019). Note however, that non-differences regarding the efferent suppression of otoacoustic emissions have also been observed between persons with PD and HCs (De Groote et al, 2021b). At higher levels, auditory processing may be compromised by brainstem (Venhovens et al, 2016), subcortical (Nojszewska et al, 2009), and cortical (Tsuchiya et al, 2000) alterations.…”