Influence of aging on medial olivocochlear system function

Abstract

BackgroundThere is still controversy regarding the influence of aging on medial olivocochlear (MOC) system function. The main objective of this study is to measure age-related changes of MOC system function in people with normal hearing thresholds.MethodBilateral assessment of the MOC effect for click-evoked otoacoustic emissions (CEOAEs; at 70±3 dB peak sound pressure level [pSPL], click at 50/second, 260 repeats, 2.5–20 millisecond window) and for distortion product otoacoustic emissions (DPOAEs; with [frequencies] f2/f1=1.22, [levels of primary tones] L1=65 dB SPL and L2=55 dB SPL; DP-grams for 2f1–f2 were collected for the f1 frequencies varying from 977 Hz to 5,164 kHz, with the resolution of four points per octave) was performed in a group of 146 (n=292 ears) healthy, right-handed subjects aged from 10–60 years with a bilateral hearing threshold from 0.25–4.0 kHz, not exceeding 20 dB hearing level; normal tympanograms; and a threshold of the contralateral stapedial reflex for broadband noise (BBN) of 75 dB SPL or higher. The MOC inhibition was assessed on the basis of changes in OAE level during BBN contralateral stimulation at 50 dB sensation level (mean, 65±3 dB SPL).ResultsComparative analysis of the MOC effect for CEOAE and DPOAE showed the weakest effect in the oldest age group (41–60 years) at almost all tested frequencies. Moreover, a weak, albeit significant, positive correlation between the level of OAE and the size of the MOC effect was documented.ConclusionOn the basis of our study, we have found a decrease in the strength of the MOC system with increasing age in normally hearing subjects, as reflected by a decrease of the OAE suppression effects in older individuals and an increase of the number of CEOAE and DPOAE enhancements during contralateral acoustic stimulation in the elderly, especially in the high-frequency range.

Concurrent measures of contralateral suppression of transient-evoked otoacoustic emissions and of auditory steady-state responses

“…Clinical populations, such as hearing-impaired individuals, often experience significant difficulties communicating in background noise. It has been suggested that some hearing-in-noise problems could be due at least in part to compromised MOC function (Keppler et al, 2010;Lisowska et al, 2014). However, little is known about how the MOC system functions in ears with hearing loss, primarily due to methodologic barriers.…”

Langzeit-Entwicklung von akutem Tinnitus

“…aus der psychosozialen Situation der Betroffenen heraus. Studien zeigen Veränderungen otoakustischer Emissionen mit steigendem Lebensalter, welche über eine im efferenten medialen olivocochleären System nachlassende Wirkung acetylcholinerger Hemmung erklärt wird [51,52]. In Tiermodellen wurde gezeigt, dass inhibitorische Mechanismen in den auditorischen Gehirngebieten durch akustische Traumata und mit steigendem Alter geschwächt werden [10,51,53].…”

Heightened visual attention does not affect inner ear function as measured by otoacoustic emissions

“…It might be argued that the effect exists, but that the current procedure is not sensitive enough to detect it. However we reiterate that very strict criteria were used (SNR >12 dB), much higher than in standard measurements (e.g., SNR >3 or >6 dB, Mishra & Lutman, 2013 ; Lisowska et al, 2014 ; Micarelli et al, 2016 ; Killan et al, 2017 ). Another reason for seeing no effect might be because all TEOAE parameters, and especially contralateral suppression effects on TEOAEs, have high variability, even when refitting of the probe is avoided ( Mishra & Lutman, 2013 ; Stuart & Cobb, 2015 ; Jedrzejczak et al, 2016 ).…”