Low-frequency sound exposure causes reversible long-term changes of cochlear transfer characteristics

Drexl, Markus; Otto, Larissa; Wiegrebe, Lutz ; Marquardt, Torsten; Gürkov, Robert und Krause, Eike (2016): Low-frequency sound exposure causes reversible long-term changes of cochlear transfer characteristics. In: Hearing Research, Vol. 332: pp. 87-94

Abstract

Intense, low-frequency sound presented to the mammalian cochlea induces temporary changes of cochlear sensitivity, for which the term 'Bounce' phenomenon has been coined. Typical manifestations are slow oscillations of hearing thresholds or the level of otoacoustic emissions. It has been suggested that these alterations are caused by changes of the mechano-electrical transducer transfer function of outer hair cells (OHCs). Shape estimates of this transfer function can be derived from low-frequency biased distortion product otoacoustic emissions (DPOAE). Here, we tracked the transfer function estimates before and after triggering a cochlear Bounce. Specifically, cubic DPOAEs, modulated by a low-frequency biasing tone, were followed over time before and after induction of the cochlear Bounce. Most subjects showed slow, biphasic changes of the transfer function estimates after low-frequency sound exposure relative to the preceding control period. Our data show that the operating point changes biphasically on the transfer function with an initial shift away from the inflection point followed by a shift towards the inflection point before returning to baseline values. Changes in transfer function and operating point lasted for about 180 s. Our results are consistent with the hypothesis that intense, low-frequency sound disturbs regulatory mechanisms in OHCs. The homeostatic readjustment of these mechanisms after low-frequency offset is reflected in slow oscillations of the estimated transfer functions. (C) 2015 Elsevier B.V. All rights reserved.

• Item Type: Journal article
• Faculties: Biology > Department Biology II > Neurobiology
• Subjects: 600 Technology > 610 Medicine and health
• ISSN: 0378-5955
• Language: English