Amplitude-modulation detection by recreational-noise-exposed humans with near-normal hearing thresholds and its medium-term progression

Michael A Stone,Brian C.J Moore

doi:10.1016/j.heares.2014.09.005

Michael A Stone, Brian C.J Moore

Open Access

https://doi.org/10.1016/j.heares.2014.09.005

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Abstract

Noise exposure can affect the functioning of cochlear inner and outer hair cells (IHC/OHC), leading to multiple perceptual changes. This work explored possible changes in detection of amplitude modulation (AM) at three Sensation Levels (SL) for carrier frequencies of 3, 4 and 6 kHz. There were two groups of participants, aged 19 to 24 (Young) and 26 to 35 (Older) years. All had near-normal audiometric thresholds. Participants self-assessed exposure to high-level noise in recreational settings. Each group was sub-grouped into low-noise (LN) or high-noise (HN) exposure. AM detection thresholds were worse for the HN than for the LN sub-group at the lowest SL, for the males only of the Young group and for both genders for the Older group, despite no significant difference in absolute threshold at 3 and 4 kHz between sub-groups. AM detection at the lowest SL, at both 3 and 4 kHz, generally improved with increasing age and increasing absolute threshold, consistent with a recruitment-like process. However, poorer AM detection was correlated with increasing exposure at 3 kHz in the Older group. It is suggested that high-level noise exposure produces both IHC- and OHC-related damage, the balance between the two varying across frequency. However, the use of AM detection offers poor sensitivity as a measure of the effects.

Highlights

Noise-induced hearing damage in humans is associated with an increase in absolute threshold in the frequency range 3e6 kHz, which can later spread to between 2 and 8 kHz (Smoorenburg, 1990)
The histogram for the 32 participants is shown in the upper panel of Fig. 1, where the low-noise (LN) sub-group is indicated by dark gray shading and the high-noise (HN) sub-group by light gray shading
distortion-product otoacoustic emission (DPOAE) and amplitude modulation (AM)-detection thresholds were measured for Young and Older participants with variable degrees of exposure to high-noise events, using test frequencies at which effects of noise exposure are typically first observed

Summary

Introduction

Noise-induced hearing damage in humans is associated with an increase in absolute threshold in the frequency range 3e6 kHz, which can later spread to between 2 and 8 kHz (Smoorenburg, 1990). The audiogram is recognized as being an insensitive measure for quantifying hearing damage, since there may be changes in hearing even when audiometric thresholds are within the “normal” range. Such changes include tinnitus (Davis et al, 1950; Moore, 2012), broadening of the auditory filters (West and Evans, 1990), and reduced otoacoustic emissions (Attias et al, 1998; Hall and Lutman, 1999; Lucertini et al, 2002). The present paper describes a study using a perceptual measure, namely the detection of amplitude modulation (AM) applied to a low-level sinusoidal carrier, which might be useful in early identification of one manifestation of noise-induced hearing damage

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