The association between subcortical and cortical fMRI and lifetime noise exposure in listeners with normal hearing thresholds

Abstract

In animal models, exposure to high noise levels can cause permanent damage to hair-cell synapses (cochlear synaptopathy) for high-threshold auditory nerve fibers without affecting sensitivity to quiet sounds. This has been confirmed in several mammalian species, but the hypothesis that lifetime noise exposure affects auditory function in humans with normal audiometric thresholds remains unconfirmed and current evidence from human electrophysiology is contradictory. Here we report the auditory brainstem response (ABR), and both transient (stimulus onset and offset) and sustained functional magnetic resonance imaging (fMRI) responses throughout the human central auditory pathway across lifetime noise exposure. Healthy young individuals aged 25–40 years were recruited into high (n = 32) and low (n = 30) lifetime noise exposure groups, stratified for age, and balanced for audiometric threshold up to 16 kHz fMRI demonstrated robust broadband noise-related activity throughout the auditory pathway (cochlear nucleus, superior olivary complex, nucleus of the lateral lemniscus, inferior colliculus, medial geniculate body and auditory cortex). fMRI responses in the auditory pathway to broadband noise onset were significantly enhanced in the high noise exposure group relative to the low exposure group, differences in sustained fMRI responses did not reach significance, and no significant group differences were found in the click-evoked ABR. Exploratory analyses found no significant relationships between the neural responses and self-reported tinnitus or reduced sound-level tolerance (symptoms associated with synaptopathy). In summary, although a small effect, these fMRI results suggest that lifetime noise exposure may be associated with central hyperactivity in young adults with normal hearing thresholds.

Characteristic and Sex Differences in Auditory Function and Cochlear Pathophysiology in a Noise-exposed Cohort: A Cross-sectional Study

“…Other studies have demonstrated that noise exposure also has a negative effect on the central auditory pathway. For example, Dewey et al reported that fMRI responses throughout the auditory system were greater in individuals with higher lifetime noise exposure levels than in controls with low lifetime noise exposure levels [37]. In summary, the decreased SIN scores in men in the HHL risk group in our study could result from other dysfunctions of the cochlear or central auditory system.…”

“…Prior studies have demonstrated that noise exposure also has a negative effect on the central auditory pathway. For example, Dewey et al reported that fMRI responses throughout the auditory system were greater in individuals with higher lifetime noise exposure levels than in controls with low lifetime noise exposure levels (Dewey et al 2020).…”

Comparison of continuous sampling with active noise cancelation and sparse sampling for cortical and subcortical auditory functional MRI

“…F I G U R E 2 Region-of-interest definition using an entirely independent data set of 62 participants. 17 The ROIs are shown in the cochlear nucleus (CN), superior olivary complex (SOC), NLL, inferior colliculus (IC), medial geniculate body (MGB) and AC, and overlaid on the grouplevel mean MPRAGE image ("y" denotes the Montreal Neurological Institute (MNI) slice coordinates). The table shows the number of voxels (1.5-mm isotropic) in each ROI by hemisphere 2.2.4 | Region of interest definition The use of anatomical landmarks or manual segmentation is challenging to define auditory brainstem and midbrain ROIs.…”

“…16 Determining the most favorable acquisition method for the assessment of both transient and steady-state auditory responses is paramount for studies requiring sensitivity to both cortical and subcortical activity, such as in the assessment of the effect of noise exposure on the entire ascending auditory pathway. 17 An alternative approach to reduce the impact of background scanner acoustic noise is to apply active noise cancelation (ANC). This approach is based on the principle that an additional carefully tailored acoustic signal can interfere destructively with the scanner acoustic noise, to substantially reduce the overall acoustic energy at a participant's eardrum.…”

Phrases in Noise Test (PINT) Brasil: interpretação dos valores de normalidade

“…No que se refere a sinaptopatia coclear, também conhecida como hidden hearing loss (perda auditiva oculta), Dewey et al (2020) referem que a hipótese de que a exposição ao ruído durante toda a vida afete a função auditiva em humanos com limiares audiométricos normais ainda não foi confirmada.…”