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Diffusion‐Weighted Magnetic Resonance Imaging: A Diagnostic Tool for Auditory (Axonal) Neuropathy

Year: 2025

Type: article

Abstract: BACKGROUND: Axonal neuropathies are disorders that impair neural transmission, leading to substantial sensory deficits. In the auditory system, axonal degeneration can disrupt auditory processing, causing significant hearing difficulties. Understanding the extent of axonal degeneration and its impact on auditory function is crucial for improving diagnosis and management. This study aims to quantify axonal degeneration in the VIIIth nerve using diffusion-weighted MRI and to correlate these findings with auditory function. METHODS: Fifty-two children and adults participated. A total of, 27 with normal hearing, 7 with cochlear hearing loss and 18 with auditory neuropathy (AN). Hearing thresholds and dMRI data was collected for all participants and the VIIIth nerve was evaluated using the fixel-based analysis metric of Apparent Fibre Density (AFD). RESULTS: AFD was significantly lower in participants with AN compared to participants with normal hearing and cochlear hearing loss (p < 0.05). 9/18 participants with AN exhibited AFD values ≥ 2 standard deviations below the normal range. Additionally, AFD was strongly correlated with hearing thresholds in participants with no evidence of cochlear dysfunction (r = -0.776, p < 0.001), suggesting reduced auditory nerve fibre density is associated with impaired sound detection. CONCLUSIONS: dMRI-derived AFD is a sensitive marker for axonal degeneration in the VIIIth nerve. This study provides the first in vivo evidence linking VIIIth nerve microstructure with hearing thresholds, highlighting the potential of dMRI in diagnosing and monitoring AN. The findings suggest that dMRI could be a valuable tool in clinical settings for assessing auditory nerve health and guiding treatment strategies for individuals with AN.

Source: European Journal of Neurology

DOI: 10.1111/ene.70083

Authors: Julien Zanin, Gary Rance

Institution: The University of Melbourne

Language: English

Topic: Hearing, Cochlea, Tinnitus, Genetics

Subfield: Sensory Systems

Field: Neuroscience

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $3,600