# White Matter Microstructural Correlates of Auditory Brainstem Responses in Patients With Charcot‐Marie‐Tooth Disease

## TL;DR

This study explores how white matter changes in the brain of CMT patients relate to auditory nerve function, offering new insights into the disease's impact on the central nervous system.

## Contribution

The study identifies specific white matter regions in CMT patients that correlate with auditory brainstem response changes, suggesting a link between axonal-myelin damage and auditory dysfunction.

## Key findings

- CMT patients showed decreased FA and increased MD, AD, and RD in specific white matter regions compared to controls.
- ABR interpeak latencies correlated with DTI metrics in the inferior longitudinal fasciculus and anterior thalamic radiation.
- Altered white matter microstructure in CMT may impair central auditory processing through axonal degeneration and demyelination.

## Abstract

Some patients with Charcot‐Marie‐Tooth disease (CMT) exhibit prolonged auditory brainstem response (ABR) latencies or abnormal waveforms, suggesting potential damage to the peripheral auditory nerve or central auditory pathways. Diffusion tensor imaging (DTI), a non‐invasive neuroimaging technique, can detect the integrity and functional properties of white matter structures with high sensitivity. However, research on the association between DTI characteristics and ABR changes in patients with CMT remains relatively limited, and whether both modalities reflect synergistic damage to central‐peripheral nerve axons or myelin sheaths remains unclear. In this study, we aimed to analyze cerebral white matter microstructural abnormalities in patients with CMT using DTI and explore their correlation with ABR, thereby exploring the pathophysiological mechanisms of the central auditory pathway in patients with CMT.

This study included 14 patients with CMT and 14 healthy controls. DTI data were acquired using a 3.0T MRI scanner. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated. The latencies and interpeak latencies of the auditory pathway were measured using ABR. DTI metrics were compared between the two groups, and the relationship between DTI parameters and ABR results was analyzed in patients with CMT.

Compared with the healthy controls, patients with CMT exhibited significantly decreased FA values and significantly increased MD, AD, and RD values in brain regions p < 0.05), including the occipital part of the corona radiata, inferior longitudinal fasciculus, anterior thalamic radiation, and inferior fronto‐occipital fasciculus. ABR interpeak latencies correlated positively with FA in the left inferior longitudinal fasciculus and negatively with AD. Three participants did not complete the ABR test. ABR latencies in CMT patients were significantly correlated with AD values in the anterior thalamic radiation and corpus callosum (p < 0.05).

Abnormal central white matter microstructure (axonal degeneration, demyelination) in patients with CMT may lead to auditory pathway dysfunction by impairing neural conduction efficiency. The multimodal correlation analysis of DTI and ABR provides new insights into the mechanism of central nervous system involvement in CMT, suggesting its potential as a clinical biomarker.

We quantitatively analyzed the cerebral white matter microstructure in patients with CMT using DTI. We identified cerebral white matter microstructural abnormalities in CMT patients, including the FMA and ILF. These alterations correlated with ABR interpeak latencies, suggesting impaired central auditory processing due to disrupted axonal‐myelin integrity.