Reduced grey- and white matter volumes due to unilateral hearing loss following treatment for vestibular schwannoma

Abstract

Objective Previous studies of the consequences of unilateral hearing loss (UHL) on the functional-structural organization of the brain has included subjects with various degrees of UHL. We suggest that the consequences of a total loss of hearing in one ear might differ from those seen in subjects with residual hearing in the affected ear. Thus, the main aim of the present study was to compare the structural properties of auditory and non-auditory brain regions in persons with complete UHL to those of normal hearing controls. We hypothesize that the consequences of complete UHL following treatment for vestibular schwannoma will differ between ipsi- and contralateral structures, as well as between right- and left side deafness. Design A 3T Siemens Prisma MR-scanner was used. Anatomical images were acquired using a high-resolution T1-weighted sequence. Grey- and white matter volumes were assessed using voxel-based morphometry. Study sample Twenty-two patients with left- or right-side unilateral hearing loss. Fifty normal hearing controls. Results Reductions in grey- and white matter volumes were seen in cortical and sub-cortical regions, mainly in the right hemisphere including the auditory cortex, lingual gyrus, cuneus, middle temporal gyrus, occipital fusiform gyrus, middle cingulate gyrus and the superior temporal gyrus. Patients displayed reduced grey- and white matter volumes in cerebellar exterior structures ipsilateral to the tumor side. Conclusion When compared to controls, right side hearing loss yields more widespread reduction of grey matter volume than left side hearing loss. The findings of reduced grey- and white matter volumes in auditory and non-auditory brain regions could be related to problems with speech perception in adverse listening conditions, increased listening effort and reduced quality of life reported by persons with unilateral hearing loss despite normal hearing in the unaffected ear.

Asymmetry in Cortical Thickness of the Heschl’s Gyrus in Unilateral Ear Canal Atresia

“…The previously reported effect on morphometry in unilateral sensorineural hearing loss (19,(21)(22)(23)33) with decreased volumes of the HG was not found in our group of UCA. Neuschwander et al (18) found that higher hearing thresholds in sensorineural bilateral hearing loss were associated with a thinner cortex of the left HG.…”

“…Giroud et al (20) reported a thicker cortex of the right HG in subjects with better speech perception. In acquired unilateral sensorineural hearing loss, a bilateral decrease in volume of the HG has been identified (21)(22)(23), although tinnitus was primarily studied by Schneider et al To the best of our knowledge, the morphology of gray matter in the HG has not been previously reported in cases of unilateral conductive hearing impairment or congenital unilateral hearing loss.…”

Proficiency in Using Level Cue for Sound Localization Is Related to the Auditory Cortical Structure in Patients With Single-Sided Deafness

“…Ear-specific neuroplasticity in patients with asymmetric hearing has been reported, yet the findings are controversial. Recent neuroimaging studies have shown a clear impact of the deafness side, with a greater degree of neural plasticity for right-sided hearing loss ( Cañete et al, 2019 ; Heggdal et al, 2020 ; Han et al, 2021 ). On the other hand, others reported more extensive neurofunctional reorganization in individuals with left-sided hearing loss ( Khosla et al, 2003 ; Hanss et al, 2009 ; Zhang et al, 2016 ).…”

“…Meanwhile, neuroanatomical characteristics of the auditory cortex, such as the change of gray matter volume (GM volume), have shown to be associated with certain types of hearing loss ( Cardin, 2016 ). For example, structural changes in the gray matter in the auditory cortex have been found for patients with mild-to-moderate hearing loss ( Husain et al, 2011 ), high-frequency hearing loss ( Eckert et al, 2012 , 2019 ), and unilateral hearing loss ( Yang et al, 2014 ; Heggdal et al, 2020 ). Yet, the evidence for the structural changes relating to auditory performance in sound localization is limited.…”

Altered static and dynamic intrinsic brain activity in unilateral sudden sensorineural hearing loss

“…The fusiform gyrus is known to be involved in high-order visual information processing, including face recognition and object perception ( Weiner and Zilles, 2016 ; Palejwala et al, 2020 ). It is reported that unilateral hearing loss showed reduced grey matter volumes in fusiform gyrus ( Heggdal et al, 2020 ). Indeed, alterations in the brain activity of the fusiform gyrus have been reported in various neurological conditions, including amyotrophic lateral sclerosis ( Luo et al, 2012 ), Parkinson’s disease ( Pan et al, 2017 ), obsessive–compulsive personality disorder ( Lei et al, 2020 ) and social anxiety disorder ( Qiu et al, 2015 ).…”