Association of Hearing Loss With Anatomical and Functional Connectivity in Patients With Mild Cognitive Impairment

Abstract

ImportanceHearing loss is the most important modifiable risk factor for cognitive impairment; however, the association of hearing loss with anatomical and functional connectivity is not fully understood. This association may be elucidated by evaluating the findings of newer imaging technologies.ObjectivesTo evaluate the association of hearing loss with anatomical and functional connectivity in patients with mild cognitive impairment (MCI) by using multimodal imaging technology.Design, Setting, and ParticipantsThis was a prospective cross-sectional study of patients with MCI under the care of a neurology clinic at the Soonchunhyang University Bucheon Hospital (Republic of Korea) from April to September 2021. Data were analyzed from April 1 to June 30, 2022.Main Outcomes and MeasuresPure tone averages (PTA) and word recognition scores were used to measure hearing acuity. Magnetic resonance imaging (MRI) and positron emission tomography scans of the brain were used to assess functional and anatomical connectivity. Results of diffusion MRI, voxel- and surface-based morphometric imaging, and global brain amyloid standardized uptake ratio were analyzed. Neuroimaging parameters of patients with MCI plus hearing loss were compared with those of patients with MCI and no hearing loss. Correlation analyses among neuroimaging parameters, PTA, and word recognition scores were performed.ResultsOf 48 patients with MCI, 30 (62.5%) had hearing loss (PTA >25 dB) and 18 (37.5%) did not (PTA ≤25 dB). Median (IQR) age was 73.5 (69.0-78.0) years in the group with hearing loss and 75.0 (65.0-78.0) years in the group with normal hearing; there were 20 (66.7%) and 14 (77.8%) women in each group, respectively. The group with MCI plus hearing loss demonstrated decreased functional connectivity between the bilateral insular and anterior divisions of the cingulate cortex, and decreased fractional anisotropy in the bilateral fornix, corpus callosum forceps major and tapetum, left parahippocampal cingulum, and left superior thalamic radiation. Fractional anisotropy in the corpus callosum forceps major and bilateral parahippocampal cingulum negatively correlated with the severity of hearing loss shown by PTA testing. The 2 groups were not significantly different in global β-amyloid uptake, gray matter volume, and cortical thickness.Conclusion and RelevanceThe findings of this prospective cross-sectional study suggest that alterations in the salience network may contribute to the neural basis of cognitive impairment associated with hearing loss in patients who are on the Alzheimer disease continuum.

Comparative Analysis of Intellectual Quotient in Developmental Population with Severe Hearing Loss: Hearing Aids vs. Cochlear Implant Users

“…This study included patients aged between 6.5 and 8 years, who underwent hearing rehabilitation before language development. The IQs identified in the patients after treatment were consistent with previous research looking at the opposite side of the history, deaf people suffer from cognitive deficits in absence of adequate hearing rehabilitation [1][2][3][4].…”

“…The absence of differences in terms of cognitive development may indicate that CI works better than HA, as previously shown in the literature [4,6]; in fact, some of the patients in the HA group had moderate hearing loss (Table 3) at T0, which could have impacted the IQs at T1. Indeed, preservation of the auditory functions has been associated with better functioning of all brain connections [2,8,9], and has been shown that severe and moderate hearing loss affects brain development differently [11,20]. Children with mild-to-severe hearing loss tend to develop the right hemisphere of the brain more than healthy subject to compensate the auditory deficit, allowing them to present cognitive abilities like normal hearing subjects [21].…”

“…Cognitive skills such as language, memory, reasoning, perceptual functioning, and visuomotor functions are essential for proper integration into society, and the loss of a sense such hearing can be a social barrier. The early rehabilitation of hearing loss is essential to avoid difficulties in cognitive development, communication, and social interaction [1][2][3][4].…”

Neurovascular coupling dysfunction associated with cognitive impairment in presbycusis

“…In summary, the primary observation of Papez circuit involvement is reasonable, as patients with presbycusis are more often accompanied by mood disorders, 41 , 42 cognitive deficits and difficulties in managing social relationships, which is consistent with previous neuroimaging findings. 43 , 44 …”