Reduced resting state functional connectivity with increasing age-related hearing loss and McGurk susceptibility

Abstract

Age-related hearing loss has been related to a compensatory increase in audio-visual integration and neural reorganization including alterations in functional resting state connectivity. How these two changes are linked in elderly listeners is unclear. The current study explored modulatory effects of hearing thresholds and audio-visual integration on resting state functional connectivity. We analysed a large set of resting state data of 65 elderly participants with a widely varying degree of untreated hearing loss. Audio-visual integration, as gauged with the McGurk effect, increased with progressing hearing thresholds. On the neural level, McGurk illusions were negatively related to functional coupling between motor and auditory regions. Similarly, connectivity of the dorsal attention network to sensorimotor and primary motor cortices was reduced with increasing hearing loss. The same effect was obtained for connectivity between the salience network and visual cortex. Our findings suggest that with progressing untreated age-related hearing loss, functional coupling at rest declines, affecting connectivity of brain networks and areas associated with attentional, visual, sensorimotor and motor processes. Especially connectivity reductions between auditory and motor areas were related to stronger audio-visual integration found with increasing hearing loss.

Treatment of Age-Related Hearing Loss Alters Audiovisual Integration and Resting-State Functional Connectivity: A Randomized Controlled Pilot Trial

“…Increased task-modulated functional connectivity between auditory and visual cortex -when comparing incongruent (McGurk) with congruent audiovisual stimuli -was found in hard-of-hearing compared to normal-hearing participants (Rosemann et al, 2020). Moreover, increased McGurk illusions were correlated with decreased resting state functional connectivity between auditory and motor regions in mild to severe hard-of-hearing individuals (Schulte et al, 2020). Thus, previous research provided evidence for changed audiovisual integration abilities in age-related hearing loss, and functional connectivity alterations in the auditory cortex associated with the McGurk illusion.…”

“…We further used the M1 lip area as a ROI because its neural activity was shown to be related to the McGurk illusion in healthy volunteers (Murakami et al, 2018). Further, studies in age-related hearing loss demonstrated increased neural activity in motor cortex but decreased coupling between auditory and motor regions with increased McGurk illusion responses (Rosemann et al, 2020;Schulte et al, 2020). The ROI in the left and right fusiform gyrus was provided by the atlas implemented in CONN.…”

“…Moreover, we hypothesized a decrease in functional coupling of the auditory cortex to visual areas after hearing aid fitting (Chen et al, 2017;Kral et al, 2016;Puschmann and Thiel, 2017;Shiell et al, 2015). We further expected changes in McGurk illusion perception to be related to changes in functional connectivity between auditory cortex and visual as well as motor brain regions (Rosemann et al, 2020;Schulte et al, 2020).…”

Age‐related hearing loss and cognitive decline: MRI and cellular evidence

“…106 This finding is consistent with past findings that indicate increased frontal recruitment in hearing-impaired individuals as a compensatory mechanism to control for reduced auditory inputs. 107 Studies also demonstrate decreased brain functional connectivity between the dorsal attentional network (DAN) and sensorimotor and motor regions, 108,109 as well as between the SN and the visual cortex in ARHL, 109 which can affect attentional, visual, sensorimotor, and motor processes.…”

Screening Tools and Assessment Methods of Cognitive Decline Associated With Age-Related Hearing Loss: A Review

“…In addition to MRI studies on the local brain regions of patients with ARHL, the whole-brain functional network’s research deserves further discussion. An MRI study on the functional connectivity of the resting state of 65 patients with ARHL found that a higher degree of hearing loss was significantly associated with decreased resting-state functional coupling, and the connectivity of the dorsal attention network gradually decreased with an increase in the hearing loss degree (Schulte et al, 2020 ). The connectivity of the dorsal attention network increases when performing tasks requiring attention and responding to stimuli (Corbetta and Shulman, 2002 ).…”