Exploring Differences in Speech Processing Among Older Hearing-Impaired Listeners With or Without Hearing Aid Experience: Eye-Tracking and fMRI Measurements.

Julia Habicht,Tobias Neher,Oliver Behler,Birger Kollmeier

doi:10.3389/fnins.2019.00420

Julia Habicht, Tobias Neher + Show 2 more

Open Access

https://doi.org/10.3389/fnins.2019.00420

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Abstract

Recently, evidence has been accumulating that untreated hearing loss can lead to neurophysiological changes that affect speech processing abilities in noise. To shed more light on how aiding may impact these effects, this study explored the influence of hearing aid (HA) experience on the cognitive processes underlying speech comprehension. Eye-tracking and functional magnetic resonance imaging (fMRI) measurements were carried out with acoustic sentence-in-noise (SiN) stimuli complemented by pairs of pictures that either correctly (target picture) or incorrectly (competitor picture) depicted the sentence meanings. For the eye-tracking measurements, the time taken by the participants to start fixating the target picture (the ‘processing time’) was measured. For the fMRI measurements, brain activation inferred from blood-oxygen-level dependent responses following sentence comprehension was measured. A noise-only condition was also included. Groups of older hearing-impaired individuals matched in terms of age, hearing loss, and working memory capacity with (eHA; N = 13) or without (iHA; N = 14) HA experience participated. All acoustic stimuli were presented via earphones with individual linear amplification to ensure audibility. Consistent with previous findings, the iHA group had significantly longer (poorer) processing times than the eHA group, despite no differences in speech recognition performance. Concerning the fMRI measurements, there were indications of less brain activation in some right frontal areas for SiN relative to noise-only stimuli in the eHA group compared to the iHA group. Together, these results suggest that HA experience leads to faster speech-in-noise processing, possibly related to less recruitment of brain regions outside the core sentence-comprehension network. Follow-up research is needed to substantiate the findings related to changes in cortical speech processing with HA use.

Highlights

Age-related hearing loss is a common chronic health condition that often remains untreated
The findings summarized above are consistent with the idea that both age and hearing loss lead to the recruitment of cortical areas outside the core sentence-comprehension network, possibly as a result of compensatory mechanisms for achieving speech comprehension
We used a cross-sectional design to explore the influence of hearing aid (HA) experience on cognitive processes related to sentence comprehension in noise

Summary

Introduction

Age-related hearing loss is a common chronic health condition that often remains untreated. Evidence has been accumulating that untreated hearing loss can lead to declines in brain volume and compensatory changes in cortical resource allocation with important consequences for communication abilities (Wong et al, 2010; Peelle et al, 2011; Eckert et al, 2012; Lin et al, 2014). Concerning the influence of hearing device treatment, there is evidence for rapid adaptation in auditory cortex following cochlear implantation. Hwang et al (2006) fitted bilaterally hearing-impaired participants with unilateral HAs and measured blood-oxygen-level dependent (BOLD) responses using functional magnetic resonance imaging (fMRI). After 3 months of HA use, their participants showed a bilateral decrease in brain activation in auditory cortex (i.e., superior temporal gyrus)

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