Pupil and brain response to degraded speech (Zekveld et al., 2024)
Creators: name: Zekveld, Adriana A.
name: Kramer, Sophia
name: J. Heslenfeld, Dirk
name: Versfeld, Niek J.
name: Vriend, Chris
Publisher: name: ASHA journals
Year: 2024
Subjects: classificationCode: 420102
subject: Audiology
classificationCode: 460212
subject: Speech recognition
classificationCode: 520203
subject: Cognitive neuroscience

description: <b>Purpose: </b>A relevant aspect of listening is the effort required during speech processing, which can be assessed by pupillometry. Here, we assessed the pupil dilation response of normal-hearing (NH) and hard of hearing (HH) individuals during listening to clear sentences and masked or degraded sentences. We combined this assessment with functional magnetic resonance imaging (fMRI) to investigate the neural correlates of the pupil dilation response.<b>Method: </b>Seventeen NH participants (<i>M</i><sub>age</sub> = 46 years) were compared to 17 HH participants (<i>M</i><sub>age</sub> = 45 years) who were individually matched in age and educational level. Participants repeated sentences that were presented clearly, that were distorted, or that were masked. The sentence intelligibility level of masked and distorted sentences was 50% correct. Silent baseline trials were presented as well. Performance measures, pupil dilation responses, and fMRI data were acquired.<b>Results: </b>HH individuals had overall poorer speech reception than the NH participants, but not for noise-vocoded speech. In addition, an interaction effect was observed with smaller pupil dilation responses in HH than in NH listeners for the degraded speech conditions. Hearing impairment was associated with higher activation across conditions in the left superior temporal gyrus, as compared to the silent baseline. However, the region of interest analysis indicated lower activation during degraded speech relative to clear speech in bilateral frontal regions and the insular cortex, for HH compared to NH listeners. Hearing impairment was also associated with a weaker relation between the pupil response and activation in the right inferior frontal gyrus. Overall, degraded speech evoked higher frontal activation than clear speech.<b>Conclusion: </b>Brain areas associated with attentional and cognitive-control processes may be increasingly recruited when speech is degraded and are related to the pupil dilation response, but this relationship is weaker in HH listeners.<b>Supplemental Material S1.</b> Condition and group effects on the blood-oxygen level dependent (BOLD) response.<b>Supplemental Material S2. </b>Areas in which activation was positively associated with increasing mean pupil dilation responses.<b>Supplemental Material S3.</b> Pearson correlation coefficients between PTA, the mean pupil response and BOLD response difference for degraded speech &gt; clear speech.<b>Supplemental Material S4.</b> Relationship (fitted regression line) between the activation in the left lateral orbitofrontal gyrus evoked by degraded speech relative to clear speech (degraded speech – clear speech) and the mean pure tone average hearing thresholds (across 500, 1000, 2000, 4000 Hz, and both ears) in dB HL.Zekveld, A. A., Kramer, S. E., Heslenfeld, D. J., Versfeld, N. J., &amp; Vriend, C. (2024). Hearing impairment: Reduced pupil dilation response and frontal activation during degraded speech perception. <i>Journal of Speech, Language, and Hearing Research</i><i>, 67</i>(11), 4549–4566. https://doi.org/10.1044/2024_JSLHR-24-00017