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Date of Graduation
Doctor of Philosophy (PhD)
Department of Communication Sciences and Disorders
The main objective of the study is to compare the effectiveness of pupillometry, working memory and subjective rating scale —the physiological, behavioral, and subjective measures of listening effort— at different signal to noise ratios (SNR) and presentation levels: when administered together. Eleven young normal hearing individuals with mean age of 21.7 years (SD=1.9 years) participated in the study. The HINT sentences were used for speech perception in noise task. The listening effort was quantified using peak pupil dilation, working memory, working memory difference, subjective rating of listening and recall effort. The rating of perceived performance, frustration level and disengagement were also obtained. Using a repeated measure design, we examined how SNR (+6 dB to -10 dB) and presentation level (50- and 65-dB SPL) affect listening effort. Tobii eye-tracker software and custom MATLAB programing were used for stimulus presentation and data analysis. SNR had significant effect on peak pupil dilation, working memory, working memory difference, and subjective rating of listening effort. Speech intelligibility had significant correlation with all of the listening effort measures except working memory difference. The listening effort measures did not correlate significantly when controlled for speech intelligibility indicating different underlying constructs. When effect sizes are compared working memory (η2p = 0.98) was most sensitive to SNR effect, followed by subjective rating of listening effort (η2p = 0.84), working memory difference (η2p = 0.52) and peak pupil dilation (η2p = 0.40). Only peak pupil dilation showed significant effect of presentation level. The physiological, behavioral and subjective measures of listening effort have different underlying constructs and the sensitivity of these measures varies in representing the effect of SNR and presentation level. The individual data trend analysis shows different breakdown points for physiological and behavioral and subjective measures. There is a need to further explore the relationship of listening effort measures across different SNRs also how these relationship changes in persons with hearing loss.
Magudilu Srishyla Kumar, Lakshmi, "Measuring listening effort using physiological, behavioral and subjective methods in normal hearing subjects: Effect of signal to noise ratio and presentation level" (2020). Dissertations, 2020-current. 7.