Pupillometry Reflects Listening Effort as a Function of Talker in the AzBio Sentences

Background: Pupillometry, or the quantification of pupil size, reflects a variety of processes involved in listening effort and is sensitive to many cognitive demands even when word recognition abilities are high. However, it is uncommon for studies to use clinical tests to examine listening effort, which increases barriers for audiologists seeking to apply this information to their clinical practice. The AzBio sentences present a unique opportunity to use a clinical test to categorize a common concern reported by patients: certain talkers are more difficult to understand than others. Purpose: The purpose of this exploratory study was to parse the effects of condition (i.e., quiet vs. 10-talker babble), hearing status, and talker on listening effort by using pupillometry. Research Design: Within-participants cross-sectional design. Study Sample: Fifty-one adults were recruited for this prospective study. Twenty-two participants had no hearing loss, and 29 exhibited a three-frequency (1000-, 2000-, and 4000-Hz) pure tone average greater than 20 decibels hearing level (dB HL) but less than 70 dB HL. Of the participants with hearing loss, 18 wore hearing aids. Data Collection and Analysis: Changes in pupil dilation were measured using a remote eye tracker as participants listened to and repeated back AzBio sentences spoken by four distinct talkers: Male1, Male2, Female1, and Female2. Statistical analyses were performed on pupil dilation using linear mixed effects modeling and growth curve analysis (GCA). Results: Peak pupil dilation was largest for the participants with hearing loss who did not wear hearing aids. Peak dilations were also largest when participants listened to Male1 in 10-talker babble. GCA demonstrated that mean pupil diameter was larger for both male talkers than for the female talkers, and the linear growth rate of pupil dilation was significantly slower for participants without hearing loss. Conclusions: This study demonstrated that despite high word recognition abilities, unaided hearing loss and specific male talkers increased listening effort when participants listened to AzBio sentences. Clinical Relevance Statement: These results will be of interest to clinicians who are interested in learning about how listening effort contributes to patient-reported difficulties in clinical practice.