2019 Conference on Implantable Auditory Prostheses

14-19 July 2019

Granlibakken, Lake Tahoe

Page 306

TH34: USING OBJECTIVE MEASURES TO REVEAL LISTENING EFFORT IN

COCHLEAR IMPLANT LISTENERS

Xin Zhou, Emily Burg, Alan Kan, Ruth Y. Litovsky

University of Wisconsin-Madison, Waisman Center; Department of Communication Sciences and Disorders,

Madison, WI, USA

Cochlear implants (CIs) help restore speech perception in people who have severe-to-profound

hearing loss in one, or both, ears. However, the CI input is degraded and thus more challenging

to understand than acoustic input in normal hearing. What is not well-understood is how effortful

listening is with CIs. In this work, we investigate two objective measures that can hopefully shed

light on this question. The first measure is of cortical activity using functional near-infrared

spectroscopy (fNIRS). This is a non-invasive method, whereby near-infrared light is used to

measure neural activity related changes in oxygen matablosim in the blood flow. fNIRS

responses are examined in the a-priori determined brain region of interest (ROI). In this work,

we focused on the bilateral inferior frontal gyrus (IFG), because other neuroimaging studies

have identified that region as being involved in effortful listening. The second measure is task-

evoked pupillometry. Previous work has shown that changes in pupil dilation correlate with task

engagement and listening effort. The purpose of this study is to conduct measures from fNIRS

and pupillometry in separate sessions, using similar tasks, to understand whether these

measures reveal similar findings regarding listening effort across different hearing conditions.

The study design is to test CI users while listening to speech sentences in quiet. Normal-hearing

(NH) participants are tested with vocoded speech. To increase task difficulty, two stimulus

variables are manipulated in which the sentence structure and difficulty levels are varied.

This study aims to test the hypothesis that two measures of listening effort, fNIRS in IFGs, and

Pupillometry, while listeners are engaged in similar tasks, would show consistent pattern of

responses between different hearing conditions.