An Exploratory Study of the Effect of Tinnitus on Listening Effort Using EEG and Pupillometry

Abstract

Objective: Previous behavioral studies on listening effort in tinnitus patients did not consider extended high-frequency hearing thresholds and had conflicting results. This inconsistency may be related that listening effort is not evaluated by the central nervous system (CNS) and autonomic nervous system (ANS), which are directly related to tinnitus pathophysiology. This study matches hearing thresholds at all frequencies, including the extended high-frequency and reduces hearing loss to objectively evaluate listening effort over the CNS and ANS simultaneously in tinnitus patients.

Study design: Case-control study.

Setting: University hospital.

Methods: Sixteen chronic tinnitus patients and 23 matched healthy controls having normal pure-tone averages with symmetrical hearing thresholds were included. Subjects were evaluated with 0.125 to 20 kHz pure-tone audiometry, Montreal Cognitive Assessment Test (MoCA), Tinnitus Handicap Inventory (THI), Visual Analog Scale (VAS), electroencephalography (EEG), and pupillometry.

Results: Pupil dilation and EEG alpha band in the "coding" phase of the sentence presented in tinnitus patients was less than in the control group (p < .05). VAS score was higher in the tinnitus group (p < .01). Also, there was no statistically significant relationship between EEG and pupillometry components and THI or MoCA (p > .05).

Conclusion: This study suggests that tinnitus patients may need to make an extra effort to listen. Also, pupillometry may not be sufficiently reliable to assess listening effort in ANS-related pathologies. Considering the possible listening difficulties in tinnitus patients, reducing the listening difficulties, especially in noisy environments, can be added to the goals of tinnitus therapy protocols.

Keywords: extended high frequencies; listening effort; pupillometry; tinnitus.