Input-related demands: vocoded sentences evoke different pupillometrics and subjective listening effort than sentences in speech-shaped noise

Abstract

Objectives

The Framework for Effortful Listening (FUEL) suggests five input-related demands can alter listening effort: source, transmission, listener, message and context factors. We hypothesised that vocoded sentences represented a source factor degradation and sentences in speech-shaped noise represented a transmission factor degradation. We used pupillometry and a subjective scale to examine our hypothesis.

Design

Participants listened to vocoded sentences and sentences in speech-shaped noise at several difficulty levels designed to produce similar word recognition abilities; they also listened to unprocessed sentences. Within-participant pupillometrics and subjective listening effort were analysed. Post-hoc analyses were performed to examine if word recognition accuracy differentially influenced pupil responses.

Study samples

Twenty young adults with normal hearing.

Results

Baseline pupil diameter was significantly smaller, peak pupil dilation was significantly larger, peak pupil dilation latency was significantly shorter, and subjective listening effort was significantly greater for the vocoded sentences than the sentences-in-noise. Word recognition ability also affected pupillometrics, but only for the vocoded sentences.

Conclusions

Our findings suggest that source factor degradations result in greater listening effort than transmission factor degradations. Future research should address how clinical interventions tailored towards different input-related demands may lead to reduced listening effort and improve patient outcomes.

Keywords:

• Listening effort
• pupillometrics
• pupillometry
• input-related demands
• vocoded

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Funding was provided by NIDILRR (National Institute on Disability, Independent Living, and Rehabilitation Research) 90REGE0013. The content of this article does not represent the views of the United States government or the Department of Veterans Affairs.