The effects of noise attenuation
on listening effort and arousal
1Sindri Jonsson, 1Emil Bjergskov Larsen, 2Torben Christiansen,
1Elaine Hoi Ning Ng, 1Andreea Micula
1Oticon A/S, Smørum, Denmark; 2EPOS, Ballerup, Denmark

Pupil dilation:

Introduction
Previous studies have shown that sub-optimal listening conditions
may affect listening effort1 and arousal2 for individuals with normal
hearing3. In these studies, speech-in-noise tasks have been usedand quantified via speech recognition performance, subjective
ratings and pupil responses. The objective of the present study wasto investigate the effect of noise attenuation on listening effort andarousal in persons with normal hearing.

Methods
Participants:• 19 persons with self-reported normal hearing (8 female)• Aged between 22 and 53 years (mean age = 36, SD = 10)

Figure 2: Pupillometric results, PPD (left) and baseline (right), for each noise condition and pre/post-loadtask combinations. Error bars show standard errors. ANOVA of PPD revealed significant main effect ofnoise condition (p<0.05), while ANOVA of baseline revealed significant main effect of pre- and post-loadtask (p<0.01).

Study design:• Within subject design performing pre- and post-load speech-innoise tasks3

Applying the same analysis using mean pupil dilation (MPD)
showed the same behavior as in PPD, with a significant main effectof noise attenuation (p<0.05).

• 40 DAT sentences4, adjusted to SRT80, with and without noise
attenuation in the pre- and post-load tasks

Subjective ratings:• The load task consisted of 14 SWIR lists5 with -1 dB SNR, halfwith and half without noise attenuation in random order• 4-talker babble noise in all speech-in-noise tasks

Figure 1: Diagram of the study design and procedure.

Metrics:• Pupil dilation, where peak pupil dilation (PPD) and baseline pupildilation (BPD) were measured to assess listening effort andarousal, respectively

Figure 3: Subjective ratings for each noise condition and pre/post-load task combinations. Error bars
show standard errors. ANOVA of ‘Invested effort’ revealed significant main effect of noise condition(p<0.001). Friedman ANOVA of the combinations in ‘Perceived performance’ and ’Tendency to quit’
showed significant difference (p<0.05). Post-hoc analysis revealed significant differences between
combinations that differed in noise condition (p<0.001).

• Speech recognition performance• Subjective ratings reported after pre- and post-load tasks foreach noise condition:
1. Invested effort

Discussion and conclusions
Noise attenuation significantly reduces listening effort.
• Evident from subjective rating of invested effort, the objective

2. Perceived performancemeasure from PPD, and their agreement.

3. Tendency to quit

Baseline significantly decreases from pre- to post-load task.

Results• Likely not related to fatigue, as speech recognition does not

Speech recognition:

decrease from pre- and post-load tasks.
• Possibly due to heightened anticipatory arousal in the pre-load±±±±task, which then may decrease by re-evaluation of task demandor increasing task familiarity.

Table 1: Speech recognition score with standard error for each combination of noise conditions andpre/post-load task combinations. Friedman ANOVA revealed a significant difference between thecombinations (p<0.05). Post-hoc analysis revealed significant differences between combinations thatdiffered in noise condition (p<0.001).

Contact: sios@oticon.com

References:
1 Wendt D, Dau T and Hjortkjær J (2016) Impact of Background Noise and Sentence Complexity on Processing Demands during Sentence Comprehension. Front. Psychol. 7:345.
2 Wang, Y., Naylor, G., Kramer, S. E., Zekveld, A. A., Wendt, D., Ohlenforst, B., & Lunner, T. (2018). Relations between self-reported daily-life fatigue, hearing status, and pupil dilation during a speechThis study was funded by EPOS

perception in noise task. Ear and Hearing, 39(3), 573.
3 Menase, D. A., Richter, M., Wendt, D., Fiedler, L., & Naylor, G. (2022). Task-Induced Mental Fatigue and Motivation Influence Listening Effort as Measured by the Pupil Dilation in a Speech-in-Noise
Task. medRxiv.
4 Bo Nielsen, J., Dau, T., & Neher, T. (2014). A Danish open-set speech corpus for competing-speech studies. The Journal of the Acoustical Society of America, 135(1), 407-420.
5 Ng, E. H. N., Rudner, M., Lunner, T., Pedersen, M. S., & Rönnberg, J. (2013). Effects of noise and working memory capacity on memory processing of speech for hearing-aid users. International
Journal of Audiology, 52(7), 433-441.