SLPOtherTrends in hearing2025

Listening Effort for Soft Speech in Quiet.

Hendrik Husstedt, Jennifer Schmidt, Luca Wiederschein and 3 others

PMID 40827039

WHAT IT FOUND

Soft speech in quiet was rated as requiring no effort only at 40 dB SPL on average.

In normal-hearing adults, it was understandable at around 22 dB SPL but still felt effortful.

Key findings

01In quiet, normal-hearing participants rated speech as requiring extreme effort at 19.4 dB SPL, about 85% intelligibility, and no effort at 40 dB SPL.

02Pupil size was largest at 13 to 16 dB SPL and smallest at 27 to 34 dB SPL.

03In the follow-up, threshold-simulating noise shifted effort ratings toward the quiet pattern but less strongly than quiet itself.

STILL TO COME

How it was doneWhat they foundWhat it means for SLPs

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What it does not show

20 adults aged 18 to 35 years in the main experiment and 18 adults aged 19 to 29 years in the follow-up had normal hearing, so the study does not show how people with hearing loss respond. The tasks used meaningless German sentences in a sound booth, so everyday conversation and other languages were not tested. No treatment or hearing aid was tested, so the study cannot show that amplification reduces effort. During pupil testing, intelligibility scores at the intended 20%, 50%, and 80% levels were 28.5%, 63.7%, and 86.4%, so the condition labels did not exactly match what participants heard. The rise in pupil size at 60 dB SPL may reflect a startling, arousal, or loudness effect rather than listening effort.

Declared interests

The authors reported no financial support for the research, authorship, or publication, and no potential conflicts of interest.

The easy way to misread this

Do not read this as evidence that amplifying soft speech helps patients. The study tested normal-hearing adults in a laboratory and did not test hearing aids, treatment, or people with hearing loss.

Read it on PubMed →