The Intelligibility-Based Repeat-Recall Test: I. Bayesian-Guided Estimation of Multiple Speech Reception Thresholds.

Advantages of Fluctuating Noise for Measuring Speech Intelligibility in Listeners With Hearing Loss

Measures of speech intelligibility in noise show limited correspondence with difficulties people with hearing loss report from daily life. This mismatch suggests that standard measurement conditions do not sufficiently capture aspects that are relevant for speech perception, such as dip listening and spatial release from masking. In the present study we developed and evaluated a test condition that incorporates these aspects and compared it with a standard condition. Speech intelligibility was measured in 100 participants with normal hearing (NH, N=17) and hearing loss (HL, N=83) ranging from mild to severe. Measurements were conducted using the German matrix sentence test (OLSA) in the standard condition with frontal presentation of stationary noise co-located with the target speech, and the proposed condition with fluctuating, speech-like maskers spatially separated (±60°) from the target. Stimuli were presented via headphones using virtual acoustics. Tests were performed unaided and with individualized amplification. The proposed condition revealed reduced speech intelligibility also for listeners with HL that showed close-to-normal speech intelligibility in the standard condition. With individualized amplification, more listeners with HL showed reduced speech intelligibility compared to NH listeners than in the standard condition. Benefit of amplification varied widely across individuals with similar hearing thresholds, with some listeners showing little or no benefit. The advantages of the proposed condition were driven by masker fluctuations rather than by spatial separation of sound sources. These findings demonstrate that speech intelligibility measurements incorporating fluctuating maskers provide potentially relevant information beyond standard assessments and can support a more individualized assessment of hearing loss.

The Temporal Resolution Needed for Speech Intelligibility Assessed with Mosaic Speech: Effects of Block Duration, Age, and Word Familiarity

Background/Objectives: Mosaic speech was used to further investigate the auditory system’s temporal resolution needed for speech intelligibility. Mosaic speech is a form of degraded speech segmented in frequency × time blocks with no discernible temporal fine structure and with degraded amplitude envelope cues. Methods: We performed a listening experiment with mosaic speech consisting of 20 frequency bands segmented into 20, 40, 80, 160, and 320 ms. Younger listeners (<25 years; n = 20), with self-reported normal hearing and having passed a limited screening test, and elderly listeners (>65 years; n = 19) with hearing thresholds ranging from normal hearing to moderate hearing loss listened to Japanese low- and high-familiarity mosaic words and wrote down what they heard. The original words were included as control stimuli. Results: Although younger listeners had significantly higher intelligibility scores, elderly listeners could integrate and parse coarse blocks of mosaic speech of 20 ms and 40 ms with intelligibility scores of 84% or higher for high-familiarity words. For longer block durations, however, the elderly listeners’ intelligibility dropped rapidly for both high- and low-familiarity words. In both the young and the elderly listener groups, intelligibility reached the floor for block durations of 160 and 320 ms. Word familiarity strongly affected intelligibility scores. For blocks up to 80 ms, intelligibility was significantly higher for high-familiarity words than for low-familiarity words in both age groups, with a 10–30% difference. Conclusions: Elderly listeners (n = 19) with normal hearing to moderate hearing loss could maintain relatively high intelligibility for mosaic words segmented in blocks of 20 or 40 ms, provided the words had a high familiarity level.

Predicting performance on the digits-in-noise test in noise and reverberation using the speech transmission index.

This study investigated the effects of noise and reverberation on recognition of Dutch digits-in-noise (DIN) test triplets. The findings demonstrate that the STIDIN, an adaptation to the standard speech transmission index (STI), provides a reliable, low‑error predictor of DIN test performance in conditions with noise and/or reverberation when only a single speech recognition threshold (SRT) measurement in noise is completed. To achieve this, twenty-four normal-hearing (NH) adults completed adaptive SRT measurements in noise-only, reverberation-only and combined noise and reverberation conditions using unprocessed (UP), low-pass filtered (LPF) and cochlear implant vocoded (CIvoc) speech materials. Standard STI values differed across conditions and overestimated the detrimental effect of reverberation on recognition. The STIDIN, derived from the magnitude cross power spectrum (mCPS) of reverberated DIN test triplets and unprocessed triplets, was applicable for T60 reverberation times up to 12 s. STIDIN values remained constant across conditions, showing no significant main effect of condition for any of the unprocessed and processed speech materials. The results show that when an SRTn measurement in noise-only is obtained using DIN test triplets (i.e., the clinical standard), the STIDIN can be used to predict the SRT in other listening conditions with noise and reverberation. The root‑mean‑square error between measured and predicted SRTs was 0.92 dB, and 95 % of predictions deviated <1.7 dB from the measured values in conditions with noise and/or reverberation.

Noise induced hearing loss: Screening with pure-tone audiometry and speech-in-noise testing

Speech intelligibility performance while wearing three different hearing protective devices

Purpose: This study was designed primarily to investigate the differences in speech-in-noise comprehension in normal hearing listeners while wearing passive low-pass foam earplugs (3M E-A-R), passive flat-attenuating earplugs (Etymotic Research ER-20), and active flat-attenuating adaptive earplugs (MusicPro MP9-15). All three earplugs have a similar attenuation of 13-15 dB. Furthermore, the study compared speech-in-noise comprehension with and without the use of earplugs. Lastly, the study assessed the subjective sound quality and comfort associated with each of the above-mentioned earplugs. Methods: The study employed a single group, non-randomized quasi-experimental design involving 33 participants with normal hearing. Each participant underwent a detailed audiometric evaluation to confirm normal auditory function. The evaluation included tympanometry, otoacoustic emissions, pure-tone testing, speech recognition, word recognition, and assessment of uncomfortable listening levels. Following the audiometric assessment, participants engaged in four rounds of speech-in-noise testing under sound field conditions. The tests administered were the QuickSIN and Words-in-Noise (WIN) tests. In one round, participants performed the tests without hearing protection at 80 dB HL. The other three rounds were conducted at 95 dB HL, with participants wearing each of the three different earplugs. To ensure consistency and reduce bias, all earplugs were fitted by a trained investigator, the order of the four rounds of testing was randomized, and all participants were blinded to the specific earplugs being used. Upon completion of each speech test battery, and while still blinded to the earplug type, participants rated both the sound quality and comfort of each earplug using a Likert scale ranging from 1 to 5. Results: The ER-20 and MP9-15 earplugs performed similarly to one another, with no statistically significant difference between them. However, both the ER-20 and MP9-15 earplugs statistically outperformed the 3M E-A-R earplugs. The MP9-15 earplugs yielded the highest mean percent correct scores on the WIN test (83.42%, 95% CI: 81.80-85.05), closely followed by the ER-20 earplugs (82.58%, 95% CI: 80.80-84.35). In contrast, the 3M E-A-R earplugs produced lowest mean percent correct scores (74.21%, 95% CI: 72.79-75.63). When comparing these results to the no hearing protection condition, which had a mean percent correct score of 83.09% (95% CI: 81.46-84.72), no significant differences were noted between the No HPD, ER-20, and MP9-15 conditions. However, all three of these conditions showed statistically significant improvements in speech-in-noise comprehension over the 3M E-A-R earplugs. A similar pattern of findings was observed in the QuickSIN segment of the test battery which can be viewed in detail in the study's results section. In terms of subjective ratings, both the ER-20 (mean score: 4.36; 95% CI: 4.12-4.61) and MP9-15 (mean score: 4.42; 95% CI: 4.19-4.66) earplugs received significantly higher evaluations for sound quality compared to the 3M E-A-R earplugs (mean score: 3.06; 95% CI: 2.70-3.43). Additionally, no statistically significant differences were observed among the three earplug types with respect to comfort ratings. Conclusions: The study found evidence that utilizing passive flat-attenuating ER-20 earplugs, and active flat-attenuating MP9-15 earplugs provide better speech understanding in noise for normal hearing listeners compared to wearing passive low-pass foam 3M E-A-R earplugs. The study also demonstrated that there was no observed difference in speech intelligibility between not wearing hearing protection and using ER-20 or MP9-15 earplugs. Furthermore, both the ER-20 and MP9-15 earplugs were regarded as providing higher sound quality than the traditional 3M E-A-R foam earplugs. Lastly, no significant differences in subjective comfort were identified among the various earplugs tested.

The effect of clear speech on dual-task measures of listening effort in varied noise levels

Listener-oriented clear speech (CS) improves word recognition in noise compared to conversational speech (CO). Pupillometry studies suggest that this intelligibility benefit may result from reduced listening effort, reflecting differences in how cognitive resources are allocated during challenging listening tasks. Dual-task paradigms demonstrate validity at measuring listening effort (Brown, 2025); however, previous studies have not consistently shown a CS benefit in response times on secondary visual tasks (Meemann and Smiljanić, 2019). The current study evaluates whether a CS benefit on visual task response time, and thus listening effort, emerges across different noise levels: quiet, 0 dB signal-to-noise ratio (SNR), and −5 dB SNR. Native English listeners performed a word recognition in noise task and a visual Stroop task, first separately and then simultaneously. Preliminary results show improved word recognition and slower response time with increased noise levels for CS but not for CO. However, response time did not improve with CS at any noise level. Thus, it appears that CS does not provide a measurable benefit for dual-task measures of listening effort, suggesting that cognitive resources may not be more available for the visual task when listening to the more intelligible CS.