Reception Thresholds For Sentences Research Articles

Binaural pre-processing for contralateral sound field attenuation can improve speech-in-noise intelligibility for bilateral hearing-aid users

We have recently proposed a binaural sound pre-processing method to attenuate sounds contralateral to each ear and shown that it can improve speech intelligibility for normal-hearing (NH) people in simulated “cocktail party” listening situations (Lopez-Poveda et al., 2022, Hear Res 418:108,469). The aim here was to evaluate if this benefit remains for hearing-impaired listeners when the method is combined with two independently functioning hearing aids, one per ear. Twelve volunteers participated in the experiments; five of them had bilateral sensorineural hearing loss and seven were NH listeners with simulated bilateral conductive hearing loss. Speech reception thresholds (SRTs) for sentences in competition with a source of steady, speech-shaped noise were measured in unilateral and bilateral listening, and for (target, masker) azimuthal angles of (0°, 0°), (270°, 45°), and (270°, 90°). Stimuli were processed through a pair of software-based multichannel, fast-acting, wide dynamic range compressors, with and without binaural pre-processing. For spatially collocated target and masker sources at 0° azimuth, the pre-processing did not affect SRTs. For spatially separated target and masker sources, the pre-processing improved SRTs when listening bilaterally (improvements up to 10.7 dB) or unilaterally with the acoustically better ear (improvements up to 13.9 dB), while it worsened SRTs when listening unilaterally with the acoustically worse ear (decrements of up to 17.0 dB). Results show that binaural pre-processing for contralateral sound attenuation can improve speech-in-noise intelligibility in laboratory tests also for bilateral hearing-aid users.

Differences in Force Levels, Word Recognition in Quiet, Sentence Reception Threshold in Noise, and Subjective Outcomes for a Bone-Anchored Hearing Device Programmed Using Manufacturer First-Fit, Aided Sound-Field Thresholds and Programmed to DSL-BCD Using a Skull Simulator.

Best practice guidelines for verifying fittings of bone-anchored hearing devices (BAHD) recommend using aided sound-field thresholds (ASFT), but express caution regarding the variables impacting obtaining valid and reliable ASFTs.1 Recently, a skull simulator was introduced to facilitate programming BAHD devices in force level (FL) to desired sensation level-bone conduction devices (skull simulator/DSL-BCD)2 3 targets in a hearing aid analyzer. Currently, no evidence is available reporting if differences in measured FL using the manufacturer first-fit (FF) and word recognition in quiet, sentence reception threshold in noise, and subjective outcomes are present for a BAHD programmed using ASFT versus programmed using skull simulator/DSL-BCD targets. The aim of this study was to examine if significant differences were present in FL using the FF and word recognition in quiet at 50 and 65 decibel of sound pressure level (dB SPL), sentence reception threshold in noise and subjective outcomes using the abbreviated profile of hearing aid benefit (APHAB), and speech, spatial, and qualities of hearing (SSQ) between a BAHD fit using ASFT or skull simulator/DSL-BCD targets. A double-blind randomized crossover design with 15 adults having unilateral sensorineural hearing loss. All participants were successful users of the Cochlear America Baha 5. Baha Power 5 devices were fit using FF, ASFT, and skull simulator/DSL-BCD targets. Order of the three fitting strategies was randomly assigned and counter-balanced. No significant differences were found for a BAHD device programmed using ASFT versus skull simulator/DSL-BCD targets for consonant-nucleus-consonant words in quiet at 50 or 65 dB SPL, sentence reception threshold in noise, the APHAB or SSQ. There were, however, significant differences, at primarily 500 to 2,000 Hz in measured FLs between the FF, ASFT, and skull simulator/DSL-BCD targets at 50 and 65 dB SPL. There were no significant differences in subject performance with two speech measures and subjective responses to two questionnaires for BAHD fittings using ASFT versus using skull simulator/DSL-BCD targets. Differences in FL between the three fitting strategies were present primarily at 500 to 2,000 Hz. Limitations of the study are highlighted along with situations where the skull simulator can play a significantly beneficial role when fitting BAHD devices.

Speech-in-Noise Recognition With More Realistic Implementations of a Binaural Cochlear-Implant Sound Coding Strategy Inspired by the Medial Olivocochlear Reflex.

Objectives:Cochlear implant (CI) users continue to struggle understanding speech in noisy environments with current clinical devices. We have previously shown that this outcome can be improved by using binaural sound processors inspired by the medial olivocochlear (MOC) reflex, which involve dynamic (contralaterally controlled) rather than fixed compressive acoustic-to-electric maps. The present study aimed at investigating the potential additional benefits of using more realistic implementations of MOC processing.Design:Eight users of bilateral CIs and two users of unilateral CIs participated in the study. Speech reception thresholds (SRTs) for sentences in competition with steady state noise were measured in unilateral and bilateral listening modes. Stimuli were processed through two independently functioning sound processors (one per ear) with fixed compression, the current clinical standard (STD); the originally proposed MOC strategy with fast contralateral control of compression (MOC1); a MOC strategy with slower control of compression (MOC2); and a slower MOC strategy with comparatively greater contralateral inhibition in the lower-frequency than in the higher-frequency channels (MOC3). Performance with the four strategies was compared for multiple simulated spatial configurations of the speech and noise sources. Based on a previously published technical evaluation of these strategies, we hypothesized that SRTs would be overall better (lower) with the MOC3 strategy than with any of the other tested strategies. In addition, we hypothesized that the MOC3 strategy would be advantageous over the STD strategy in listening conditions and spatial configurations where the MOC1 strategy was not.Results:In unilateral listening and when the implant ear had the worse acoustic signal-to-noise ratio, the mean SRT was 4 dB worse for the MOC1 than for the STD strategy (as expected), but it became equal or better for the MOC2 or MOC3 strategies than for the STD strategy. In bilateral listening, mean SRTs were 1.6 dB better for the MOC3 strategy than for the STD strategy across all spatial configurations tested, including a condition with speech and noise sources colocated at front where the MOC1 strategy was slightly disadvantageous relative to the STD strategy. All strategies produced significantly better SRTs for spatially separated than for colocated speech and noise sources. A statistically significant binaural advantage (i.e., better mean SRTs across spatial configurations and participants in bilateral than in unilateral listening) was found for the MOC2 and MOC3 strategies but not for the STD or MOC1 strategies.Conclusions:Overall, performance was best with the MOC3 strategy, which maintained the benefits of the originally proposed MOC1 strategy over the STD strategy for spatially separated speech and noise sources and extended those benefits to additional spatial configurations. In addition, the MOC3 strategy provided a significant binaural advantage, which did not occur with the STD or the original MOC1 strategies.

Effect of presentation level and age on release from masking: Behavioral measures.

The effect of presentation level and age on release from masking (RFM) was examined. Two speech-in-noise paradigms [i.e., fixed speech with varying signal-to-noise ratios (SNRs) and fixed noise with varying speech levels] were employed with competing continuous and interrupted noises. Young and older normal-hearing adults participated (N = 36). Word recognition was assessed at three presentation levels (i.e., 20, 30, and 40 dB sensation level) in SNRs of -10, 0, and 10 dB. Reception thresholds for sentences (RTSs) were determined at three presentation levels (i.e., 55, 65, and 75 dB sound pressure level). RTS SNRs were determined in both noises. RFM was computed by subtracting word recognition scores in continuous noise from interrupted noise and RTS SNRs in interrupted noise from continuous noise. Significant effects of presentation level, group, and SNR were seen with word recognition performance. RFM increased with increasing sensation level, was greater in younger adults, and was superior at -10 dB SNR. With RTS SNRs, significant effects of presentation level and group were found. The findings support the notion that RFM is a level dependent auditory temporal resolution phenomenon and older listeners display a deficit relative to younger listeners.

Relationship Between Auditory and Visual Noise Acceptance in Normal-Hearing Listeners.

Research has shown that hearing aid acceptance is closely related to how well an individual tolerates background noise, regardless of improved speech understanding in background noise. The acceptable noise level (ANL) test was developed to quantify background noise acceptance. The ANL test measures a listener's willingness to listen to speech in noise rather than their ability to understand speech in noise, and is clinically valuable as a predictor of hearing aid success. Noise acceptance is thought to be mediated by central regions of the nervous system, but the underlying mechanism of noise acceptance is not well understood. Higher order central efferent mechanisms may be weaker and/or central afferent mechanisms are more active in listeners with large versus small ANLs. Noise acceptance, therefore, may not be limited to the auditory modality but observable across modalities. We designed a visual-ANL test, as a parallel of the auditory-ANL test, to examine the relations between auditory and visual noise acceptance. A correlational design. Thirty-seven adults between the ages of 21 and 30 years with normal hearing participated in this study. All participants completed the standard auditory-ANL task, the visual-ANL task developed for this study, reception thresholds for sentences using the hearing in noise test, and visual sentence recognition in noise using the text reception threshold test. Correlational analyses were performed to evaluate the relations between and among the ANL and perception tasks. Auditory- and Visual-ANLs were correlated; those who accepted more auditory noise were also those who accepted more visual noise. Auditory and visual perceptual measures were also correlated, demonstrating that both measures reflect common processes underlying the ability to recognize speech in noise. Finally, as expected, noise acceptance levels were unrelated to perception in noise across modalities. The results of this study support our hypothesis that noise acceptance may not be unique to the auditory modality, specifically, that the common variance shared between the two ANL tasks, may reflect a shared general perceptual or cognitive mechanism that is not specific to the auditory or visual domains. These findings also support that noise acceptance and speech recognition reflect different aspects of auditory and visual perception. Future work will relate these ANL measures with central tasks of inhibition and include hearing-impaired individuals to explore the mechanisms underlying noise acceptance.

Speech-in-Noise and Quality-of-Life Measures in School-Aged Children With Normal Hearing and With Unilateral Hearing Loss.

(1) Measure sentence recognition in co-located and spatially separated target and masker configurations in school-aged children with unilateral hearing loss (UHL) and with normal hearing (NH). (2) Compare self-reported hearing-related quality-of-life (QoL) scores in school-aged children with UHL and NH. Listeners were school-aged children (6 to 12 yrs) with permanent UHL (n = 41) or NH (n = 35) and adults with NH (n = 23). Sentence reception thresholds (SRTs) were measured using Hearing In Noise Test-Children sentences in quiet and in the presence of 2-talker child babble or a speech-shaped noise masker in target/masker spatial configurations: 0/0, 0/-60, 0/+60, or 0/±60 degrees azimuth. Maskers were presented at a fixed level of 55 dBA, while the level of the target sentences varied adaptively to estimate the SRT. Hearing-related QoL was measured using the Hearing Environments and Reflection on Quality of Life (HEAR-QL-26) questionnaire for child subjects. As a group, subjects with unaided UHL had higher (poorer) SRTs than age-matched peers with NH in all listening conditions. Effects of age, masker type, and spatial configuration of target and masker signals were found. Spatial release from masking was significantly reduced in conditions where the masker was directed toward UHL subjects' normal-hearing ear. Hearing-related QoL scores were significantly poorer in subjects with UHL compared to those with NH. Degree of UHL, as measured by four-frequency pure-tone average, was significantly correlated with SRTs only in the two conditions where the masker was directed towards subjects' normal-hearing ear, although the unaided Speech Intelligibility Index at 65 dB SPL was significantly correlated with SRTs in four conditions, some of which directed the masker to the impaired ear or both ears. Neither pure-tone average nor unaided Speech Intelligibility Index was correlated with QoL scores. As a group, school-aged children with UHL showed substantial reductions in masked speech perception and hearing-related QoL, irrespective of sex, laterality of hearing loss, and degree of hearing loss. While some children demonstrated normal or near-normal performance in certain listening conditions, a disproportionate number of thresholds fell in the poorest decile of the NH data. These findings add to the growing literature challenging the past assumption that one ear is "good enough."

Evidence for age-related cochlear synaptopathy in humans unconnected to speech-in-noise intelligibility deficits

Cochlear synaptopathy (or the loss of primary auditory synapses) remains a subclinical condition of uncertain prevalence. Here, we investigate whether it affects humans and whether it contributes to suprathreshold speech-in-noise intelligibility deficits. For 94 human listeners with normal audiometry (aged 12–68 years; 64 women), we measured click-evoked auditory brainstem responses (ABRs), self-reported lifetime noise exposure, and speech reception thresholds for sentences (at 65 dB SPL) and words (at 50, 65 and 80 dB SPL) in steady-state and fluctuating maskers. Based on animal research, we assumed that the shallower the rate of growth of ABR wave-I amplitude versus level function, the higher the risk of suffering from synaptopathy. We found that wave-I growth rates decreased with increasing age but not with increasing noise exposure. Speech reception thresholds in noise were not correlated with wave-I growth rates and mean speech reception thresholds were not statistically different for two subgroups of participants (N = 14) with matched audiograms (up to 12 kHz) but different wave-I growth rates. Altogether, the data are consistent with the existence of age-related but not noise-related synaptopathy. In addition, the data dispute the notion that synaptopathy contributes to suprathreshold speech-in-noise intelligibility deficits.

Hearing Loss in Children With Otitis Media With Effusion: Actual and Simulated Effects on Speech Perception.

Conductive hearing loss simulations have attempted to estimate the speech-understanding difficulties of children with otitis media with effusion (OME). However, the validity of this approach has not been evaluated. The research aim of the present study was to investigate whether a simple, frequency-specific, attenuation-based simulation of OME-related hearing loss was able to reflect the actual effects of conductive hearing loss on speech perception. Forty-one school-age children with OME-related hearing loss were recruited. Each child with OME was matched with a same sex and age counterpart with normal hearing to make a participant pair. Pure-tone threshold differences at octave frequencies from 125 to 8000 Hz for every participant pair were used as the simulation attenuation levels for the normal-hearing children. Another group of 41 school-age otologically normal children were recruited as a control group without actual or simulated hearing loss. The Mandarin Hearing in Noise Test was utilized, and sentence recall accuracy at four signal to noise ratios (SNR) considered representative of classroom-listening conditions were derived, as well as reception thresholds for sentences (RTS) in quiet and in noise using adaptive protocols. The speech perception in quiet and in noise of children with simulated OME-related hearing loss was significantly poorer than that of otologically normal children. Analysis showed that RTS in quiet of children with OME-related hearing loss and of children with simulated OME-related hearing loss was significantly correlated and comparable. A repeated-measures analysis suggested that sentence recall accuracy obtained at 5-dB SNR, 0-dB SNR, and -5-dB SNR was similar between children with actual and simulated OME-related hearing loss. However, RTS in noise in children with OME was significantly better than that for children with simulated OME-related hearing loss. The present frequency-specific, attenuation-based simulation method reflected the effects of OME-related hearing loss on speech perception impairment in quiet environments. In noisy environments, the simulation method could only approximately estimate the effects of OME-related hearing loss on speech perception in typical classroom noise levels. Children with OME-related hearing loss may develop compensatory strategies to reduce the effects of hearing loss in adverse listening environments.

Involvement of the Efferent Auditory System for Improvement in Speech Perception in Noise

To investigate the involvement of auditory efferents in hearing-in-noise in humans, Median olivocochlear (MOC) efferent’s functioning and speech recognition-in-noise abilities were compared in 19 subjects. MOC efferent’s function was assessed in terms of contralateral attenuation of transient evoked otoacoustic emissions (TEOAE): i.e., the reduction in TEOAE amplitude elicited by a 40, 50 and 60-dB SPL contralateral speech spectrum shaped noise. Correspondingly, the speech reception thresholds for sentences embedded in 50-dB SPL speech spectrum shaped noise (SRTn) were measured in the same ear as the TEOAEs, successively in the presence and in the absence of uncorrelated noise in the opposite ear at three different levels (i.e 40, 50, & 60 dB SPL). The results indicated there was no significant statistical correlation between the contralateral attenuation of TEOAEs and SRTn for uncorrelated noise. In addition, there was no change in SRTn for uncorrelated noise at different levels. These results were discussed in line with previous studies.

Assessing the Relationship Between the Electrically Evoked Compound Action Potential and Speech Recognition Abilities in Bilateral Cochlear Implant Recipients.

The primary objective of the present study was to examine the relationship between suprathreshold electrically evoked compound action potential (ECAP) measures and speech recognition abilities in bilateral cochlear implant listeners. We tested the hypothesis that the magnitude of ear differences in ECAP measures within a subject (right-left) could predict the difference in speech recognition performance abilities between that subject's ears (right-left). To better control for across-subject variables that contribute to speech understanding, the present study used a within-subject design. Subjects were 10 bilaterally implanted adult cochlear implant recipients. We measured ECAP amplitudes and slopes of the amplitude growth function in both ears for each subject. We examined how each of these measures changed when increasing the interphase gap of the biphasic pulses. Previous animal studies have shown correlations between these ECAP measures and auditory nerve survival. Speech recognition measures included speech reception thresholds for sentences in background noise, as well as phoneme discrimination in quiet and in noise. Results showed that the between-ear difference (right-left) of one specific ECAP measure (increase in amplitude growth function slope as the interphase gap increased from 7 to 30 µs) was significantly related to the between-ear difference (right-left) in speech recognition. Frequency-specific response patterns for ECAP data and consonant transmission cues support the hypothesis that this particular ECAP measure may represent localized functional acuity. The results add to a growing body of literature suggesting that when using a well-controlled research design, there is evidence that underlying neural function is related to postoperative performance with a cochlear implant.

Benefits of incorporating the adaptive dynamic range optimization amplification scheme into an assistive listening device for people with mild or moderate hearing loss

ABSTRACTThis study investigated whether a self-designed assistive listening device (ALD) that incorporates an adaptive dynamic range optimization (ADRO) amplification strategy can surpass a commercially available monaurally worn linear ALD, SM100. Both subjective and objective measurements were implemented. Mandarin Hearing-In-Noise Test (MHINT) scores were the objective measurement, whereas participant satisfaction was the subjective measurement. The comparison was performed in a mixed design (i.e., subjects’ hearing status being mild or moderate, quiet versus noisy, and linear versus ADRO scheme). The participants were two groups of hearing-impaired subjects, nine mild and eight moderate, respectively. The results of the ADRO system revealed a significant difference in the MHINT sentence reception threshold (SRT) in noisy environments between monaurally aided and unaided conditions, whereas the linear system did not. The benchmark results showed that the ADRO scheme is effectively beneficial to people who experience mild or moderate hearing loss in noisy environments. The satisfaction rating regarding overall speech quality indicated that the participants were satisfied with the speech quality of both ADRO and linear schemes in quiet environments, and they were more satisfied with ADRO than they with the linear scheme in noisy environments.

The development and validation of the Closed-set Mandarin Sentence (CMS) test

Matrix-styled sentence tests offer a closed-set paradigm that may be useful when evaluating speech intelligibility. Ideally, sentence test materials should reflect the distribution of phonemes within the target language. We developed and validated the Closed-set Mandarin Sentence (CMS) test to assess Mandarin speech intelligibility in noise. CMS test materials were selected to be familiar words and to represent the natural distribution of vowels, consonants, and lexical tones found in Mandarin Chinese. Ten key words in each of five categories (Name, Verb, Number, Color, and Fruit) were produced by a native Mandarin talker, resulting in a total of 50 words that could be combined to produce 100,000 unique sentences. Normative data were collected in 10 normal-hearing, adult Mandarin-speaking Chinese listeners using a closed-set test paradigm. Two test runs were conducted for each subject, and 20 sentences per run were randomly generated while ensuring that each word was presented only twice in each run. First, the level of the words in each category were adjusted to produce equal intelligibility in noise. Test-retest reliability for word-in-sentence recognition was excellent according to Cronbach's alpha (0.952). After the category level adjustments, speech reception thresholds (SRTs) for sentences in noise, defined as the signal-to-noise ratio (SNR) that produced 50% correct whole sentence recognition, were adaptively measured by adjusting the SNR according to the correctness of response. The mean SRT was −7.9 (SE = 0.41) and −8.1 (SE = 0.34) dB for runs 1 and 2, respectively. The mean standard deviation across runs was 0.93 dB, and paired t-tests showed no significant difference between runs 1 and 2 (p = 0.74) despite random sentences being generated for each run and each subject. The results suggest that the CMS provides large stimulus set with which to repeatedly and reliably measure Mandarin-speaking listeners’ speech understanding in noise using a closed-set paradigm.

The Vibrant Soundbridge in Children and Adolescents: Preliminary European Multicenter Results.

Evaluation of safety and efficacy of the Vibrant Soundbridge in the treatment of hearing loss in children and adolescents with primary focus on improvement in speech discrimination. Prospective, single-subject repeated-measures design in which each subject serves as his/her own control. Tertiary referral center. Nineteen patients aged 5 to 17 years. Implantation of an active middle ear implant. Improvement in word recognition scores, speech reception thresholds, and signal-to-noise ratios (SNRs) were evaluated, in addition to air and bone conduction. Oldenburger Kids Satztest/Oldenburger Satztest sentences and Göttinger/Freiburger monosyllables at 65-dB hearing level were tested in two age groups. Significant speech discrimination improvement was seen in all patients after 6 months. In children 5 to 9 years old, mean monosyllable recognition improved from 28.9% (unaided) to 95.5% (Soundbridge-aided). Aided 50% sentence discrimination at 44.1 dB and SNR of -4.9 dB were measured. In patients 10 to 17 years old, mean word recognition improved from 18.5% to 89.0%, sentence reception threshold improved to 40.2 dB, and SNR to -3.6 dB. Comparison between age groups indicated a slight trend toward quicker adaptation by older subjects. However, after initial adjustment, a higher level of overall benefit was seen at 6 months in younger children. Currently, the only middle ear implant approved for pediatric patients, the Vibrant Soundbridge, provides an option in cases of congenital aural atresia or disease-induced defects, when surgical intervention and reconstruction is indicated. The 6-month results in this comparatively large study population validated conclusions found in previous trials.

Aided and unaided speech perception by older hearing impaired listeners.

The most common complaint of older hearing impaired (OHI) listeners is difficulty understanding speech in the presence of noise. However, tests of consonant-identification and sentence reception threshold (SeRT) provide different perspectives on the magnitude of impairment. Here we quantified speech perception difficulties in 24 OHI listeners in unaided and aided conditions by analyzing (1) consonant-identification thresholds and consonant confusions for 20 onset and 20 coda consonants in consonant-vowel-consonant (CVC) syllables presented at consonant-specific signal-to-noise (SNR) levels, and (2) SeRTs obtained with the Quick Speech in Noise Test (QSIN) and the Hearing in Noise Test (HINT). Compared to older normal hearing (ONH) listeners, nearly all unaided OHI listeners showed abnormal consonant-identification thresholds, abnormal consonant confusions, and reduced psychometric function slopes. Average elevations in consonant-identification thresholds exceeded 35 dB, correlated strongly with impairments in mid-frequency hearing, and were greater for hard-to-identify consonants. Advanced digital hearing aids (HAs) improved average consonant-identification thresholds by more than 17 dB, with significant HA benefit seen in 83% of OHI listeners. HAs partially normalized consonant-identification thresholds, reduced abnormal consonant confusions, and increased the slope of psychometric functions. Unaided OHI listeners showed much smaller elevations in SeRTs (mean 6.9 dB) than in consonant-identification thresholds and SeRTs in unaided listening conditions correlated strongly (r = 0.91) with identification thresholds of easily identified consonants. HAs produced minimal SeRT benefit (2.0 dB), with only 38% of OHI listeners showing significant improvement. HA benefit on SeRTs was accurately predicted (r = 0.86) by HA benefit on easily identified consonants. Consonant-identification tests can accurately predict sentence processing deficits and HA benefit in OHI listeners.

Speech Perception in Older Hearing Impaired Listeners: Benefits of Perceptual Training

Hearing aids (HAs) only partially restore the ability of older hearing impaired (OHI) listeners to understand speech in noise, due in large part to persistent deficits in consonant identification. Here, we investigated whether adaptive perceptual training would improve consonant-identification in noise in sixteen aided OHI listeners who underwent 40 hours of computer-based training in their homes. Listeners identified 20 onset and 20 coda consonants in 9,600 consonant-vowel-consonant (CVC) syllables containing different vowels (/ɑ/, /i/, or /u/) and spoken by four different talkers. Consonants were presented at three consonant-specific signal-to-noise ratios (SNRs) spanning a 12 dB range. Noise levels were adjusted over training sessions based on d’ measures. Listeners were tested before and after training to measure (1) changes in consonant-identification thresholds using syllables spoken by familiar and unfamiliar talkers, and (2) sentence reception thresholds (SeRTs) using two different sentence tests. Consonant-identification thresholds improved gradually during training. Laboratory tests of d’ thresholds showed an average improvement of 9.1 dB, with 94% of listeners showing statistically significant training benefit. Training normalized consonant confusions and improved the thresholds of some consonants into the normal range. Benefits were equivalent for onset and coda consonants, syllables containing different vowels, and syllables presented at different SNRs. Greater training benefits were found for hard-to-identify consonants and for consonants spoken by familiar than unfamiliar talkers. SeRTs, tested with simple sentences, showed less elevation than consonant-identification thresholds prior to training and failed to show significant training benefit, although SeRT improvements did correlate with improvements in consonant thresholds. We argue that the lack of SeRT improvement reflects the dominant role of top-down semantic processing in processing simple sentences and that greater transfer of benefit would be evident in the comprehension of more unpredictable speech material.

No Learning Effect Observed for Reception Thresholds for Sentences in Noise

This study examined reception thresholds for sentences (RTSs) as a function of test session (N = 5) and noise (continuous and interrupted) in normal-hearing adults. It was hypothesized that RTSs would be superior in interrupted noise and would be stable across repeated testing. Twenty-five normal-hearing adults participated. RTSs were determined with Hearing in Noise Test sentences in continuous and interrupted noise presented at 65 dBA. An adaptive technique was used where sentences varied in intensity to converge on a level of 50% of correct performance. Sentence lists were counterbalanced with 5 unique lists in both continuous and interrupted noise. RTS signal-to-noise ratios were significantly better in the interrupted noise (p < .0001). There was no effect of test session (p = .12) or a Test Session × Noise interaction (p = .13). Stable RTS signal-to-noise ratios across test sessions in both noises are consistent with the notion that a learning effect was not present in noise. Further, one may conclude that Hearing in Noise Test sentences provide stable measures of sentence recognition thresholds in normal-hearing adults over time so long as sentences are unique or are not repeated.

Effects of ageing and hearing thresholds on speech perception in quiet and in noise perceived in different locations.

Background and ObjectivesThis study investigated the effect of ageing on speech perception in quiet and in noise, with noise directed from front, right and left.Subjects and MethodsSixty Malay native adults with normal or near normal hearing comprising of 20 young adults (21 to 39 years old), 20 middle aged (40 to 59 years old) and 20 older adults (60 to 74 years old) participated in this study. Their speech perception ability was measured using the Malay Hearing in Noise Test (HINT) in four test conditions; 1) in quiet (HINT Q), 2) with noise from front (HINT NF), 3) with noise from right (HINT NR), and 4) with noise from left (HINT NL). Reception thresholds for sentences (RTSs) were measured in each of the aforementioned conditions using an adaptive method.ResultsThe results showed that, 1) genuine age-related decline was found in speech perception performance in HINT (NF), 2) hearing threshold was a major determinant differentiating speech perception performance for HINT (Q) and HINT (NL) conditions, and 3) speech perception performance for HINT (NR) was determined by both age and hearing threshold.ConclusionsThis study suggests that, in older adults, while hearing thresholds affect speech perception in quiet, other factors such as central auditory processing and cognitive functions might be more important determinant factors for speech perception performance in noise.

Screening of cognitive function and hearing impairment in older adults: a preliminary study.

Background. Previous research has found that hearing loss is associated with poorer cognitive function. The question is that when a hearing impairment is being compensated for by appropriately fitted monaural hearing aids, special precautions are still needed when screening cognitive function in older adults. Objective. This research examined cognitive function in elderly hearing aid users who used monaural hearing aids and whether the presence of a hearing impairment should be accounted for when screening cognitive function in these individuals. Methods. Auditory thresholds, sentence reception thresholds, and self-reported outcomes with hearing aids were measured in 34 older hearing aid users to ensure hearing aids were appropriately fitted. Mini-Mental State Examination (MMSE) results obtained in these participants were then compared to normative data obtained in a general older population exhibiting similar demographic characteristics. Stepwise multiple regression analyses were used to examine the effects of demographic and auditory variables on MMSE scores. Conclusions. Results showed that, even with appropriately fitted hearing aids, cognitive decline was significant. Besides the factors commonly measured in the literature, we believed that auditory deprivation was not being fully compensated for by hearing aids. Most importantly, screening of cognitive function should take into account the effects of hearing impairment, even when hearing devices have been appropriately fitted.

Predicting the speech reception thresholds with physical metrics

Many measures [e.g., speech transmission index (STI) and speech intelligibility index (SII)] have been proposed to predict the speech intelligibility in noise. Nevertheless, most of these studies were performed under the conditions with a limited number of maskers. The present study further investigated how well the present speech intelligibility and quality metrics predicted the speech reception thresholds (SRTs) for sentences corrupted by stationary and fluctuating maskers. The SRT scores were collected from 30 normal-hearing (NH) and 15 hearing-impaired (HI) native-Cantonese listeners. Sentences were corrupted by nine types of maskers, including speech-shaped noise and eight real-life environmental noises (4- and 6-talker babbles, upper and lower deck in bus, cafe, Chinese restaurant, MTR carriage, and street). The resulting average SRT scores were subject to the correlation analysis with various metrics computed from the noise-masked sentences. Of all the objective metrics considered, the STI and CSII measures performed the best, and their high correlations (i.e., r = 0.91 to 0.96) were maintained in both NH and HI conditions. This suggests that some of the physical metrics that have been found previously to correlate highly with the intelligibility of sentences in noise may also be used to predict the SRTs affected by different maskers.

Contralateral Suppression of Transient Otoacoustic Emissions and Sentence Recognition in Noise in Young Adults

One purported role of the medial olivocochlear (MOC) efferent system is to reduce the effects of masking noise. MOC system functioning can be evaluated noninvasively in humans through contralateral suppression of otoacoustic emissions. It has been suggested that the strength of the MOC efferent activity should be positively associated with listening performance in noise. The objective of the study was to further explore this notion by examining contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) and sentence recognition in two noises with normal hearing young adults. A repeated measures multivariate quasi-experimental design was employed. Thirty-two normal hearing young adult females participated. Reception thresholds for sentences (RTSs) were determined monaurally and binaurally in quiet and in competing continuous and interrupted noises. Both noises had an identical power spectrum and differed only in their temporal continuity. "Release from masking" was computed by subtracting RTS signal-to-noise ratios in interrupted from continuous noise. TEOAEs were evoked with 80 dB peSPL click stimuli. To examine contralateral suppression, TEOAEs were evaluated with 60 dB peSPL click stimuli with and without a contralateral 65 dB SPL white noise suppressor. A binaural advantage was observed for RTSs in quiet and noise (p < .0001) while there was no difference between ears (p >.05). In noise, performance was superior in the interrupted noise (i.e., RTSs were lower vs. continuous noise; p < .0001). There were no statistically significant differences in TEOAE levels between ears (p >.05). There was also no significant difference in the amount of suppression between ears (p = .41). There were no significant correlations or predictive linear relations between the amount of TEOAE suppression and any indices of sentence recognition in noise (i.e., RTS signal-to-noise ratios and release from masking; p > .05). The findings are not consistent with the notion that increased medial olivocochlear efferent feedback, as assessed via contralateral suppression of TEOAEs, is associated with improved speech perception in continuous and interrupted noise.