Speech Perception Difficulties Research Articles

Peripheral and central contribution to the difficulty of speech in noise perception in dyslexic children.

Noise typically induces both peripheral and central masking of an auditory target. Whereas the idea that a deficit of speech in noise perception is inherent to dyslexia is still debated, most studies have actually focused on the peripheral contribution to the dyslexics' difficulties of perceiving speech in noise. Here, we investigated the respective contribution of both peripheral and central noise in three groups of children: dyslexic, chronological age matched controls (CA), and reading-level matched controls (RL). In all noise conditions, dyslexics displayed significantly lower performance than CA controls. However, they performed similarly or even better than RL controls. Scrutinizing individual profiles failed to reveal a strong consistency in the speech perception difficulties experienced across all noise conditions, or across noise conditions and reading-related performances. Taken together, our results thus suggest that both peripheral and central interference contribute to the poorer speech in noise perception of dyslexic children, but that this difficulty is not a core deficit inherent to dyslexia.

Masked speech perception across the adult lifespan: Impact of age and hearing impairment

As people grow older, speech perception difficulties become highly prevalent, especially in noisy listening situations. Moreover, it is assumed that speech intelligibility is more affected in the event of background noises that induce a higher cognitive load, i.e., noises that result in informational versus energetic masking. There is ample evidence showing that speech perception problems in aging persons are partly due to hearing impairment and partly due to age-related declines in cognition and suprathreshold auditory processing. In order to develop effective rehabilitation strategies, it is indispensable to know how these different degrading factors act upon speech perception. This implies disentangling effects of hearing impairment versus age and examining the interplay between both factors in different background noises of everyday settings. To that end, we investigated open-set sentence identification in six participant groups: a young (20–30 years), middle-aged (50–60 years), and older cohort (70–80 years), each including persons who had normal audiometric thresholds up to at least 4 kHz, on the one hand, and persons who were diagnosed with elevated audiometric thresholds, on the other hand. All participants were screened for (mild) cognitive impairment. We applied stationary and amplitude modulated speech-weighted noise, which are two types of energetic maskers, and unintelligible speech, which causes informational masking in addition to energetic masking. By means of these different background noises, we could look into speech perception performance in listening situations with a low and high cognitive load, respectively. Our results indicate that, even when audiometric thresholds are within normal limits up to 4 kHz, irrespective of threshold elevations at higher frequencies, and there is no indication of even mild cognitive impairment, masked speech perception declines by middle age and decreases further on to older age. The impact of hearing impairment is as detrimental for young and middle-aged as it is for older adults. When the background noise becomes cognitively more demanding, there is a larger decline in speech perception, due to age or hearing impairment. Hearing impairment seems to be the main factor underlying speech perception problems in background noises that cause energetic masking. However, in the event of informational masking, which induces a higher cognitive load, age appears to explain a significant part of the communicative impairment as well. We suggest that the degrading effect of age is mediated by deficiencies in temporal processing and central executive functions. This study may contribute to the improvement of auditory rehabilitation programs aiming to prevent aging persons from missing out on conversations, which, in turn, will improve their quality of life.

Is There a Relationship Between Speech Identification in Noise and Categorical Perception in Children With Dyslexia?

Children with dyslexia have been suggested to experience deficits in both categorical perception (CP) and speech identification in noise (SIN) perception. However, results regarding both abilities are inconsistent, and the relationship between them is still unclear. Therefore, this study aimed to investigate the relationship between CP and the psychometric function of SIN perception. Sixteen children with dyslexia, 16 chronological-age controls, and 16 reading-level controls were evaluated in CP of a voicing continuum and in consonant identification in both stationary and fluctuating noises. There was a small but significant impairment in speech identification performance of children with dyslexia in stationary noise compared with chronological age-matched controls (but not reading level-matched controls). However, their performance increased in a fluctuating background, hence suggesting normal masking and unmasking effects and preserved sensory processing of speech information. Regarding CP, location of the phoneme boundary differed in the children with dyslexia compared with both control groups. However, scrutinizing individual profiles failed to reveal consistently poor performance in SIN and CP tasks. In addition, there was no significant correlation between CP, SIN perception, and reading scores in the group with dyslexia. The relationship between the SIN deficit and CP, and how they potentially affect reading in children with dyslexia, remains unclear. However, these results are inconsistent with the notion that children with dyslexia suffer from a low-level temporal processing deficit and rather suggest a role of nonsensory (e.g., attentional) factors in their speech perception difficulties.

Relationship between Speech Production and Perception in People Who Stutter.

Speech production difficulties are apparent in people who stutter (PWS). PWS also have difficulties in speech perception compared to controls. It is unclear whether the speech perception difficulties in PWS are independent of, or related to, their speech production difficulties. To investigate this issue, functional MRI data were collected on 13 PWS and 13 controls whilst the participants performed a speech production task and a speech perception task. PWS performed poorer than controls in the perception task and the poorer performance was associated with a functional activity difference in the left anterior insula (part of the speech motor area) compared to controls. PWS also showed a functional activity difference in this and the surrounding area [left inferior frontal cortex (IFC)/anterior insula] in the production task compared to controls. Conjunction analysis showed that the functional activity differences between PWS and controls in the left IFC/anterior insula coincided across the perception and production tasks. Furthermore, Granger Causality Analysis on the resting-state fMRI data of the participants showed that the causal connection from the left IFC/anterior insula to an area in the left primary auditory cortex (Heschl’s gyrus) differed significantly between PWS and controls. The strength of this connection correlated significantly with performance in the perception task. These results suggest that speech perception difficulties in PWS are associated with anomalous functional activity in the speech motor area, and the altered functional connectivity from this area to the auditory area plays a role in the speech perception difficulties of PWS.

Production and perception of clear speech

When talkers are aware of listeners’ speech perception difficulties due to hearing loss, noise, or a language barrier, they typically adopt an intelligibility-enhancing speaking style known as “clear speech.” To the extent that clear speech is more intelligible than “conversational speech,” a cross-style acoustic-phonetic comparison provides information about factors that affect speech intelligibility. I will present data from a project that tested the hypothesis that clear speech is guided by both universal, auditory-perceptual factors and language-specific, structural factors. The former serve to enhance the overall acoustic salience of the speech signal such that it is more resistant to the adverse effects of noise or listener-related perceptual deficits; the latter serves to enhance the realization of phonological contrasts. This hypothesis predicts that clear speech production shows predictable and systematic cross-language similarities and differences, and that the clear speech intelligibility benefit is modulated by the listeners’ experience with the target language. To address these predictions, we present data from a cross-language comparison of clear speech production and a cross-population comparison of clear speech perception. These studies provide fundamental information about variability in speech intelligibility which may ultimately lead to effective, efficient, and listener-specific speech intelligibility enhancement strategies.

Investigating the role of supra-threshold auditory processing and cognitive abilities in presbyacusis

Anecdotal evidence and experimental investigations indicate that older people experience increased speech-perception difficulties, especially in noisy environments. Since peripheral hearing sensitivity declines with age, lower speech intelligibility can often be explained by a reduction in audibility. However, aided speech-perception in hearing-impaired listeners frequently falls short of the performance level that would be expected based on the audibility of the speech signal. Given that many of these listeners are older, poor performance may be partly caused by age-related changes in supra-threshold auditory and/or cognitive processes that are not captured by an audiometric assessment. The presentation will discuss experimental evidence obtained from clinically normal-hearing adult listeners showing that auditory temporal processing, cognition, and speech-in-noise perception are indeed linked and, independently of hearing loss, decline across the adult lifespan. These findings highlight the need to take...

Effect of musical training on masking paradigm

Background: Musicians outperform nonmusicians on brainstem and cortical level processing. However, there are limited literature comparing musicians and nonmusicians on the overall release of masking abilities and correlation across otoacoustic emissions (OAEs), masking level difference (MLD) and quick speech-in-noise (Quick-SIN). Aim: To investigate the physiological differences between musicians and nonmusicians by evaluating the effect of musical training on contralateral suppression (CAS) of OAE, MLD, and Quick-SIN. Materials and Methods: Distortion product OAEs (DPOAEs) recording with and without noise, MLD test using continuous (CMLD) and pulsating pure tones (PMLD) and Quick-SIN in Kannada were carried out on 15 musicians and 15 nonmusicians. Results: Musicians outperformed nonmusicians on Quick-SIN and CAS of OAEs. However, no significant difference was observed between two groups on CMLD and PMLD. There was a significant difference observed in CMLD, PMLD as well as suppression amplitude across frequencies tested in both groups. A significant difference between PMLD and CMLD was observed only for musicians at 2 kHz. In both groups, there was a significant level of correlation for CAS of DPOAE and Quick-SIN with CMLD and with PMLD between the parameters tested. Conclusion: The results of our finding suggest that CAS of DPOAE and Quick-SIN are sensitive tools to quantify the effect of musical training, compared to MLD. Musical training helps to strengthen afferent and efferent pathways, and hence it aids in speech perception abilities in noise. Hence, for the intervention of individuals with difficulties in speech perception in noise, musical training can be a choice to be considered. As well for appropriate diagnosis and interpretation, one needs to consider the musical experience of individual tested.

Mutations in apoptosis-inducing factor cause X-linked recessive auditory neuropathy spectrum disorder

BackgroundAuditory neuropathy spectrum disorder (ANSD) is a form of hearing loss in which auditory signal transmission from the inner ear to the auditory nerve and brain stem is distorted, giving...

Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users.

Past work has shown that low-rate frequency modulation (FM) may help preserve signal coherence, aid segmentation at word and syllable boundaries, and benefit speech intelligibility in the presence of a masker. This study evaluated whether difficulties in speech perception by cochlear implant (CI) users relate to a deficit in the ability to discriminate among stochastic low-rate patterns of FM. This is a correlational study assessing the association between the ability to discriminate stochastic patterns of low-rate FM and the intelligibility of speech in noise. Thirteen postlingually deafened adult CI users participated in this study. Using modulators derived from 5-Hz lowpass noise applied to a 1-kHz carrier, thresholds were measured in terms of frequency excursion both in quiet and with a speech-babble masker present, stimulus duration, and signal-to-noise ratio in the presence of a speech-babble masker. Speech perception ability was assessed in the presence of the same speech-babble masker. Relationships were evaluated with Pearson product-moment correlation analysis with correction for family-wise error, and commonality analysis to determine the unique and common contributions across psychoacoustic variables to the association with speech ability. Significant correlations were obtained between masked speech intelligibility and three metrics of FM discrimination involving either signal-to-noise ratio or stimulus duration, with shared variance among the three measures accounting for much of the effect. Compared to past results from young normal-hearing adults and older adults with either normal hearing or a mild-to-moderate hearing loss, mean FM discrimination thresholds obtained from CI users were higher in all conditions. The ability to process the pattern of frequency excursions of stochastic FM may, in part, have a common basis with speech perception in noise. Discrimination of differences in the temporally distributed place coding of the stimulus could serve as this common basis for CI users.

Enhanced segregation of concurrent sounds with similar spectral uncertainties in individuals with autism spectrum disorder.

When acoustic signals from different sound sources are mixed upon arrival at the ears, the auditory system organizes these acoustic elements by their features. This study shows that individuals with autism spectrum disorder (ASD) performed better in terms of hearing a target sequence among distractors that had similar spectral uncertainties. Their superior performance in this task indicates an enhanced discrimination between auditory streams with the same spectral uncertainties but different spectro-temporal details. The enhanced discrimination of acoustic components may be related to the absence of the automatic grouping of acoustic components with the same features, which results in difficulties in speech perception in a noisy environment. On the other hand, the ASD group and the control group had similar performance in hearing a target sequence among distractors that had different spatial cues defined by interaural intensity differences.

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.

The impact of cochlear implantation on cognition in older adults: a systematic review of clinical evidence.

BackgroundHearing loss is the third most prevalent chronic condition faced by older adults and has been linked to difficulties in speech perception, activities of daily living, and social interaction. Recent studies have suggested a correlation between severity of hearing loss and an individual’s cognitive function; however, a causative link has yet to be established. One intervention option for management of the most severe to profound hearing loss in older adults is cochlear implantation. We performed a review to determine the status of the literature on the potential influence of cochlear implantation on cognition in the older adult population.MethodsOver 3800 articles related to cochlear implants, cognition, and older adults were reviewed. Inclusion criteria were as follows: (1) study population including adults > 65 years, (2) intervention with cochlear implantation, and (3) cognition as the primary outcome measure of implantation.ResultsOut of 3,886 studies selected, 3 met inclusion criteria for the review.ConclusionsWhile many publications have shown that cochlear implants improve speech perception, social functioning, and overall quality of life, we found no studies in the English literature that have prospectively evaluated changes in cognitive function after implantation with modern cochlear implants in older adults. The state of the current literature reveals a need for further clinical research on the impact of cochlear implantation on cognition in older adults.

Речь и коммуникация при расстройствах аутистического спектра

The present article is a review of English_language literature on the topic of development of language and communication in people with autism spectrum disorders (ASD). It is shown that language in ASD often differs from the one in typical development, particularly in terms of pragmatics, unusual intonation and echolalia, and difficulties in speech perception and comprehension may also be present. Nevertheless, it should be noted that the results of many studies in this area are controversial due to a variety of reasons and it is hardly possible to reach agreement on many questions in this area.

ERP correlates of auditory goal-directed behavior of younger and older adults in a dynamic speech perception task

The ability to understand speech under adverse listening conditions deteriorates with age. In addition to genuine hearing deficits, age-related declines in attentional and inhibitory control are assumed to contribute to these difficulties. Here, the impact of task-irrelevant distractors on speech perception was studied in 28 younger and 24 older participants in a simulated “cocktail party” scenario. In a two-alternative forced-choice word discrimination task, the participants responded to a rapid succession of short speech stimuli (“on” and “off”) that was presented at a frequent standard location or at a rare deviant location in silence or with a concurrent distractor speaker. Behavioral responses and event-related potentials (mismatch negativity MMN, P3a, and reorienting negativity RON) were analyzed to study the interplay of distraction, orientation, and refocusing in the presence of changes in target location. While shifts in target location decreased performance of both age groups, this effect was more pronounced in the older group. Especially in the distractor condition, the electrophysiological measures indicated a delayed attention capture and a delayed re-focussing of attention toward the task-relevant stimulus feature in the older group, relative to the young group. In sum, the results suggest that a delay in the attention switching mechanism contribute to the age-related difficulties in speech perception in dynamic listening situations with multiple speakers.

Audiovisual integration in children listening to spectrally degraded speech.

The study explored whether visual information improves speech identification in typically developing children with normal hearing when the auditory signal is spectrally degraded. Children (n=69) and adults (n=15) were presented with noise-vocoded sentences from the Children's Co-ordinate Response Measure (Rosen, 2011) in auditory-only or audiovisual conditions. The number of bands was adaptively varied to modulate the degradation of the auditory signal, with the number of bands required for approximately 79% correct identification calculated as the threshold. The youngest children (4- to 5-year-olds) did not benefit from accompanying visual information, in comparison to 6- to 11-year-old children and adults. Audiovisual gain also increased with age in the child sample. The current data suggest that children younger than 6 years of age do not fully utilize visual speech cues to enhance speech perception when the auditory signal is degraded. This evidence not only has implications for understanding the development of speech perception skills in children with normal hearing but may also inform the development of new treatment and intervention strategies that aim to remediate speech perception difficulties in pediatric cochlear implant users.

Event-related potentials for better speech perception in noise by cochlear implant users

Speech perception in noise is still difficult for cochlear implant (CI) users even with many years of CI use. This study aimed to investigate neurophysiological and behavioral foundations for CI-dependent speech perception in noise. Seventeen post-lingual CI users and twelve age-matched normal hearing adults participated in two experiments. In Experiment 1, CI users' auditory-only word perception in noise (white noise, two-talker babble; at 10 dB SNR) degraded by about 15%, compared to that in quiet (48% accuracy). CI users' auditory-visual word perception was generally better than auditory-only perception. Auditory-visual word perception was degraded under information masking by the two-talker noise (69% accuracy), compared to that in quiet (77%). Such degradation was not observed for white noise (77%), suggesting that the overcoming of information masking is an important issue for CI users' speech perception improvement. In Experiment 2, event-related cortical potentials were recorded in an auditory oddball task in quiet and noise (white noise only). Similarly to the normal hearing participants, the CI users showed the mismatch negative response (MNR) to deviant speech in quiet, indicating automatic speech detection. In noise, the MNR disappeared in the CI users, and only the good CI performers (above 66% accuracy) showed P300 (P3) like the normal hearing participants. P3 amplitude in the CI users was positively correlated with speech perception scores. These results suggest that CI users’ difficulty in speech perception in noise is associated with the lack of automatic speech detection indicated by the MNR. Successful performance in noise may begin with attended auditory processing indicated by P3.

Functional correlates of the speech-in-noise perception impairment in dyslexia: An MRI study

Dyslexia is a language-based neurodevelopmental disorder. It is characterized as a persistent deficit in reading and spelling. These difficulties have been shown to result from an underlying impairment of the phonological component of language, possibly also affecting speech perception. Although there is little evidence for such a deficit under optimal, quiet listening conditions, speech perception difficulties in adults with dyslexia are often reported under more challenging conditions, such as when speech is masked by noise. Previous studies have shown that these difficulties are more pronounced when the background noise is speech and when little spatial information is available to facilitate differentiation between target and background sound sources. In this study, we investigated the neuroimaging correlates of speech-in-speech perception in typical readers and participants with dyslexia, focusing on the effects of different listening configurations. Fourteen adults with dyslexia and 14 matched typical readers performed a subjective intelligibility rating test with single words presented against concurrent speech during functional magnetic resonance imaging (fMRI) scanning. Target words were always presented with a four-talker background in one of three listening configurations: Dichotic, Binaural or Monaural. The results showed that in the Monaural configuration, in which no spatial information was available and energetic masking was maximal, intelligibility was severely decreased in all participants, and this effect was particularly strong in participants with dyslexia. Functional imaging revealed that in this configuration, participants partially compensate for their poorer listening abilities by recruiting several areas in the cerebral networks engaged in speech perception. In the Binaural configuration, participants with dyslexia achieved the same performance level as typical readers, suggesting that they were able to use spatial information when available. This result was, however, associated with increased activation in the right superior temporal gyrus, suggesting the need to reallocate neural resources to overcome speech-in-speech difficulties. Taken together, these results provide further understanding of the speech-in-speech perception deficit observed in dyslexia.

Acceptable noise level in bilinguals: Consideration of signal and masker effects

This study explores how bilingual listeners’ acceptable noise level (ANL) may be affected by the language of the signal, language of the masker, and talkers in the masker. ANL measures how much a listener tolerates background noise while listening to running speech. It differs from conventional speech recognition tasks in that it does not concern one’s ability to comprehend speech. Hence, ANLs are expected to be relatively free of bilingual background. In this study, the signal (running passages from New York State Department of Motor Vehicles driving manual) was presented in two languages (English versus Spanish). The maskers (Auditec babbles) were manipulated in language (English versus Spanish) and number of talkers (four versus twelve). Additionally, three groups of 12 listeners participated in the study—monolingual English, Spanish-English bilingual, and Russian-English bilingual. A 3×2×2×2 mixed, repeated design was carried out with listener group as the between-subjects factor, and signal and masker language and number factors as the within-subjects factors. Preliminary findings reveal a non-significant effect for all four factors; however, a marginally significant four-way interaction (p = 0.048) invites group wise analysis. Results may help establish new clinical approaches in assessing listeners’ speech perception difficulty in noise, regardless of language background.

The neurobiology of speech perception decline in aging

Speech perception difficulties are common among elderlies; yet the underlying neural mechanisms are still poorly understood. New empirical evidence suggesting that brain senescence may be an important contributor to these difficulties has challenged the traditional view that peripheral hearing loss was the main factor in the etiology of these difficulties. Here, we investigated the relationship between structural and functional brain senescence and speech perception skills in aging. Following audiometric evaluations, participants underwent MRI while performing a speech perception task at different intelligibility levels. As expected, with age speech perception declined, even after controlling for hearing sensitivity using an audiological measure (pure tone averages), and a bioacoustical measure (DPOAEs recordings). Our results reveal that the core speech network, centered on the supratemporal cortex and ventral motor areas bilaterally, decreased in spatial extent in older adults. Importantly, our results also show that speech skills in aging are affected by changes in cortical thickness and in brain functioning. Age-independent intelligibility effects were found in several motor and premotor areas, including the left ventral premotor cortex and the right supplementary motor area (SMA). Age-dependent intelligibility effects were also found, mainly in sensorimotor cortical areas, and in the left dorsal anterior insula. In this region, changes in BOLD signal modulated the relationship between age and speech perception skills suggesting a role for this region in maintaining speech perception in older ages. These results provide important new insights into the neurobiology of speech perception in aging.

Elaboración de una versión reducida de las listas de frases en español (vr-LFE) para evaluar la percepción del habla con ruido

This article presents, a short version of the ‘listas de frases en español’ (vr-LFE; “Lists of Phrases in Spanish”) to evaluate speech perception in noise. The original version is an adaptation of the SPIN (Speech Perception in Noise) test for the English language. The original LFE consists of 6 lists, each of them including 25 high-predictability sentences and 25 low-predictability sentences. The difference between the correct recognition scores on the two types of sentences provides an estimation of the effective use of linguistic context (semantic, syntactic, and pragmatic information) by the listener in the speech perception process. In the present work, 60 sentences were selected from an initial pool of 300 sentences. These 60 sentences were arranged in 5 lists of 12 sentences each (6 high-predictability and 6 low-predictability sentences). This version preserves the same characteristics of reliability (equivalence among the lists) and validity (sensibility to the effects of sentence context and to the signal-to-noise ratio) as the original version, but considerably reduces the time needed for its administration. These lists can be used to evaluate speech perception difficulties in noise in older listeners with mild-to-moderate hearing loss (presbycusis), with or without mild cognitive impairment, and in non-native listeners with different degrees of linguistic competence.