Hearing Speech Research Articles

Acoustic Source Localization and Deconvolution-Based Separation

This paper examines two fundamental issues in sound field analysis: acoustic sources localization and separation. Algorithms are developed to locate and separate acoustic signals on the basis of plane-wave decomposition. In the localization stage, directions of plane waves are determined using either minimum variance distortionless response (MVDR) method or multiple signal classification (MUSIC) method. For broadband scenarios, coherent and incoherent techniques are utilized in the localization procedure. In the separation stage, two approaches with overdetermined and underdetermined settings can be employed. In the overdetermined approach, Tikhonov regularization (TIKR) is utilized to recover the source signals. In the underdetermined approach, the steering matrix is augmented by including the directions that have been determined in the localization stage. Hence, the separation problem is formulated into a compressive sensing (CS) problem which can be effectively solved by using convex (CVX) optimization. Simulation and experiments are conducted for a 24-element circular array. Objective tests using perceptual evaluation of speech quality (PESQ) tests and subjective listening tests demonstrate that the proposed methods yield speech signals with well separated and improved quality, as compared to the mixed signals.

The Developmental Coordination Disorder Questionnaire—German Version—in a Pediatric Outpatient Clinic for Communication Disorders

Aims: Children with speech disorder, hearing loss, or ASS often show comorbidity in motoric skills. Can parents identify and describe it with the DCDQ-G correctly? Methods: The DCDQ-G is a screening questionnaire for parents to detect developmental coordination disorders. The results of the questionnaire were compared with the neuromotoric skills made by a pediatrician or child neurologist. Parents of 119 children, aged 5.0 to 7.11 years completed the DCDQ-G. Most of the children presented speech disorders, hearing loss, or ASS. Results: We screened 119 children. Data from 92 were complete, including 22 children with migrational background (23.9%). Overall, 15 incomplete data sets were from parents with migrational background (55%). The average age was 5.10 years, including 78 boys (65.5%) and 52 girls (34.5%). The results were compared with the original data from Canada (Wilson et al 2009) and the results from the German study (Kennedy-Behr et al 2013). The specify and sensitivity in our whole group and in the study group are comparable to the results of the Canadian and German study populations. The prevalence of how parents correctly judge the motoric skills of their children is also comparable. Conclusion: The DCDQ-G is quite a useful screening instrument for parents to judge the neuromotoric development of their children in a pediatric outpatient clinic for communication disorders. The results are similar to the original study from Canada and the evaluation of the German DCDQ version in Germany. The results show some of the questions (Question 8 and 9) seem to be difficult for parents of preschool children to answer. Keywords: developmental coordination disorder.

Need of speech-in-noise testing to assess listening difficulties in older adults

Objective: To assess the need of including speech-in-noise tests in the audiological test battery in older adults and the key factors that affect performance in these tests. Older adults complain significantly more than other age groups regarding difficulties in hearing speech in noise, even in the presence of a normal audiogram. Hearing speech in noise is a very complex function underpinned by high-level, cognitive and analytic processing along with low-level sensory processing. Study design: The design reflected an overview of the effect of aging in the auditory system and the acoustic and cognitive resources required for hearing speech in noise. In addition, a review of key clinical studies of speech-in-noise tests was conducted in older adults. Results: Age affects the peripheral and central auditory system but also the entire brain at a structural, functional and neurochemical level. Listening to speech in noise requires complex and multimodal processing in auditory, linguistic, cognitive and other domains via multiple brain interconnections that are not yet fully understood. There are several different theories and models proposed to explain age related declines in speech-in-noise performance. Listeners may give different scores in speech-in-noise tests depending on the parameters of these tests, e.g. type of speech stimulus (words vs. sentences) and masker (noise, multi-talker babbler). Speech recognition in noise depends on the degree of direct interaction of the target and masker at the cochlear level (energetic masking) and on how well speech can be dissociated from the masker (informational masking). Studies show more pronounced effects of informational masking and of lexical interference in older adults, who also show poorer use of auditory sensory type cues, and require greater listening effort in order to perform speech-in-noise tasks. Conclusion: Assessing older adults with pure tone audiometry only and addressing these difficulties with hearing amplification may not be enough to address older adults’ hearing needs, as this approach does not take into account the higher level impairments contributing to hearing and listening problems. Careful audiological assessment with appropriately chosen speech-in-noise tests, together with audiometry and potentially additional tests, are thus required in order to identify and characterize hearing difficulties in older adults, in order to inform their management plan.

Relation between measures of psychoacoustic abilities and masking release for unprocessed, envelope, and temporal fine-structure speech in listeners with normal and impaired hearing

Léger et al. [J. Acoust. Soc. Am. 135, 2160, 2014] studied masking release in normal-hearing and hearing-impaired listeners using unprocessed speech and speech processed to convey envelope (ENV) or temporal fine-structure (TFS) cues. Consonant identification scores in speech-shaped background noise (continuous and square-wave interrupted at a rate of 10 Hz) indicated a substantial masking release (MR, better performance in the interrupted noise) for all speech types for normal-hearing listeners but only for the TFS speech in most hearing-impaired listeners. The current study was concerned with relating consonant identification scores and masking release to SRTs for sentences in both types of noise as well as to measurements of basic psychoacoustic abilities. These measures included absolute pure-tone detection thresholds, estimates of auditory bandwidth using a notched-noise procedure, and estimates of cochlear compression obtained using a forward-masking paradigm. For both unprocessed and ENV speech, intelligibility scores and MR were correlated with absolute thresholds and auditory bandwidths in the mid-frequency region (but not at a lower frequency). These correlations were less strong for TFS speech intelligibility and did not predict MR. Cochlear compression was not related to speech intelligibility when controlling for the effect of absolute thresholds. [Work supported by NIH R01 DC000117.]

Using speech intelligibility metrics to predict the performance of hearing-impaired listeners

When fitting a hearing aid to a hearing-impaired listener, it would be very beneficial for an audiologist to be able to use an objective metric to determine the best signal processing algorithm to compensate for the user’s loss and improve the user’s understanding of speech in degraded acoustic environments. Several metrics have been considered to predict impaired listeners’ speech recognition, including modified versions of the Speech Intelligibility Index (SII) [e.g., Ricketts, Ear Hear. 17, 124–132 (1996)] and the Speech Transmission Index (STI) [e.g., Humes et al., J. Speech Hear. Res. 29, 447–462 (1986)]. For impaired listeners using linear amplification hearing aids, there are metrics that work fairly well. For listeners using hearing aids that include nonlinear processing, such as amplitude compression, results have not been as successful. This talk will review the current status of metric capabilities, approaches that have been proposed to mitigate metric limitations and which metric features appe...

Factors that increase processing demands when listening to speech

Listening effort is an increasingly important concept for applied hearing researchers, but it has not been well elaborated in the cognitive literature. We propose that listening effort is the product of two factors: the processing demands imposed by the listening situation, and the cognitive resources that an individual brings to bear, to compensate for demands. Whereas cognitive resources differ markedly among individuals, processing demands are generally constant in a given listening situation, at least for normal-hearing individuals, and fall into at least three different categories: (i) perceptual demands, (ii) linguistic demands, and (iii) concurrent task demands. Perceptual demands are increased when the speech is degraded, when concurrent interfering sounds are present, or when the listener is hearing impaired. Linguistic demands are increased, for example, when speech is semantically or syntactically complex, or when meaning is ambiguous. Finally, when a listener is performing another task (such as driving) while hearing speech, additional demands are present. A series of behavioral and neuroimaging experiments reveals the nature of these different demands, which appear to be largely independent but to interact in left inferior frontal cortex; fMRI activity in this area may serve as an objective, quantifiable, measure of listening effort. Interactions among different types of demand imply that they cannot be fully understood by studying them in isolation.

Conducting Neuroscience to Guide the Development of AI

Study of the human brain through fMRI can potentially benefit the pursuit of artificial intelligence. Four examples are presented. First, fMRI decoding of the brain activity of subjects watching video clips yields higher accuracy than state-of-the-art computer-vision approaches to activity recognition. Second, novel methods are presented that decode aggregate representations of complex visual stimuli by decoding their independent constituents. Third, cross-modal studies demonstrate the ability to decode the brain activity induced in subjects watching video stimuli when trained on the brain activity induced in subjects seeing text or hearing speech stimuli and vice versa. Fourth, the time course of brain processing while watching video stimuli is probed with scanning that trades off the amount of the brain scanned for the frequency at which it is scanned. Techniques like these can be used to study how the human brain grounds language in visual perception and may motivate development of novel approaches in AI.

Emergence of biological markers of musicianship with school-based music instruction.

Musician children and adults demonstrate biological distinctions in auditory processing relative to nonmusicians. For example, musician children and adults have more robust neural encoding of speech harmonics, more adaptive sound processing, and more precise neural encoding of acoustically similar sounds; these enhancements may contribute to musicians' linguistic advantages, such as for hearing speech in noise and reading. Such findings have inspired proposals that the auditory and cognitive stimulation induced by musical practice renders musicians enhanced according to biological metrics germane to communication. Cross-sectional methodologies comparing musicians with nonmusicians, however, are limited by the inability to disentangle training-related effects from demographic and innate qualities that may predistinguish musicians. Over the past several years, our laboratory has addressed this problem by examining the emergence of neural markers of musicianship in children and adolescents using longitudinal approaches to track the development of biological indices of speech processing. This work was conducted in partnership with successful community-based music programs, thus avoiding reliance on a synthetic program for the purposes of laboratory study. Outcomes indicate that many of musicians' auditory-related biological enhancements emerge with training and may promote the acquisition of language skills, including in at-risk populations.

The just-noticeable difference in speech-to-noise ratio.

Just-noticeable differences (JNDs) have been measured for various features of sounds, but despite its importance to communication, there is no benchmark for what is a just-noticeable—and possibly meaningful—difference in speech-to-noise ratio (SNR). SNR plays a crucial role in speech communication for normal-hearing and hearing-impaired listeners. Difficulty hearing speech in background noise—a poor SNR—often leads to dissatisfaction with hearing-assistance devices. While such devices attempt through various strategies to address this problem, it is not currently known how much improvement in SNR is needed to provide a noticeable benefit. To investigate what is a noticeable benefit, we measured the JND in SNR for both normal-hearing and hearing-impaired listeners. Here, we report the SNR JNDs of 69 participants of varying hearing ability, estimated using either an adaptive or fixed-level procedure. The task was to judge which of the two intervals containing a sentence in speech-spectrum noise presented over headphones was clearer. The level of each interval was roved to reduce the influence of absolute level cues. The results of both procedures showed an average SNR JND of 3 dB that was independent of hearing ability. Further experiments using a subset of normal-hearing listeners showed that level roving does elevate threshold. These results suggest that noise reduction schemes may need to achieve a benefit greater than 3 dB to be reliably discriminable.

Hearing aid and hearing assistance technology use in Aotearoa/New Zealand

Objective: The purpose of this study was to describe factors that are related to hearing aid and hearing assistance technology ownership and use in Aotearoa/New Zealand. Design: Adults with hearing impairment living in New Zealand were surveyed regarding health-related quality of life and device usage. Audiometric data (hearing sensitivity and speech in noise) were collected. Study sample: Data were obtained from 123 adults with hearing impairment: 73 reported current hearing-aid use, 81 reported current hearing assistance technology use. Results: In both analyses, device users had more difficulty understanding speech in background noise, had poor hearing in both their better and worse hearing ears, and perceived more consequences of hearing impairment in their everyday lives (both emotionally and socially) than non-hearing-aid users. Discriminant analyses showed that the social consequences of hearing impairment and the better ear hearing best classified hearing aid users from non-users but social consequences and worse ear hearing best classified hearing assistance technology users from non-users. Conclusions: Quality of life measurements and speech-in-noise assessments provide useful clinical information. Hearing-impaired adults in New Zealand who use hearing aids also tend to use hearing assistance technology, which has important clinical implications.

Musical training orchestrates coordinated neuroplasticity in auditory brainstem and cortex to counteract age-related declines in categorical vowel perception.

Musicianship in early life is associated with pervasive changes in brain function and enhanced speech-language skills. Whether these neuroplastic benefits extend to older individuals more susceptible to cognitive decline, and for whom plasticity is weaker, has yet to be established. Here, we show that musical training offsets declines in auditory brain processing that accompanying normal aging in humans, preserving robust speech recognition late into life. We recorded both brainstem and cortical neuroelectric responses in older adults with and without modest musical training as they classified speech sounds along an acoustic-phonetic continuum. Results reveal higher temporal precision in speech-evoked responses at multiple levels of the auditory system in older musicians who were also better at differentiating phonetic categories. Older musicians also showed a closer correspondence between neural activity and perceptual performance. This suggests that musicianship strengthens brain-behavior coupling in the aging auditory system. Last, "neurometric" functions derived from unsupervised classification of neural activity established that early cortical responses could accurately predict listeners' psychometric speech identification and, more critically, that neurometric profiles were organized more categorically in older musicians. We propose that musicianship offsets age-related declines in speech listening by refining the hierarchical interplay between subcortical/cortical auditory brain representations, allowing more behaviorally relevant information carried within the neural code, and supplying more faithful templates to the brain mechanisms subserving phonetic computations. Our findings imply that robust neuroplasticity conferred by musical training is not restricted by age and may serve as an effective means to bolster speech listening skills that decline across the lifespan.

Audiological profile in cases with cerebrovascular accidents

Background: Over the past decades there has been increase demand of audiological complaints coinciding with neurological impairments due to cerebrovascular accidents (CVAs). Most of the cases represent inconsistent responses to acoustic stimuli or total lack of response to sound, documented as auditory agnosia. Aim: The present investigation aims at understanding of potential anatomical co-relates to the involvement of the cortical structure and the processing of auditory stimuli. Materials and Methods: A case series with convenient sampling method included eight cases (six male and two female) with age range 45-55 years with CVA, were taken for this study. Of them two cases were found with lesion in right middle cerebral artery, four cases with left middle cerebral artery and two cases with left posterior cerebral artery lesion confirmed from magnetic resonance imaging scan. Audiological test battery including otoscopy, tuning fork test, pure tone audiometry, speech audiometry, immittance audiometry, dichotic-diotic listening test, auditory brainstem responses, otoacoustic emissions and gap detection tests were carried out including routine ENT evaluation. Results and Conclusion: Result suggests; there is a significant difference in hearing threshold and speech perception in all the eight subjects. The findings and compromised vascular anatomy in all these cases were discussed in this article.

A Study of Permanent Physical Disability Pattern in Motor Vehicle Accident Cases Presenting at Sms Hospital, Jaipur During the Year 2012–2013 a Prospective Study

Worldwide motor vehicle collisions lead to death and disability as well as financial costs to both society and the individuals involved. The maximum numbers of disabled people as a consequence of motor vehicle collision in our study were in 21-30 years age group (30.3%) followed by 31-40 years (24.6%) and 41-50 years (15.7%). Majority of the disabled people were literates constituting 85.43% of total cases. Majority of the disabled persons in our study were persons engaged in the private sector (49%) and about 20% of the disabilities were found to have occurred in students. Majority of the disabled persons were on motorized two wheelers (66.6%) followed by 22% pedestrians. Among the 350 disabled people, majority of the people suffered locomotor disabilities (88.57%) followed by visual (4%); hearing disability (3.15%) and speech disability (2.28%). The aim of this study to evaluate the level and patterns of disabilities resulting from traffic injuries among the study population as well as its distribution by age, gender and type of motor-vehicle user. Language: en

Pediatric hearing loss.

On the basis of strong research, universal newborn screening should be performed before age 1 month with repeat or follow-up testing for those who do not pass performed before age 3 months and intervention started before age 6 months. On the basis of strong research and consensus statement, tympanostomy tubes should be considered for individuals with bilateral persistent middle ear effusion for 3 months or greater and a documented conductive hearing loss. On the basis of consensus statement, all children with suspected hearing loss should have an age appropriate hearing test. On the basis of strong research, the most common form of congenital hearing loss is genetic. Most of this is nonsyndromic hearing loss.

Auditory processing disorder: Clinical and international perspective

APD may be considered a developmental, hearing or neurological disorder, depending on etiology, but in all cases, it is a listening difficulty without an abnormality of pure tone sensitivity. It has been variously defined as a disorder of the central auditory system associated with impaired spatial hearing, auditory discrimination, temporal processing, and performance with competing or degraded sounds. Clinical testing typically examines perception, intelligibility and ordering of both speech and non-speech sounds. While deficits in higher-order cognitive, communicative, and language functions are excluded in some definitions, recent consensus accepts that these functions may be inseparable from active listening. Some believe that APD in children is predominantly or exclusively cognitive in origin, while others insist that true APD has its origins within the auditory brainstem. However, children or their carers presenting at clinics typically complain of difficulty hearing speech in noise, remembering or understanding instructions, and attending to sounds. APD usually occurs alongside other developmental disorders (e.g., language impairment) and may be indistinguishable from them. Consequently, clinicians are uncertain how to diagnose or manage APD; both test procedures and interventions vary widely, even within a single clinic. Effective remediation primarily consists of improving the listening environment and providing communication devices.

Relation between speech-in-noise threshold, hearing loss and cognition from 40-69 years of age.

BackgroundHealthy hearing depends on sensitive ears and adequate brain processing. Essential aspects of both hearing and cognition decline with advancing age, but it is largely unknown how one influences the other. The current standard measure of hearing, the pure-tone audiogram is not very cognitively demanding and does not predict well the most important yet challenging use of hearing, listening to speech in noisy environments. We analysed data from UK Biobank that asked 40–69 year olds about their hearing, and assessed their ability on tests of speech-in-noise hearing and cognition.Methods and FindingsAbout half a million volunteers were recruited through NHS registers. Respondents completed ‘whole-body’ testing in purpose-designed, community-based test centres across the UK. Objective hearing (spoken digit recognition in noise) and cognitive (reasoning, memory, processing speed) data were analysed using logistic and multiple regression methods. Speech hearing in noise declined exponentially with age for both sexes from about 50 years, differing from previous audiogram data that showed a more linear decline from <40 years for men, and consistently less hearing loss for women. The decline in speech-in-noise hearing was especially dramatic among those with lower cognitive scores. Decreasing cognitive ability and increasing age were both independently associated with decreasing ability to hear speech-in-noise (0.70 and 0.89 dB, respectively) among the population studied. Men subjectively reported up to 60% higher rates of difficulty hearing than women. Workplace noise history associated with difficulty in both subjective hearing and objective speech hearing in noise. Leisure noise history was associated with subjective, but not with objective difficulty hearing.ConclusionsOlder people have declining cognitive processing ability associated with reduced ability to hear speech in noise, measured by recognition of recorded spoken digits. Subjective reports of hearing difficulty generally show a higher prevalence than objective measures, suggesting that current objective methods could be extended further.

Infants' brain responses to speech suggest analysis by synthesis.

Historic theories of speech perception (Motor Theory and Analysis by Synthesis) invoked listeners' knowledge of speech production to explain speech perception. Neuroimaging data show that adult listeners activate motor brain areas during speech perception. In two experiments using magnetoencephalography (MEG), we investigated motor brain activation, as well as auditory brain activation, during discrimination of native and nonnative syllables in infants at two ages that straddle the developmental transition from language-universal to language-specific speech perception. Adults are also tested in Exp. 1. MEG data revealed that 7-mo-old infants activate auditory (superior temporal) as well as motor brain areas (Broca's area, cerebellum) in response to speech, and equivalently for native and nonnative syllables. However, in 11- and 12-mo-old infants, native speech activates auditory brain areas to a greater degree than nonnative, whereas nonnative speech activates motor brain areas to a greater degree than native speech. This double dissociation in 11- to 12-mo-old infants matches the pattern of results obtained in adult listeners. Our infant data are consistent with Analysis by Synthesis: auditory analysis of speech is coupled with synthesis of the motor plans necessary to produce the speech signal. The findings have implications for: (i) perception-action theories of speech perception, (ii) the impact of "motherese" on early language learning, and (iii) the "social-gating" hypothesis and humans' development of social understanding.

Sensorineural hearing loss in very low birth weight infants with histological chorioamnionitis

Objective: Histological chorioamnionitis (HCAM) has been associated with inflammatory diseases of preterm infants. Recently we have observed that it increased the risk of speech delay and hearing loss. So the aim of this study was to evaluate the relationship between sensorineural hearing loss (SNHL) of VLBW infants and HCAM.Methods: We performed an observational study on VLBW infants admitted to the NICU of Padua. Each patient with HCAM was matched with one control without HCAM. All infants underwent hearing screening before discharge by means of automated transient–evoked otoacustic emissions and automated auditory brainstem responses, which were repeated at 3 and 6 months of age with tympanometry measurement. Incidence of SNHL at 6 months of age was compared in the 2 groups and risk factors for hearing loss were studied.Results: Two of 77 (2.6%) newborns with HCAM e 6/73 (8.2%) without it presented SNHL at 6 months of corrected age (p = 0.16). Multivariable logistic regression analysis identified surgical ligation of patent ductus arteriosus (PDA) as independent predictors of SNHL (OR: 5.75, 95% CI 1.34–24.84, p = 0.02), whereas the effect of HCAM on SNHL was only near to statistical significance level.Conclusions: Surgical ligation of PDA is associated with an increased risk of SNHL in VLBW infants, regardless of HCAM.

Deficits in predictive coding underlie hallucinations in schizophrenia.

The neural mechanisms that produce hallucinations and other psychotic symptoms remain unclear. Previous research suggests that deficits in predictive signals for learning, such as prediction error signals, may underlie psychotic symptoms, but the mechanism by which such deficits produce psychotic symptoms remains to be established. We used model-based fMRI to study sensory prediction errors in human patients with schizophrenia who report daily auditory verbal hallucinations (AVHs) and sociodemographically matched healthy control subjects. We manipulated participants' expectations for hearing speech at different periods within a speech decision-making task. Patients activated a voice-sensitive region of the auditory cortex while they experienced AVHs in the scanner and displayed a concomitant deficit in prediction error signals in a similar portion of auditory cortex. This prediction error deficit correlated strongly with increased activity during silence and with reduced volumes of the auditory cortex, two established neural phenotypes of AVHs. Furthermore, patients with more severe AVHs had more deficient prediction error signals and greater activity during silence within the region of auditory cortex where groups differed, regardless of the severity of psychotic symptoms other than AVHs. Our findings suggest that deficient predictive coding accounts for the resting hyperactivity in sensory cortex that leads to hallucinations.

The influence of inner and heard speech in arts speech therapy on brain oxygenation and hemodynamics

Purpose: Artistic speech therapy is applied in anthroposophically extended medicine to treat several diseases. The aim is to understand the physiology by investigating the effect of inner and heard speech on brain hemodynamics and oxygenation and analyzing whether these changes were affected by changes in arterial carbon dioxide pressure. Methods: In 29 healthy adult volunteers changes in cerebral absolute oxyhemoglobin ([O2Hb]), deoxyhemoglobin ([HHb]), total hemoglobin ([tHb]) concentrations and tissue oxygen saturation (StO2) were measured by functional near-infrared spectroscopy (fNIRS). End-tidal CO2 (PETCO2) was assessed by capnography. Each subject performed six tasks: inner speech, heard speech from a person and heard speech from a record with each two different recitation texts: hexameter and alliteration according to a randomized crossover design. Results: Significant changes during tasks: A decrease in StO2, [O2Hb], [tHb] and PETCO2 (only for inner speech); an increase in [HHb]. There was a significant difference between hexameter and alliteration. Particularly, changes in [tHb] at the left prefrontal cortex during tasks and after them were statistically different. Furthermore we found significant relations between changes in [O2Hb], [HHb], [tHb] or StO2 and the participants’ age, the baseline PETCO2, or certain speech tasks. Conclusion: During the inner speech, hyperventilation led to a lower PETCO2 (hypocapnia). During heard speech no significant changes in PETCO2 occurred. But decreases in StO2, [O2Hb], [tHb] suggest hypocapnia also here. Hexameter and alliteration led to different changes in [tHb]. Consequently, our parameters are affected by an interplay of both PETCO2 response and task dependent functional brain activity.