Perception Of Speech Sounds Research Articles

Can speech-evoked Auditory Brainstem Response become a useful tool in clinical practice?

To discuss the clinical applicability of the speech-evoked Auditory Brainstem Response (speech-evoked ABR) to help identifying auditory processing disorders. We analyzed the records of 27 children and adolescents, aged between seven and 15, who presented abnormal speech-evoked ABR. Then, the data from the behavioral auditory processing evaluation of these individuals were surveyed. It was observed that, among the 27 children with abnormal speech-evoked ABR, 23 also had auditory processing disorders. Therefore, from this sample, an 85.15% probability of observing abnormal behavioral assessment of auditory processing in a child who presented abnormal speech-evoked ABR was obtained. It is argued that the speech-evoked ABR can be used in clinical practice as an important aid tool in the diagnosis of auditory processing disorder, because, in this study, an abnormal speech-evoked ABR usually represented a deficit in the results of behavioral assessment of auditory processing. Thus, it can be used to obtain information about the perception of speech sounds in children under seven years or with challenging behavioral assessment.

No evidence of somatotopic place of articulation feature mapping in motor cortex during passive speech perception.

The motor theory of speech perception has experienced a recent revival due to a number of studies implicating the motor system during speech perception. In a key study, Pulvermüller et al. (2006) showed that premotor/motor cortex differentially responds to the passive auditory perception of lip and tongue speech sounds. However, no study has yet attempted to replicate this important finding from nearly a decade ago. The objective of the current study was to replicate the principal finding of Pulvermüller et al. (2006) and generalize it to a larger set of speech tokens while applying a more powerful statistical approach using multivariate pattern analysis (MVPA). Participants performed an articulatory localizer as well as a speech perception task where they passively listened to a set of eight syllables while undergoing fMRI. Both univariate and multivariate analyses failed to find evidence for somatotopic coding in motor or premotor cortex during speech perception. Positive evidence for the null hypothesis was further confirmed by Bayesian analyses. Results consistently show that while the lip and tongue areas of the motor cortex are sensitive to movements of the articulators, they do not appear to preferentially respond to labial and alveolar speech sounds during passive speech perception.

Perception of Speech Sounds in School-Aged Children with Speech Sound Disorders.

Children with speech sound disorders may perceive speech differently than children with typical speech development. The nature of these speech differences is reviewed with an emphasis on assessing phoneme-specific perception for speech sounds that are produced in error. Category goodness judgment, or the ability to judge accurate and inaccurate tokens of speech sounds, plays an important role in phonological development. The software Speech Assessment and Interactive Learning System, which has been effectively used to assess preschoolers' ability to perform goodness judgments, is explored for school-aged children with residual speech errors (RSEs). However, data suggest that this particular task may not be sensitive to perceptual differences in school-aged children. The need for the development of clinical tools for assessment of speech perception in school-aged children with RSE is highlighted, and clinical suggestions are provided.

Retroactive Streaming Fails to Improve Concurrent Vowel Identification.

The sequential organization of sound over time can interact with the concurrent organization of sounds across frequency. Previous studies using simple acoustic stimuli have suggested that sequential streaming cues can retroactively affect the perceptual organization of sounds that have already occurred. It is unknown whether such effects generalize to the perception of speech sounds. Listeners’ ability to identify two simultaneously presented vowels was measured in the following conditions: no context, a preceding context stream (precursors), and a following context stream (postcursors). The context stream was comprised of brief repetitions of one of the two vowels, and the primary measure of performance was listeners’ ability to identify the other vowel. Results in the precursor condition showed a significant advantage for the identification of the second vowel compared to the no-context condition, suggesting that sequential grouping mechanisms aided the segregation of the concurrent vowels, in agreement with previous work. However, performance in the postcursor condition was significantly worse compared to the no-context condition, providing no evidence for an effect of stream segregation, and suggesting a possible interference effect. Two additional experiments involving inharmonic (jittered) vowels were performed to provide additional cues to aid retroactive stream segregation; however, neither manipulation enabled listeners to improve their identification of the target vowel. Taken together with earlier studies, the results suggest that retroactive streaming may require large spectral differences between concurrent sources and thus may not provide a robust segregation cue for natural broadband sounds such as speech.

Effect of frequency lowering and auditory training on speech perception outcome

Abstract The aim of this study was to investigate the effect of auditory training on speech sound perception tasks in patients with steep sloping high-frequency sensorineural hearing loss using amplification with frequency-lowering hearing aids. This study was conducted on 10 adults with steeply sloping high-frequency sensorineural hearing loss using frequency-lowering hearing aids. Pretraining and post-training evaluation tasks were prepared to evaluate the ability to perceive vowels and consonants of Arabic language using lists of consonant-vowel-consonant and vowel-consonant-vowel syllables. Perception tasks included speech sound recognition and discrimination. Arabic exercise tasks were constructed and applied to provide directed training on voiceless consonant speech sounds. The study demonstrated enhancement in consonant perception using frequency lowering, provided the listeners were trained to conjugate between the newly perceived sounds moved to a functional neurophysiological substrate sensitive to lower frequency sounds. Auditory training with frequency-lowering hearing aids improves consonant perception in individuals with steep sloping sensorineural hearing loss.

The perception of speech modulation cues in lexical tones is guided by early language-specific experience.

A number of studies showed that infants reorganize their perception of speech sounds according to their native language categories during their first year of life. Still, information is lacking about the contribution of basic auditory mechanisms to this process. This study aimed to evaluate when native language experience starts to noticeably affect the perceptual processing of basic acoustic cues [i.e., frequency-modulation (FM) and amplitude-modulation information] known to be crucial for speech perception in adults. The discrimination of a lexical-tone contrast (rising versus low) was assessed in 6- and 10-month-old infants learning either French or Mandarin using a visual habituation paradigm. The lexical tones were presented in two conditions designed to either keep intact or to severely degrade the FM and fine spectral cues needed to accurately perceive voice-pitch trajectory. A third condition was designed to assess the discrimination of the same voice-pitch trajectories using click trains containing only the FM cues related to the fundamental-frequency (F0) in French- and Mandarin-learning 10-month-old infants. Results showed that the younger infants of both language groups and the Mandarin-learning 10-month-olds discriminated the intact lexical-tone contrast while French-learning 10-month-olds failed. However, only the French 10-month-olds discriminated degraded lexical tones when FM, and thus voice-pitch cues were reduced. Moreover, Mandarin-learning 10-month-olds were found to discriminate the pitch trajectories as presented in click trains better than French infants. Altogether, these results reveal that the perceptual reorganization occurring during the first year of life for lexical tones is coupled with changes in the auditory ability to use speech modulation cues.

The effect of phonetic production training with visual feedback on the perception and production of foreign speech sounds.

Second-language learners often experience major difficulties in producing non-native speech sounds. This paper introduces a training method that uses a real-time analysis of the acoustic properties of vowels produced by non-native speakers to provide them with immediate, trial-by-trial visual feedback about their articulation alongside that of the same vowels produced by native speakers. The Mahalanobis acoustic distance between non-native productions and target native acoustic spaces was used to assess L2 production accuracy. The experiment shows that 1 h of training per vowel improves the production of four non-native Danish vowels: the learners' productions were closer to the corresponding Danish target vowels after training. The production performance of a control group remained unchanged. Comparisons of pre- and post-training vowel discrimination performance in the experimental group showed improvements in perception. Correlational analyses of training-related changes in production and perception revealed no relationship. These results suggest, first, that this training method is effective in improving non-native vowel production. Second, training purely on production improves perception. Finally, it appears that improvements in production and perception do not systematically progress at equal rates within individuals.

Phonetic training and non-native speech perception — New memory traces evolve in just three days as indexed by the mismatch negativity (MMN) and behavioural measures

Language-specific, automatically responding memory traces form the basis for speech sound perception and new neural representations can also evolve for non-native speech categories. The aim of this study was to find out how a three-day phonetic listen-and-repeat training affects speech perception, and whether it generates new memory traces. We used behavioural identification, goodness rating, discrimination, and reaction time tasks together with mismatch negativity (MMN) brain response registrations to determine the training effects on native Finnish speakers. We trained the subjects the voicing contrast in fricative sounds. Fricatives are not differentiated by voicing in Finnish, i.e., voiced fricatives do not belong to the Finnish phonological system. Therefore, they are extremely hard for Finns to learn. However, only after three days of training, the native Finnish subjects had learned to perceive the distinction. The results show striking changes in the MMN response; it was significantly larger on the second day after two training sessions. Also, the majority of the behavioural indicators showed improvement during training. Identification altered after four sessions of training and discrimination and reaction times improved throughout training. These results suggest remarkable language-learning effects both at the perceptual and pre-attentive neural level as a result of brief listen-and-repeat training in adult participants.

The use of visual information in non-native speech sound discrimination across the first year of life

Infants are able to match seen and heard speech even in non-native languages, and familiarization to audiovisual speech appears to affect subsequent auditory-only discrimination of non-native speech sounds (Danielson et al., 2013; 2014). However, the robustness of these behaviors appears to change rapidly within the first year of life. In this current set of studies, conducted with six-, nine-, and 10-month-old English-learning infants, we examine the developmental trajectory of audiovisual speech perception of non-native speech sounds. In the first place, we show that the tendency to detect a mismatch between heard and seen speech sounds in a non-native language changes across this short period in development, in tandem with the trajectory of auditory perceptual narrowing (Werker & Tees, 1984; Kuhl et al., 1992; inter alia). Furthermore, we demonstrate that infants’ familiarization to matching and mismatching audiovisual speech affects their auditory speech perception differently at various ages. While six-month-old infants’ auditory speech perception appears to be malleable in the face of prior audiovisual familiarization, this tendency declines with age. The current set of studies is one of the first to utilize traditional looking-time measurements while also employing pupillometry as a correlate of infants’ acoustic change detection (Hochmann & Papeo, 2014).

Acoustic change responses to amplitude modulation: a method to quantify cortical temporal processing and hemispheric asymmetry.

Objective: Sound modulation is a critical temporal cue for the perception of speech and environmental sounds. To examine auditory cortical responses to sound modulation, we developed an acoustic change stimulus involving amplitude modulation (AM) of ongoing noise. The AM transitions in this stimulus evoked an acoustic change complex (ACC) that was examined parametrically in terms of rate and depth of modulation and hemispheric symmetry.Methods: Auditory cortical potentials were recorded from 64 scalp electrodes during passive listening in two conditions: (1) ACC from white noise to 4, 40, 300 Hz AM, with varying AM depths of 100, 50, 25% lasting 1 s and (2) 1 s AM noise bursts at the same modulation rate. Behavioral measures included AM detection from an attend ACC condition and AM depth thresholds (i.e., a temporal modulation transfer function, TMTF).Results: The N1 response of the ACC was large to 4 and 40 Hz and small to the 300 Hz AM. In contrast, the opposite pattern was observed with bursts of AM showing larger responses with increases in AM rate. Brain source modeling showed significant hemispheric asymmetry such that 4 and 40 Hz ACC responses were dominated by right and left hemispheres respectively.Conclusion: N1 responses to the ACC resembled a low pass filter shape similar to a behavioral TMTF. In the ACC paradigm, the only stimulus parameter that changes is AM and therefore the N1 response provides an index for this AM change. In contrast, an AM burst stimulus contains both AM and level changes and is likely dominated by the rise time of the stimulus. The hemispheric differences are consistent with the asymmetric sampling in time hypothesis suggesting that the different hemispheres preferentially sample acoustic time across different time windows.Significance: The ACC provides a novel approach to studying temporal processing at the level of cortex and provides further evidence of hemispheric specialization for fast and slow stimuli.

A case of cortical deafness and loss of vestibular and somatosensory sensations caused by cerebrovascular lesions in bilateral primary auditory cortices, auditory radiations, and postcentral gyruses – complete loss of hearing despite normal DPOAE and ABR

Conclusion: A right-handed 38-year-old man’s complete loss of hearing could be diagnosed as cortical deafness caused by cerebral vascular lesions in bilateral auditory cortices. Objective: The aim of this case report was to study the pathophysiology of a particular patient who manifested deafness without residual hearing and lost somatosensory sensation, vestibular sensation, and articulation ability after a right internal carotid-posterior communicating artery (IC-PC) aneurysm and subarachnoidal hemorrhage. Methods: MRI, aphasia and neurological tests, subjective and objective audiometry, and vestibular function tests were performed. Results: The neurological test revealed system loss of somatosensory sensation with normal motor function and articulation ability. Brain imaging revealed extensive infarction in the bilateral primary auditory cortices, postcentral gyruses, and the bilateral partial third frontal gyruses. Pure-tone audiometry of both ears revealed off-the-scale results and speech audiometry demonstrated 0% maximum speech discrimination. However, objective audiometry showed normal distortion product otoacoustic emissions (DPOAE) and normal auditory brainstem response (ABR). The patient showed 0% perception of environmental, speech, and music sounds in both ears. He was unable to feel vestibular sensation despite normal caloric nystagmus. He showed no damage to his larynx or articulation organs.

Patterns of Misperception of Arabic Consonants

There has been much investigation into perception of speech sounds, demonstrating a range of influences including listeners’ native language (e.g. Cutler et al. 2004), the sounds’ position in the syllable (e.g. Wang and Bilger 1973), and the presence of different types of masking noise (e.g. Phatak, Lovitt, and Allen 2008). However, there is no data on patterns of misperception of guttural consonants (uvulars, pharyngeals, and glottals); data on consonant discrimination in Arabic (e.g. Kishon-Rabin and Rosenhouse 2000) and the phonological characteristics of gutturals (cf. McCarthy 1994) suggest that they may pattern distinctly from consonants with other places of articulation. The study introduced here will investigate patterns in directionality of misperception of guttural consonants by presenting syllables containing guttural and non-guttural consonants in noise to be identified by native and non-native speakers of Arabic. While there have been studies on how patterns of misperception of phonological structure differ depending on whether the structure is licit or not within the listener’s native language (e.g. Dupoux et al. 1999), there have been few studies on the patterns of misperception that are present in identification of structures which are licit within a language. This study investigates such patterns and how they differ between guttural and non-guttural consonants.

A comparison of acoustic and perceptual changes in children’s productions of American English /r/

Speech-language pathologists rely primarily on their perceptual judgments when evaluating whether children have made progress in speech sound therapy. Speech sound perception in normal listeners has been characterized as largely categorical, such that slight articulatory changes may go unnoticed unless they reach a specific acoustic signature assigned to a different category. While perception may be categorical, acoustic phenomena are largely measured in continuous units, meaning that there is a potential mismatch between the two methods of recording change. Clinicians, using perceptual categorization, commonly report that some children make no progress in therapy, yet acoustically, the children’s productions may be shifting toward acceptable acoustic characteristics. Using subtle changes in the acoustic signal during therapy could potentially prevent these clients from being discharged due to a perceived lack of progress. This poster evaluates acoustic changes compared to perceptual changes in children’s productions of the American English phoneme /r/ after receiving speech therapy using ultrasound supplemented with telepractice home practice. Preliminary data indicate that there are significant differences between participants’ acoustic values of /r/ and perceptual ratings by clinicians.

Effects of fast, slow, and adaptive amplitude compression on children's and adults' perception of meaningful acoustic information.

Fast- and slow-acting amplitude compression parameters have complementary strengths and weaknesses that limit the full benefit of this feature to hearing aid users. Adaptive time constants have been suggested in the literature as a means of optimizing the benefits of amplitude compression. The purpose of this study was to compare the effects of three amplitude compression release times (slow, fast, and adaptive) on children's and adults' accuracy for categorizing speech and environmental sounds. Participants were asked to categorize speech or environmental sounds embedded in short trials containing low-level playground noise. Stimulus trials included either a high-level environmental sound followed by a lower-level speech stimulus (word) or a high-level speech stimulus followed by a lower-level environmental sound. The listeners responded to the second (low-level) stimulus in each trial. The two stimuli overlapped temporally in half of the trials but not in the other half. The stimulus trials were processed to simulate amplitude compression having fast (40 msec), slow (800 msec), or adaptive release times. The adaptive-compression parameters operated in a slow fashion until a sudden increase/decrease in level required a rapid change in gain. Participants were 15 children and 26 adults with hearing loss (HL) as well as 20 children and 21 adults with normal hearing (NH). DATA COLLECTION AND ANALYSES: Performance (in % correct) was arcsine transformed and subjected to repeated-measures analysis of variance with pairwise comparisons of significant main effects using Bonferroni adjustments for multiple comparisons. Overall, the performance of listeners with HL was poorer than that of the listeners with NH and performance for the environmental sounds was poorer than for the speech stimuli, particularly for the adults and children with HL. Significant effects of age group, stimulus overlap, and compression speed were observed for the listeners with NH, whereas effects of stimulus overlap and compression speed were found for the listeners with HL. Whereas listeners with NH achieved optimal performance with slow-acting compression, the listeners with HL achieved optimal performance with adaptive compression. Although slow, fast, and adaptive compression affects the acoustic signal in a subtle fashion, amplitude compression significantly affects perception of speech and environmental sounds.

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.

Exploration of flat hearing protector attenuation and sound detection in noise

Flat-response devices are a class of hearing protectors with nearly uniform attenuation across frequency. These devices can protect the individual wearer while maintaining the spectral balance of the surrounding sounds. This is typically achieved by reducing the muffling effect of conventional hearing protectors which provide larger attenuation at higher than lower frequencies, especially with earmuffs. Flat hearing protectors are often recommended when good speech communication or sound perception is essential, especially for wearers with high-frequency hearing loss, to maintain audibility at all frequencies. However, while flat-response devices are described in some acoustical standards, the tolerance limits for the definition of flatness are largely unspecified and relatively little is known on the exact conditions when such devices can be beneficial. The purpose of this study is to gain insight into the interaction between the spectrum of the noise, the shape of the attenuation-frequency response, and the hearing loss configuration on detection thresholds using a psychoacoustic model of sound detection in noise.

Dissociating Contributions of the Motor Cortex to Speech Perception and Response Bias by Using Transcranial Magnetic Stimulation.

Recent studies using repetitive transcranial magnetic stimulation (TMS) have demonstrated that disruptions of the articulatory motor cortex impair performance in demanding speech perception tasks. These findings have been interpreted as support for the idea that the motor cortex is critically involved in speech perception. However, the validity of this interpretation has been called into question, because it is unknown whether the TMS-induced disruptions in the motor cortex affect speech perception or rather response bias. In the present TMS study, we addressed this question by using signal detection theory to calculate sensitivity (i.e., d′) and response bias (i.e., criterion c). We used repetitive TMS to temporarily disrupt the lip or hand representation in the left motor cortex. Participants discriminated pairs of sounds from a “ba”–“da” continuum before TMS, immediately after TMS (i.e., during the period of motor disruption), and after a 30-min break. We found that the sensitivity for between-category pairs was reduced during the disruption of the lip representation. In contrast, disruption of the hand representation temporarily reduced response bias. This double dissociation indicates that the hand motor cortex contributes to response bias during demanding discrimination tasks, whereas the articulatory motor cortex contributes to perception of speech sounds.

An fMRI Study of Impairments to Speech Perception in Patients with Vascular Sensory Aphasia

The aim of the present work was to use the noninvasive fMRI method to identify neurophysiological correlates of impairments at the sensory stage of the perception of verbal information, i.e., phonematic hearing, in patients with sensory aphasia after acute impairments to cerebral circulation in the left hemisphere of the brain. This was addressed by recording the fMRI equivalent of mismatch negativity in response to verbal phonemes – the syllables “ba” and “pa” – using the oddball paradigm in 20 healthy subjects and 23 patients with post-stroke sensory aphasia. Calculation of mismatch negativity contrast in healthy subjects identified activation of the superior temporal and inferior frontal gyri in the right and left hemispheres. Patients showed significant activation of the auditory zone of the cortex only in the right hemisphere, activation at this site was less marked in terms of volume and intensity than in healthy subjects, and correlated with the extent of speech preservation. Thus, recording of the fMRI equivalent of mismatch negativity provides a sensitive method for studies of impaired perception of speech sounds.

Neural Systems Underlying Perceptual Adjustment to Non-Standard Speech Tokens.

It has long been noted that listeners use top-down information from context to guide perception of speech sounds. A recent line of work employing a phenomenon termed 'perceptual learning for speech' shows that listeners use top-down information to not only resolve the identity of perceptually ambiguous speech sounds, but also to adjust perceptual boundaries in subsequent processing of speech from the same talker. Even so, the neural mechanisms that underlie this process are not well understood. Of particular interest is whether this type of adjustment comes about because of a retuning of sensitivities to phonetic category structure early in the neural processing stream or whether the boundary shift results from decision-related or attentional mechanisms further downstream. In the current study, neural activation was measured using fMRI as participants categorized speech sounds that were perceptually shifted as a result of exposure to these sounds in lexically-unambiguous contexts. Sensitivity to lexically-mediated shifts in phonetic categorization emerged in right hemisphere frontal and middle temporal regions, suggesting that the perceptual learning for speech phenomenon relies on the adjustment of perceptual criteria downstream from primary auditory cortex. By the end of the session, this same sensitivity was seen in left superior temporal areas, which suggests that a rapidly-adapting system may be accompanied by more slowly evolving shifts in regions of the brain related to phonetic processing.

The perception and production of English speech sounds by Cantonese ESL learners in Hong Kong

This article discusses the perception and production of English speech sounds by Cantonese ESL learners in Hong Kong and examines the validity of the claims of the Speech Learning Model for explaining second language speech production by Hong Kong Cantonese ESL learners. Forty university English majors participated in the study, which included two L2 speech perception tasks, two L1 L2 speech perception tasks, and three L2 speech production tasks. It is found that although the perceived similarity between the L1 and the L2 is inversely related to L2 speech perception, such an inverse relationship between perceived L1 L2 similarity and L2 speech production is not so straightforward and is often mediated by other widespread phonological phenomena such as final obstruent devoicing and final lateral vocalization. Speech perception and speech production, thus, do not bear a strict one-to-one relation, and correct discernment of a target sound does not necessarily lead to correct production. The predictions of the SLM regarding speech production do not seem to be entirely borne out. Further research is needed to investigate the perceptual and production abilities of ESL learners of other linguistic backgrounds.