Speech Perception Development Research Articles

Speech perception, production and intelligibility in French-speaking children with profound hearing loss and early cochlear implantation after congenital cytomegalovirus infection

ObjectiveTo analyze speech in children with profound hearing loss following congenital cytomegalovirus (cCMV) infection with cochlear implantation (CI) before the age of 3 years. Material and methodsIn a cohort of 15 children with profound hearing loss, speech perception, production and intelligibility were assessed before and 3 years after CI; variables impacting results were explored. ResultsPost-CI, median word recognition was 74% on closed-list and 48% on open-list testing; 80% of children acquired speech production; and 60% were intelligible for all listeners or listeners attentive to lip-reading and/or aware of the child's hearing loss. Univariate analysis identified 3 variables (mean post-CI hearing threshold, bilateral vestibular areflexia, and brain abnormality on MRI) with significant negative impact on the development of speech perception, production and intelligibility. ConclusionCI showed positive impact on hearing and speech in children with post-cCMV profound hearing loss. Our study demonstrated the key role of maximizing post-CI hearing gain. A few children had insufficient progress, especially in case of bilateral vestibular areflexia and/or brain abnormality on MRI. This led us to suggest that balance rehabilitation and speech therapy should be intensified in such cases.

Too noisy for toddlers

Excessive background noise may affect speech perception and language development in toddlers.

Assessment of Developing Speech Perception in Preterm Infants Using Near-Infrared Spectroscopy

Despite improved survival rates of infants, higher brain dysfunction in surviving infants remains a considerable problem. Most infants with higher brain dysfunctions are born preterm. Magnetic resonance imaging (MRI) is a useful tool to detect structural brain damage and provides important information to evaluate the neurologic sequelae of such preterm infants. Although MRI can reveal detailed brain structure, it is not the best option to assess brain function in preterm infants because of various restrictions. To overcome this difficulty, a new imaging technique, called functional near infrared spectroscopy (fNIRS), can be used to evaluate brain function in preterm infants. fNIRS is a suitable method to examine infants because, unlike MRI, it is not necessary to restrict movement and it is silent. In this review, we focus on language function, an important higher human brain function and one of the most prominent difficulties among grown preterm infants. We describe the development of speech perception in infants from preterm to age 1 year. First, we discuss the development of the brain hemodynamic response to speech stimulation in full-term infants, imaged using fNIRS. Second, we discuss the functional specialization in full-term infants for speech processing in the cerebral cortex as revealed by fNIRS. Third, we discuss potential interpretations of developmental changes in brain activation during speech perception in preterm infants. We present data that reveal the development of speech processing in full-term and preterm infants. We conclude that fNIRS can aid in the anticipation of language delay in preterm infants and may facilitate early intervention and treatment of such dysfunctions.

Development of early auditory and speech perception skills within one year after cochlear implantion in prelingual deaf children

To investigate the development of early auditory capability and speech perception in the prelingual deaf children after cochlear implantation, and to study the feasibility of currently available Chinese assessment instruments for the evaluation of early auditory skill and speech perception in hearing-impaired children. A total of 83 children with severe-to-profound prelingual hearing impairment participated in this study. Participants were divided into four groups according to the age for surgery: A (1-2 years), B (2-3 years), C (3-4 years) and D (4-5 years). The auditory skill and speech perception ability of CI children were evaluated by trained audiologists using the infant-toddler/meaningful auditory integration scale (IT-MAIS/MAIS) questionnaire, the Mandarin Early Speech Perception (MESP) test and the Mandarin Pediatric Speech Intelligibility (MPSI) test. The questionnaires were used in face to face interviews with the parents or guardians. Each child was assessed before the operation and 3 months, 6 months, 12 months after switch-on. After cochlear implantation, early postoperative auditory development and speech perception gradually improved. All MAIS/IT-MAIS scores showed a similar increasing trend with the rehabilitation duration (F=5.743, P=0.007). Preoperative and post operative MAIS/IT-MAIS scores of children in age group C (3-4 years) was higher than that of other groups. Children who had longer hearing aid experience before operation demonstrated higher MAIS/IT-MAIS scores than those with little or no hearing aid experience (F=4.947, P=0.000). The MESP test showed that, children were not able to perceive speech as well as detecting speech signals. However as the duration of CI use increased, speech perception ability also improved substantially. However, only about 40% of the subjects could be evaluated using the most difficult subtest on the MPSI in quiet at 12 months after switch-on. As MCR decreased, the proportion of children who could be tested using the MPSI reduced. Within one year after CI, children develop early auditory and speech perception capabilities with time. Chinese versions of the IT-MAIS/MAIS, MESP and MPSI are useful instruments to document early auditory and speech perception skills in children after CI implantation.

Language specific listening of Japanese geminate consonants: a cross-linguistic study.

Various aspects of linguistic experience influence the way we segment, represent, and process speech signals. The Japanese phonetic and orthographic systems represent geminate consonants (double consonants, e.g., /ss/, /kk/) in a unique way compared to other languages: one abstract representation is used to characterize the first part of geminate consonants despite the acoustic difference between two distinct realizations of geminate consonants (silence in the case of e.g., stop consonants and elongation in the case of fricative consonants). The current study tests whether this discrepancy between abstract representations and acoustic realizations influences how native speakers of Japanese perceive geminate consonants. The experiments used pseudo words containing either the geminate consonant /ss/ or a manipulated version in which the first part was replaced by silence /_s/. The sound /_s/ is acoustically similar to /ss/, yet does not occur in everyday speech. Japanese listeners demonstrated a bias to group these two types into the same category while Italian and Dutch listeners distinguished them. The results thus confirmed that distinguishing fricative geminate consonants with silence from those with sustained frication is not crucial for Japanese native listening. Based on this observation, we propose that native speakers of Japanese tend to segment geminated consonants into two parts and that the first portion of fricative geminates is perceptually similar to a silent duration. This representation is compatible with both Japanese orthography and phonology. Unlike previous studies that were inconclusive in how native speakers segment geminate consonants, our study demonstrated a relatively strong effect of Japanese specific listening. Thus the current experimental methods may open up new lines of investigation into the relationship between development of phonological representation, orthography and speech perception.

Development of speech perception under adverse listening conditions

Speech communication success is dependent on interactions among the talker, listener, and listening environment. One such important interaction is between the listener’s age and the noise and reverberation in the environment. Previous work has demonstrated that children have greater difficulty than adults in noisy and highly reverberant environments, such as those frequently found in classrooms. I will review research that considers how a talker’s production patterns also contribute to speech comprehension, focusing on nonnative talkers. Studies from my lab have demonstrated that children have more difficulty than adults perceiving speech that deviates from native language norms, even in quiet listening conditions in which adults are highly accurate. When a nonnative talker’s voice was combined with noise, children’s word recognition was particularly poor. Therefore, similar to the developmental trajectory for speech perception in noise or reverberation, the ability to accurately perceive speech produced by nonnative talkers continues to develop well into childhood. Metrics to quantify speech intelligibility in specific rooms must consider both listener characteristics, talker characteristics, and their interaction. Future research should investigate how children’s speech comprehension is influenced by the interaction between specific types of background noise and reverberation and talker production characteristics. [Work supported by NIH-R21DC010027.]

Acoustics-related research in the Department of Speech and Hearing Sciences at Indiana University

In the Department of Speech and Hearing Sciences at Indiana University, there are many highly active laboratories that conduct research on a wide range of areas in acoustics. Four of these laboratories are described below. The Biophysics Lab (PI: Robert Withnell) focuses on the mechanics of hearing. Acoustically based signal processing and data acquisition provide experimental data for model-based analysis of peripheral sound processing. The Comparative Perception Lab (PI: William Shofner) focuses on how the physical features of complex sounds are related to their perceptual attributes, particularly pitch and speech. Understanding behavior and perception in animals, particularly in chinchillas, is an essential component of the research. The Speech Production Laboratory (PI: Steven Lulich) conducts research on imaging of the tongue and oral cavity, speech breathing, and acoustic modeling of the whole vocal/respiratory tract. Laboratory equipment includes 3D/4D ultrasound, digitized palate impressions, whole-body and inductive plethysmography, electroglottography, oral and nasal pressure and flow recordings, and accelerometers. The Speech Perception Lab (PI: Tessa Bent) focuses on the perceptual consequences of phonetic variability in speech, particularly foreign-accented speech. The main topics under investigation are perceptual adaptation, individual differences in word recognition, and developmental speech perception.

Critical Periods in Speech Perception: New Directions

A continuing debate in language acquisition research is whether there are critical periods (CPs) in development during which the system is most responsive to environmental input. Recent advances in neurobiology provide a mechanistic explanation of CPs, with the balance between excitatory and inhibitory processes establishing the onset and molecular brakes establishing the offset of windows of plasticity. In this article, we review the literature on human speech perception development within the context of this CP model, highlighting research that reveals the interplay of maturational and experiential influences at key junctures in development and presenting paradigmatic examples testing CP models in human subjects. We conclude with a discussion of how a mechanistic understanding of CP processes changes the nature of the debate: The question no longer is, "Are there CPs?" but rather what processes open them, keep them open, close them, and allow them to be reopened.

La perception de la parole de 0 à 24 mois

The development of speech perception relies upon early auditory capacities (i.e. discrimination, segmentation and representation). Infants are able to discriminate most of the phonetic contrasts occurring in natural languages, and at the end of the first year, this universal ability starts to narrow down to the contrasts used in the environmental language. During the second year, this specialization is characterized by the development of comprehension, lexical organization and word production. That process appears now as the result of multiple interactions between perceptual, cognitive and social developing abilities. Distinct factors like word acquisition, sensitivity to the statistical properties of the input, or even the nature of the social interactions, might play a role at one time or another during the acquisition of phonological patterns. Experience with the native language is necessary for phonetic segments to be functional units of perception and for speech sound representations (words, syllables) to be more specified and phonetically organized. This evolution goes on beyond 24 months of age in a learning context characterized from the early stages by the interaction with other developing (linguistic and non-linguistic) capacities.

Theta–gamma coupling reflects the interaction of bottom-up and top-down processes in speech perception in children

This study investigates how the interaction of different brain oscillations (particularly theta–gamma coupling) modulates the bottom-up and top-down processes during speech perception. We employed a speech perception paradigm that manipulated the congruency between a visually presented picture and an auditory stimulus and asked participants to judge whether they matched or mismatched. A group of children (mean age 10years, 5months) participated in this study and their electroencephalographic (EEG) data were recorded while performing the experimental task. It was found that in comparison with mismatch condition, match condition facilitated speech perception by eliciting greater theta–gamma coupling in the frontal area and smaller theta–gamma coupling in the left temporal area. These findings suggested that a top-down facilitation effect from congruent visual pictures engaged different mechanisms in low-level sensory (temporal) regions and high-level linguistic and decision (frontal) regions. Interestingly, hemispheric asymmetry is with higher theta–gamma coupling in the match condition in the right hemisphere and higher theta–gamma coupling in the mismatch condition in the left hemisphere. This indicates that a fast global processing strategy and a slow detailed processing strategy were differentially adopted in the match and mismatch conditions. This study provides new insight into the mechanisms of speech perception from the interaction of different oscillatory activities and provides neural evidence for theories of speech perception allowing for top-down feedback connections. Furthermore, it sheds light on children's speech perception development by showing a similar pattern of integration of bottom-up and top-down information during speech perception as previous studies have revealed in adults.

Don’t Listen With Your Mouth Full: The Role of Facial Motor Action in Visual Speech Perception

Theories of speech perception agree that visual input enhances the understanding of speech but disagree on whether physically mimicking the speaker improves understanding. This study investigated whether facial motor mimicry facilitates visual speech perception by testing whether blocking facial motor action impairs speechreading performance. Thirty-five typically developing children (19 boys; 16 girls; M age = 7 years) completed the Revised Craig Lipreading Inventory under two conditions. While observing silent videos of 15 words being spoken, participants either held a tongue depressor horizontally with their teeth (blocking facial motor action) or squeezed a ball with one hand (allowing facial motor action). As hypothesized, blocking motor action resulted in fewer correctly understood words than that of the control task. The results suggest that facial mimicry or other methods of facial action support visual speech perception in children. Future studies on the impact of motor action on the typical and atypical development of speech perception are warranted.

초기 음소 지각 능력 발달에서 입력 언어의 역할 탐색

초기 음소 지각 능력 발달에서 입력 언어의 역할 탐색

Developmental changes in mismatch responses to mandarin consonants and lexical tones from early to middle childhood.

The purpose of this study was to use mismatch responses (MMRs) to explore the dynamic changes of Mandarin speech perception abilities from early to middle childhood. Twenty preschoolers, 18 school-aged children, and 26 adults participated in this study. Two sets of synthesized speech stimuli varying in Mandarin consonant (alveolo-palatal affricate vs. fricative) and lexical tone features (rising vs. contour tone) were used to examine the developmental course of speech perception abilities. The results indicated that only the adult group demonstrated typical early mismatch negativity (MMN) responses, suggesting that the ability to discriminate specific speech cues in Mandarin consonant and lexical tone is a continuing process in preschool- and school-aged children. Additionally, distinct MMR patterns provided evidence indicating diverse developmental courses to different speech characteristics. By incorporating data from the two speech conditions, we propose using MMR profiles consisting of mismatch negativity (MMN), positive mismatch response (p-MMR), and late discriminative negativity (LDN) as possible brain indices to investigate speech perception development.

Caregiver influence on looking behavior and brain responses in prelinguistic development.

Much is known about the development of speech perception, but there remain gaps in understanding in the development of speech production. Social interaction is a popular topic among researchers of human development, and the development of speech production is clearly dependent upon social interaction (Goldstein et al., 2003; Goldstein and Schwade, 2008). The importance of social interaction becomes particularly apparent when infants begin to speak the language of their ambient environment (Lewkowicz and Hansen-Tift, 2012). Prior to first word production, however, an exchange between caregivers and infants occurs, such that infant vocalizations and other changes in development directly influence caregiver responses, which in turn influence various components of interaction.

Brief report: Arrested development of audiovisual speech perception in autism spectrum disorders.

Atypical communicative abilities are a core marker of Autism Spectrum Disorders (ASD). A number of studies have shown that, in addition to auditory comprehension differences, individuals with autism frequently show atypical responses to audiovisual speech, suggesting a multisensory contribution to these communicative differences from their typically developing peers. To shed light on possible differences in the maturation of audiovisual speech integration, we tested younger (ages 6-12) and older (ages 13-18) children with and without ASD on a task indexing such multisensory integration. To do this, we used the McGurk effect, in which the pairing of incongruent auditory and visual speech tokens typically results in the perception of a fused percept distinct from the auditory and visual signals, indicative of active integration of the two channels conveying speech information. Whereas little difference was seen in audiovisual speech processing (i.e., reports of McGurk fusion) between the younger ASD and TD groups, there was a significant difference at the older ages. While TD controls exhibited an increased rate of fusion (i.e., integration) with age, children with ASD failed to show this increase. These data suggest arrested development of audiovisual speech integration in ASD. The results are discussed in light of the extant literature and necessary next steps in research.

Infant directed speech and the development of speech perception: Enhancing development or an unintended consequence?

Infant directed speech (IDS) is a speech register characterized by simpler sentences, a slower rate, and more variable prosody. Recent work has implicated it in more subtle aspects of language development. Kuhl et al. (1997) demonstrated that segmental cues for vowels are affected by IDS in a way that may enhance development: the average locations of the extreme “point” vowels (/a/, /i/ and /u/) are further apart in acoustic space. If infants learn speech categories, in part, from the statistical distributions of such cues, these changes may specifically enhance speech category learning. We revisited this by asking (1) if these findings extend to a new cue (Voice Onset Time, a cue for voicing); (2) whether they extend to the interior vowels which are much harder to learn and/or discriminate; and (3) whether these changes may be an unintended phonetic consequence of factors like speaking rate or prosodic changes associated with IDS. Eighteen caregivers were recorded reading a picture book including minimal pairs for voicing (e.g., beach/peach) and a variety of vowels to either an adult or their infant. Acoustic measurements suggested that VOT was different in IDS, but not in a way that necessarily supports better development, and that these changes are almost entirely due to slower rate of speech of IDS. Measurements of the vowel suggested that in addition to changes in the mean, there was also an increase in variance, and statistical modeling suggests that this may counteract the benefit of any expansion of the vowel space. As a whole this suggests that changes in segmental cues associated with IDS may be an unintended by-product of the slower rate of speech and different prosodic structure, and do not necessarily derive from a motivation to enhance development.

The Acquisitional Value of Recasts in Instructed Second Language Speech Learning: Teaching the Perception and Production of English /ɹ/ to Adult Japanese Learners

The current study investigated the impact of recasts together with form‐focused instruction (FFI) on the development of second language speech perception and production of English /ɹ/ by Japanese learners. Forty‐five learners were randomly assigned to three groups—FFI recasts, FFI only, and Control—and exposed to four hours of communicatively oriented lessons. Whereas many FFI activities including explicit instruction were embedded into the treatment in order for the experimental groups to notice and practice /ɹ/ in a meaningful discourse, an instructor provided recasts only to the FFI‐recast group in response to their mispronunciation of /ɹ/. Perception was measured using a two‐alternative forced choice identification task, while pronunciation performance was elicited using controlled and spontaneous production tests and assessed by 10 naïve native‐speaking listeners. According to the statistical comparisons, whereas the FFI‐only group attained perception and production improvement particularly under trained lexical conditions, the FFI‐recast group demonstrated similar but generalizable gains both in trained and untrained lexical contexts. The results indicate that (a) FFI itself impacts various domains of L2 speech learning processes (perception, controlled, and spontaneous production) and (b) recasts promote learners’ attentional shift away from lexical units as a whole to phonetic aspects of second language speech (i.e., vocabulary to sound learning).

Communicative focus on second language phonetic form: Teaching Japanese learners to perceive and produce English /ɹ/ without explicit instruction

ABSTRACTThe current study examines in depth how two types of form-focused instruction (FFI), which are FFI with and without corrective feedback (CF), can facilitate second language speech perception and production of /ɹ/ by 49 Japanese learners in English as a Foreign Langage settings. FFI effectiveness was assessed via three outcome measures (perception, controlled production, and spontaneous production) and also according to two lexical contexts (trained and untrained items). Two experimental groups received 4 hr of FFI treatment to notice and practice the target feature of /ɹ/ (but without any explicit instruction) in meaningful discourse. A control group (n= 14) received comparable instruction in the absence of FFI. During FFI, the instructors provided CF only to students in the FFI + CF group (n= 18) by recasting their mispronunciations of /ɹ/, while no CF was provided to those in the FFI-only group (n= 17). Analyses of pre- and posttests showed that FFI itself can sufficiently promote the development of speech perception and production of /ɹ/ and the acquisitional value of CF in second language speech learning remains unclear. The results suggest that the beginner learners without much phonetic knowledge on how to repair their mispronunciation of /ɹ/ should be encouraged to learn the target sound only through FFI in a receptive mode without much pressure for modified output.

Lip Movements Affect Infants’ Audiovisual Speech Perception

Speech is robustly audiovisual from early in infancy. Here we show that audiovisual speech perception in 4.5-month-old infants is influenced by sensorimotor information related to the lip movements they make while chewing or sucking. Experiment 1 consisted of a classic audiovisual matching procedure, in which two simultaneously displayed talking faces (visual [i] and [u]) were presented with a synchronous vowel sound (audio /i/ or /u/). Infants’ looking patterns were selectively biased away from the audiovisual matching face when the infants were producing lip movements similar to those needed to produce the heard vowel. Infants’ looking patterns returned to those of a baseline condition (no lip movements, looking longer at the audiovisual matching face) when they were producing lip movements that did not match the heard vowel. Experiment 2 confirmed that these sensorimotor effects interacted with the heard vowel, as looking patterns differed when infants produced these same lip movements while seeing and hearing a talking face producing an unrelated vowel (audio /a/). These findings suggest that the development of speech perception and speech production may be mutually informative.

Long term speech perception after cochlear implant in pediatric patients with GJB2 mutations

To determine the long term effect of cochlear implant (CI) in children with GJB2-related deafness in Japan. Genetic testing was performed on 29 children with CI. The speech perception in 9 children with GJB2 gene-related deafness fitted with CI was compared with those in matched 10 children who were diagnosed as having no genetic loci. The average follow-up period after CI was 55.9 months and 54.6 months, respectively. A definitive inherited hearing impairment could be confirmed in 12 (41.4%) of the 29 CI children, including 10 with GJB2-related hearing impairment and 2 with SLC26A4-related hearing impairment. The results of IT-MAIS, word or speech perception testing under the noise, and development of speech perception and production testing using the Enjoji scale were slightly better for the GJB2 group after CI than for the control group without statistical significant difference. The long-term results of this study show that CI is also effective in the development of speech performance after CI in Japanese children with GJB2-related hearing impairments as HL due to other etiologies.