Deaf Infants Research Articles

Cochlear Implantation in Deaf Infants

With the application of universal newborn hearing screening programs, a large pool of newly identified deaf infants has been identified. The benefits of early intervention with cochlear implants (CI) is being explored. Mounting evidence suggests that age at implantation is a strong predictor of language outcomes. However, new behavioral procedures are needed to measure speech and language skills during infancy. Also, procedures are needed to analyze the speech input to young CI recipients. Cohort-sequential. Thirteen infants with profound hearing loss who were implanted between the ages of 6 to 12 months of age participated in this study. Eight participated in two new behavioral methodologies: 1) the visual habituation procedure to assess their discrimination of speech sounds; 2) the preferential looking paradigm to assess their ability to learn associations between speech sounds and objects. Older implanted infants and normal-hearing infants were also tested for comparison. The pitch of mothers' speech to infants was analyzed. Patterns of looking times for the very early implanted infants were similar to those of normal hearing infants. Mothers' speech to infants with CIs was similar in pitch to normal-hearing infants who had the same duration of experience with sounds. No surgical or anesthetic complications occurred in this group of infants, and the pattern of listening skill development mirrors that seen in normal-hearing infants. Mothers adjust their speech to suit the listening experience of their infants.

The Impact of Visual Communication on the Intersubjective Development of Early Parent-Child Interaction With 18- to 24-Month-Old Deaf Toddlers

This article presents a study that examined the impact of visual communication on the quality of the early interaction between deaf and hearing mothers and fathers and their deaf children aged between 18 and 24 months. Three communication mode groups of parent-deaf child dyads that differed by the use of signing and visual-tactile communication strategies were involved: (a) hearing parents communicating with their deaf child in an auditory/oral way, (b) hearing parents using total communication, and (c) deaf parents using sign language. Based on Loots and colleagues' intersubjective developmental theory, parent-deaf child interaction was analyzed according to the occurrence of intersubjectivity during free play with a standard set of toys. The data analyses indicated that the use of sign language in a sequential visual way of communication enabled the deaf parents to involve their 18- to 24-month-old deaf infants in symbolic intersubjectivity, whereas hearing parents who hold on to oral-only communication were excluded from involvement in symbolic intersubjectivity with their deaf infants. Hearing parents using total communication were more similar to deaf parents, but they still differed from deaf parents in exchanging and sharing symbolic and linguistic meaning with their deaf child.

Cochlear implantation in children younger than 12 months of age

For decades there has been a trend to complete cochlear implantation in younger deaf individuals. This has led to the current Food and Drug Administration (FDA) approved minimum age of 12 months. Universal infant hearing screening combined with better assessment techniques has resulted in much earlier diagnosis of deafness in infants, and as a consequence, most congenitally deaf children have completed cochlear implant evaluation before the age of 6 months. Because of these issues, there are a growing number of infants who are undergoing cochlear implantation between the ages of 6 and 12 months of age. This article reviews important technical details that should be considered when an infant undergoes cochlear implantation.

Comparison of vocalization development between normal and congenitally hearing impaired infants during pre-language period

To compare the characteristics of vocalization and relevant perceptual characteristics between normal hearing infants and congenitally hearing impaired infants during pre-language period. Speech spectrograms were analyzed, and the presentation time and frequency of pre-canonical babbling, canonical babbling, pointing behaviors and meaningful words were compared and statistically analyzed among 18 normal hearing infants, 11 profoundly congenitally hearing impaired infants that were divided into 2 groups: group A of deaf infants (n = 11) to be aided before 8 months of age and group B of deaf infant (n = 17) to be aided after 8 months of age. There was no significant difference in the presentation time and frequency of pre-canonical babbling among the 3 groups. Canonical babbling, pointing behaviors and meaningful words occurred the earliest and with the highest frequency in the normal hearing group, followed by the group A of deaf infants and group B of deaf infants in succession. Pre-canonical babbling appears in profoundly hearing impaired infants, suggesting that it is a kind of phonation activity free of hearing feedback. Better language development can be achieved when early intervention is carried out for congenitally hearing impaired infants within 8 months of age.

Introduction to the special issue on critical periods reexamined: Evidence from human sensory development

Several decades ago, evidence for critical periods emerged in animal research on imprinting and on visual development. In both cases, input early in life altered the behavioral responses of the animal to later input (e.g., to conspecifics, to fine detail) and induced observable changes in the nervous system. These effects occurred during a critical period shortly after birth, such that the comparable manipulation later in life had no effect. Based on these findings, some scientists drew the inference that the nervous system loses plasticity after infancy; however, recent studies of humans with a variety of sensory deficits indicate considerable residual plasticity even in adulthood (e.g., Levi, Polat, & Hu, 1997; Ramachandran & Rogers-Ramachandran, 2000; Taub, Uswatte, & Elbert, 2002). In this special issue, recent evidence on human sensory development is used to reexamine the concept of critical period. The articles draw on evidence from three sensory modalities: vision, audition, and touch. The authors examine the effects of both natural variations in experience during normal development and perturbations to development, in each case examining the effect of the timing of input. Collectively, the articles provide new insights on the concept of critical periods and the limits to plasticity in human development. The special issue ends with a commentary by Mark Johnson. Contributors: George F. Michel & Ambler N. Tyler: Critical period: A history of the transition from questions of when, to what, to how. Terri L. Lewis & Daphne Maurer: Multiple sensitive periods in humanvision: Evidence from visually deprived children. Scania de Schonen, S. Sangrigoli, R. Camps, J. Mancini, E. Maes, & A. Laurent: Early brain lesions and face-processing development. Kathryn M. Murphy, Brett R. Beston, Philip M. Boley, & David G. Jones: Development of human visual cortex: A balance between excitatory and inhibitory plasticity mechanisms. Dennis M. Levi: Perceptual learning in adults with amblyopia: A reevaluation of critical periods in human vision. Janet Werker & Richard Tees: Speech perception as a window for understanding plasticity and commitment in language systems of the brain. Robert V. Harrison, Karen A. Gordon, & Richard J. Mount: Is there a critical period for cochlear implantation in congenitally deaf infants? Analysis of hearing and speech perception performance after implantation. Laurel Trainor: Are there critical periods for musical development? Krish Sathian: Visual cortical activity during tactile perception in the sighted and visually deprived. Mark Johnson: Sensitive periods in functional brain development: Problems and prospects.

Aural Habilitation Update: The Role of Speech Production Skills of Infants and Children With Hearing Loss

Aural Habilitation Update: The Role of Speech Production Skills of Infants and Children With Hearing Loss

An evolution of communication modalities: very young cochlear implant users who transitioned from sign to speech during the first years of use

The communication modalities used and the articulation and aural-only receptive vocabulary skills were investigated in 19 prelingually profoundly deaf infants who initially utilized Total Communication (TC) and who were implanted between the ages of 12 and 29 months of age. Results revealed the children overwhelmingly used voice-only modality for an expressive task. Additionally, articulation and receptive vocabulary skills approached those of normal hearing peers. Implications of these findings and suggestions for future studies are provided.

Assessment of Prelinguistic Behaviors in Deaf Children: Parents as Collaborators.

This article begins with the rationale for a detailed assessment of prelinguistic behaviors in young deaf children. I used a Hebrew adaptation of the parent questionnaire developed by Camaioni, Caselli, Volterra, and Luchenti (1992) in Italy to collect data on a relatively large heterogeneous Israeli sample of deaf participants: 43 deaf children of hearing parents (19 girls and 24 boys) ranging in age from 8 to 49 months. Results indicated that prelinguistic behaviors in deaf infants resemble only to some extent the theoretical model of prelinguistic communication in hearing infants. Unique interrelationships emerged among pointing and early noncommunicative behaviors, yet no correlation emerged between the use of referential gestures and early words or signs. We analyzed findings with respect to the comparison of prelinguistic behavioral characteristics in hearing and deaf children and the collaboration with parents in assessing the prelinguistic behaviors of their own deaf children.

An Intersubjective Developmental Perspective on Interactions Between Deaf and Hearing Mothers and Their Deaf Infants

Most research into interactions between mothers and their infants with hearing impairments focuses on mothers' and infants' behaviors separately, speculating about the interplay among these behaviors and their effects on child development. In the present article, an intersubjective developmental theory focusing on the development of the "interworld" between deaf and hearing mothers and their deaf infants is used to integrate and interpret the seemingly incoherent research on early mother-deaf child interaction. Inspired by Stern's work (e.g., Stern, 1985), the intersubjective developmental theory distinguishes four stages in the development of intersubjectivity: emerging (birth-2 months), physical (2-8 months), existential (8-13 months), and symbolic (13 months and older), each characterized by a different type of mother-infant interaction. The integration of research findings on early mother-deaf child interaction into these four developmental stages offers new perspectives that can advance research and resolve certain early-intervention issues.

Speech perception skills of deaf infants following cochlear implantation: a first report

Objective: We adapted a behavioral procedure that has been used extensively with normal-hearing (NH) infants, the visual habituation (VH) procedure, to assess deaf infants’ discrimination and attention to speech. Methods: Twenty-four NH 6-month-olds, 24 NH 9-month-olds, and 16 deaf infants at various ages before and following cochlear implantation (CI) were tested in a sound booth on their caregiver's lap in front of a TV monitor. During the habituation phase, each infant was presented with a repeating speech sound (e.g. ‘hop hop hop’) paired with a visual display of a checkerboard pattern on half of the trials (‘sound trials’) and only the visual display on the other half (‘silent trials’). When the infant's looking time decreased and reached a habituation criterion, a test phase began. This consisted of two trials: an ‘old trial’ that was identical to the ‘sound trials’ and a ‘novel trial’ that consisted of a different repeating speech sound (e.g. ‘ahhh’) paired with the same checkerboard pattern. Results: During the habituation phase, NH infants looked significantly longer during the sound trials than during the silent trials. However, deaf infants who had received cochlear implants (CIs) displayed a much weaker preference for the sound trials. On the other hand, both NH infants and deaf infants with CIs attended significantly longer to the visual display during the novel trial than during the old trial, suggesting that they were able to discriminate the speech patterns. Before receiving CIs, deaf infants did not show any preferences. Conclusions: Taken together, the findings suggest that deaf infants who receive CIs are able to detect and discriminate some speech patterns. However, their overall attention to speech sounds may be less than NH infants’. Attention to speech may impact other aspects of speech perception and spoken language development, such as segmenting words from fluent speech and learning novel words. Implications of the effects of early auditory deprivation and age at CI on speech perception and language development are discussed.

Final Syllable Lengthening (FSL) in infant vocalizations.

Final Syllable Lengthening (FSL) has been extensively examined in infant vocalizations in order to determine whether its basis is biological or learned. Findings suggest there may be a U-shaped developmental trajectory for FSL. The present study sought to verify this pattern and to determine whether vocal maturity and deafness influence FSL. Eight normally hearing infants, aged 0;3 to 1;0, and eight deaf infants, aged 0;8 to 4;0, were examined at three levels of prelinguistic vocal development: precanonical, canonical, and postcanonical. FSL was found at all three levels suggesting a biological basis for this phenomenon. Individual variability was, however, considerable. Reduction in the magnitude of FSL across the three sessions provided some support for a downward trend for FSL in infancy. Findings further indicated that auditory deprivation can significantly affect temporal aspects of infant speech production.

Language Development in Deaf Infants Following Cochlear Implantation

Objective—To evaluate the benefits of cochlear implantation in infancy and compare them to those obtained in children implanted at a slightly older age.Material and Methods—Using standard language measurement tools, including the Grammatical Analysis of Elicited Language—Presentence Level (GAEL-P) and the Reynell Developmental Language Scales, progress was documented in a child who received a cochlear implant in infancy and compared to that achieved in children implanted at older ages. A new measurement tool, the Visual Habituation Procedure, was used to document early skills and the results were compared to those obtained in normal-hearing infants.Results—By the age of 2 years the subject implanted in infancy achieved scores on the GAEL-P which were nearly equivalent to those achieved at the age of 51/2 years by children implanted at later ages. Age-equivalent scores on the Reynell Developmental Language Scales were achieved by the subject implanted in infancy and the ability to discriminate speech patterns was demonstrated using the Visual Habituation Procedure.Conclusion—This report demonstrates enhanced language development in an infant who received a cochlear implant at the age of 6 months.

The Use of Visual-Tactile Communication Strategies by Deaf and Hearing Fathers and Mothers of Deaf Infants.

This article presents the results of a study comparing deaf and hearing parents in the use of visual-tactile communication strategies during interaction with their hearing-impaired children between 18 and 24 months of age. The study includes 17 deaf and hard-of-hearing children and 33 parents, covering hearing mothers (n = 12), hearing fathers (n = 11), deaf mothers (n = 5), and deaf fathers (n = 5). The four groups of parents are compared in the use of visual-tactile communication strategies during free play with their children. Overall results show that deaf mothers and deaf fathers differ significantly from hearing parents in the use of a visual communication style adapted to the developmental communication needs and abilities related to the 18- to 24-month age period. The study pays special attention to differences in visual-tactile communication strategies according to hearing status, gender, use of languages, and communication modes.

Projected cost-effectiveness of statewide universal newborn hearing screening.

Early identification of hearing impairment may improve language outcomes and subsequent school and occupational performance of the deaf. Universal newborn hearing screening (UNHS), currently mandated by 32 states, can reduce the median age of identification of hearing impairment from 12 to 18 months to 6 months or less. However, because false-negative tests must be minimized, the prevalence of congenital deafness is low, and screening tests are imperfect, UNHS results in many false-positive results and has a low positive predictive value (PPV). The objective of this study was to evaluate UNHS and selective screening in terms of both short- and long-term benefits, harms, and financial costs and to identify steps in the screening process that could be improved to increase cost-effectiveness. The cost-effectiveness analysis, conducted from the societal perspective, compared the projected outcomes of 1) no newborn hearing screening, 2) selective newborn hearing screening, and 3) UNHS for a hypothetical state birth cohort of 80 000 infants. Probability and cost estimates for the decision model were obtained from published studies, expert opinion, and national and state sources. The main outcomes were incremental cost per infant whose deafness was diagnosed by 6 months, which included only the cost of screening and diagnostic evaluation; and incremental cost per deaf child with normal language, which also included the costs of medical care, education and assistive devices, and lost productivity over the lifetime of the deaf individual. Selective screening identified 62 of the 128 deaf infants in the birth cohort, referred 0.18% of all infants for diagnostic evaluation, and had a PPV of 43%. UNHS identified 116 of the 128 deaf infants, referred 1.6% of all infants, and had a PPV of 8.8%. Our model simulated real-world conditions in which some infants whose deafness is identified at screening do not receive a definitive diagnosis of being deaf before 6 months; and a portion of deaf and hard-of-hearing infants who 1) have false-negative screening test results, 2) are not screened, or 3) fail the hearing screen but are not immediately followed up with diagnostic evaluation nonetheless receive a diagnosis by 6 months of age. In the absence of newborn hearing screening, approximately 30 deaf infants were identified by 6 months of age by passive detection alone at a cost of $69 000. The selective screening protocol, when compared with no newborn hearing screening, resulted in an additional 36 infants whose deafness was diagnosed by 6 months at an additional cost of approximately $600 000, yielding an incremental cost-effectiveness of approximately $16 000 per additional infant whose deafness was diagnosed by 6 months. Compared with selective screening, the UNHS protocol resulted in 33 additional infants whose deafness was diagnosed by 6 months of age at an additional cost of approximately $1.5 million, yielding an incremental cost-effectiveness of approximately $44 000 per additional infant whose deafness was diagnosed by 6 months of age. Increasing the rate of follow-up to diagnostic evaluation from the base-case estimate of 77% to 100% decreased the incremental cost of UNHS to $38 000 per additional infant whose deafness was diagnosed by 6 months. Under the base-case assumptions about lifetime savings that result from normal language with early intervention, UNHS resulted in normal language achievement for more deaf children and was cost saving in the long term compared with both selective screening and no screening. The short-term cost-effectiveness of UNHS is comparable to the cost per case diagnosed of other newborn screening programs and could be improved by increasing the rate of follow-up to diagnostic evaluation after positive screening test results. If early identification results in improved language abilities, lower educational and vocational costs, and increased lifetime productivity, then UNHS has the potential for long-term cost savings compared with selective hearing screening and no screening. To understand the actual long-term economic effects of UNHS, better evidence is needed regarding the impact of early intervention on language outcomes and subsequent changes in educational costs and lifetime productivity.

An original inner ear neuroepithelial degeneration in a deaf Rottweiler puppy

Histopathological investigation was conducted on both inner ears from a 4.5-month-old Rottweiler puppy with electrophysiologically confirmed bilateral deafness. The lesions were restricted to the organ of Corti and spiral ganglion that both displayed severe degenerative changes. The outer hair cells were less affected than the inner hair cells. The number of spiral ganglion neurons was reduced, and remaining neurons were altered. The basal and middle cochlear turns were more affected than the apical one. The vestibules were normal. Immunostaining with calbindin, calretinin, S100A1 and S100A6 polyclonal antisera was helpful in identifying different cell-types in the degenerated cochlea. The early and severe spiral ganglion cell degeneration is an uncommon finding no matter the species. Such lesions bear significance within the frame of cochlear implants technology for deaf infants.

Caring for deaf infants: Some useful pointers

Equal access to high quality education is crucial to the development of deaf children in order for them to acquire the knowledge experience and skills to succeed in life. Eight hundred and forty children are born deaf every year in the UK. An additional one million children will experience temporary hearing loss because of glue ear.

Prelinguistic Gesture Predicts Mastery and Error in the Production of Early Signs

We explore the predictors of early mastery versus error in children's acquisition of American Sign Language. We hypothesize that the most frequent values for a particular parameter in prelinguistic gesture will be the most frequent in early signs and the most likely sources of substitution when signing children make errors. Analyses of data from a longitudinal study of the prelinguistic gestures of five Deaf and five hearing children and a longitudinal study of four Deaf children's early signs have revealed evidence of significant commonalities between prelinguistic gesture and early sign. This apparent continuity between prelinguistic gesture and early sign reflects constraints operating on the infant-in all likelihood, motoric constraints-that seem to persist into the first-word period in both major language modalities. In sign, as in speech, the production of first signs uses building blocks that are available to the prelinguistic child.* 1. PATTERNS IN THE ACQUISITION OF CHILD PHONOLOGY. What are the predictors of early mastery versus early error in child phonology? Can we predict which articulatory features will be successfully rendered by young children when they attempt words or signs? And what factors determine the form of their errors, particularly their substitution patterns? The literature on the acquisition of speech suggests that children in the early word-period will be successful in producing phonetic segments that were frequent in their earlier (and sometimes concurrent) babbling (Locke 1983, MacNeilage et al. 1997). In this article, we explore a sizable corpus of early signs produced on videotape by four Deaf children of Deaf parents; their ages ranged from 5 to 17 months over the course of the study.1 These children were acquiring American Sign Language (ASL) as their first language. To develop predictions about which formational aspects of signs would be successfully produced by these children, we turned to data on prelinguistic gestures produced by two other groups of children. We use the term PRELINGUISTIC GESTURE to refer to the set of nonlinguistic gestures that are produced prior to the onset of language production and/or concurrently with early words or signs. Prelinguistic gestures were identified in longitudinally collected videotapes from five hearing children with no sign exposure and five Deaf children of Deaf signing parents. The ages of the infants who contributed prelinguistic gesture data ranged from 7 to 13 months. We test two broad hypotheses: (1) on any parameter of sign formation, the most frequent values in prelinguistic gesture will also be the most frequent in early signs; and (2) on any parameter of sign formation, the most frequent values in prelinguistic gesture will be the most likely sources of substitution when young signing children make errors. The fact that we have data on prelinguistic gestures from Deaf infants reared in signing families and from hearing infants with no sign exposure will give us insight into the source of any articulatory preferences that appear in prelinguistic gesture and in early signing. Articulatory preferences that are identified in the prelinguistic

Babbling and the lack of auditory speech perception: a matter of coordination?

This paper concentrates on the question whether and where the lack of auditory perception can be traced in the early sound productions of deaf infants. A sensorimotor description system based on movements in the phonatory and articulatory speech production systems was developed to classify early infant vocalizations. Canonical babbling is a strong cue in the normal speech developmental process. Therefore the main question in this work was why deaf infants do not start to babble in their first year of life like normally hearing children do. Detailed analyses of early vocalizations of deaf and hearing infants revealed that auditory feedback is needed to lead to coordination of movements of the phonatory and the articulatory system, and that this coordination capacity is a prerequisite for the development of normal speech production.

How do deaf infants attain first signs?

In this study the development and alternation of nonreferential gestures were examined longitudinally in terms of the acquisition of Japanese sign language. Parent–child free‐play sessions in their home were videotaped at every monthly visit. Hand activities produced by two deaf infants of deaf parents are described and analyzed. Nonreferential gestures were observed frequently just before the occurrences of the first signs. They consisted of many rhythmic and repetitious movements. Nonreferential gestures became more complex and the number of them also increased as infants grew up. The comparison of nonreferential gestures and first signs revealed the continuity between them in terms of movements. In conclusion, nonreferential gestures are equivalent to a manual analog of vocal babbling.

Beyond parent education: the impact of extended family dynamics in deaf education.

The impact of childhood deafness on family dynamics, with particular attention given to the influence and role of grandparents, is discussed. Models for the successful involvement of parents in the education of deaf children are already in place and can be applied to extended family, especially grandparents, with promising results. An informal questionnaire focusing on grandparents' support, involving 10 hearing parents of deaf infants and preschool children, is reviewed.