Derek M. Houston

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.

Language skills of profoundly deaf children who received cochlear implants under 12 months of age: a preliminary study

Conclusion. This study demonstrated that children who receive a cochlear implant below the age of 2 years obtain higher mean receptive and expressive language scores than children implanted over the age of 2 years. Objective. The purpose of this study was to compare the receptive and expressive language skills of children who received a cochlear implant before 1 year of age to the language skills of children who received an implant between 1 and 3 years of age. Subjects and methods. Standardized language measures, the Reynell Developmental Language Scale (RDLS) and the Preschool Language Scale (PLS), were used to assess the receptive and expressive language skills of 91 children who received an implant before their third birthday. Results. The mean receptive and expressive language scores for the RDLS and the PLS were slightly higher for the children who were implanted below the age of 2 years compared with the children who were implanted over 2 years old. For the PLS, both the receptive and expressive mean standard scores decreased with increasing age at implantation.

Word Learning in Infant- and Adult-Directed Speech

Infant-directed speech (IDS), compared with adult-directed speech (ADS), is characterized by a slower rate, a higher fundamental frequency, greater pitch variations, longer pauses, repetitive intonational structures, and shorter sentences. Despite studies on the properties of IDS, there is no direct demonstration of its effects for word learning in infants. This study examined whether 21- and 27-month-old children learned novel words better in IDS than in ADS. Two major findings emerged. First, 21-month-olds reliably learned words only in the IDS condition, although children with relatively larger vocabulary than their peers learned in the ADS condition as well. Second, 27-month-olds reliably learned the words in the ADS condition. These results support the implicitly held assumption that IDS does in fact facilitate word mapping at the start of lexical acquisition and that its influence wanes as language development proceeds.

Effects of Early Auditory Experience on Word Learning and Speech Perception in Deaf Children With Cochlear Implants: Implications for Sensitive Periods of Language Development

Hypothesis: That early word learning and speech perception skills have different sensitive periods and that very early implantation may affect later vocabulary outcomes more than speech perception outcomes. Background: Several studies have found that deaf children who receive cochlear implants before 3 years of age tend to have better speech perception outcomes than children implanted later. Recent studies have not found age-at-implantation effects on speech perception or central auditory processing among children implanted younger than 2 years, suggesting that there may be a sensitive period for speech perception skills that closes by around 3 years of age. There has been very little work investigating possible sensitive periods for other language skills, such as the ability to learn words. Recent work suggests the possibility that the development of word-learning skills may have an earlier sensitive period than the development of speech perception skills. Methods: Assess speech perception and vocabulary outcomes in children implanted before 13 months of age and in children implanted between 16 and 23 months of age. Results: Children implanted during the first year of life had better vocabulary outcomes than children implanted during the second year of life. However, earlier implanted children did not show better speech perception outcomes than later implanted children. Conclusion: There may be an earlier sensitive period for developing the ability to associate the sound patterns of words to their referents than for developing speech perception and central auditory processing skills.

Word learning in deaf children with cochlear implants: effects of early auditory experience

Word-learning skills were tested in normal-hearing 12- to 40-month-olds and in deaf 22- to 40-month-olds 12 to 18 months after cochlear implantation. Using the Intermodal Preferential Looking Paradigm (IPLP), children were tested for their ability to learn two novel-word/novel-object pairings. Normal-hearing children demonstrated learning on this task at approximately 18 months of age and older. For deaf children, performance on this task was significantly correlated with early auditory experience: Children whose cochlear implants were switched on by 14 months of age or who had relatively more hearing before implantation demonstrated learning in this task, but later implanted profoundly deaf children did not. Performance on this task also correlated with later measures of vocabulary size. Taken together, these findings suggest that early auditory experience facilitates word learning and that the IPLP may be useful for identifying children who may be at high risk for poor vocabulary development.

Cochlear Implantation in Deaf Infants

Objectives: 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.

English-learning infants' segmentation of trisyllabic words from fluent speech

Recent investigations with English-learning infants have shown that the rhythmic properties of English influence how infants segment fluent speech. In particular, 7.5-month-old infants have been shown to extract bisyllabic words that conform to the predominant strong/weak stress pattern of English but not weak/strong words. The present series of studies examined whether English-learning 7.5-month-olds’ segmentation abilities are limited to extracting strong/weak bisyllables or whether they are able to segment longer strings, such as trisyllables (strong/weak/strong). The results indicated that infants can segment trisyllabic words from fluent speech but only when the first syllable receives primary stress (e.g., cantaloupe). When primary stress falls on the last syllable (e.g., cavalier), infants segment only the final stressed syllables. Overall, the findings suggest that 7.5-month-old English-learning infants are able to segment longer strings, and that they use stress as a major cue in segmentation. English-learners appear to equate strong syllables with word onsets only when the strong syllable receives primary stress.

Surgical management of obstructive sleep apnea in infants and young toddlers

Objective: Review surgical management of obstructive sleep apnea (OSA) in infants and young toddlers compared with a medically treated group. Study Design: Case series with chart review of children younger than 24 months treated at a tertiary pediatric hospital between 2000 and 2005. Subjects and Methods: Surgical treatment included adenotonsillectomy, adenoidectomy, and tonsillectomy. Polysomnography results, comorbidities, and major complications were recorded. The change in apnea-hypopnea index (AHI) before and after treatment was analyzed. Logistic regression analysis reviewed effects of comorbidities and OSA severity on complications. Results: A total of 73 children met inclusion criteria. The surgical treatment group (AHI) improved posttreatment: mean AHI change was 9.6 (95% CI, 5.8-13.4). The medical treatment group did not improve posttreatment: mean AHI change was −3.0 (95% CI, −15.1 to 9.1). The difference in AHI change between surgical and medical groups was 12.56 (95% CI, 2.7-22.4). An independent t test found this difference to be statistically significant (P = 0.01). Eleven (18%) patients suffered significant postoperative surgical complications; 55 surgical patients and 8 medical patients had comorbidities. There were no long-term morbidities or mortalities. Conclusions: AHI in the surgically treated group significantly improved. The complication rate for a tertiary pediatric hospital population that included patients with multiple comorbidities was acceptable.

The ear is connected to the brain: some new directions in the study of children with cochlear implants at Indiana University.

Since the early 1980s, the DeVault Otologic Research Laboratory at the Indiana University School of Medicine has been on the forefront of research on speech and language outcomes in children with cochlear implants. This paper highlights work over the last decade that has moved beyond collecting speech and language outcome measures to focus more on investigating the underlying cognitive, social, and linguistic skills that predict speech and language outcomes. This recent work reflects our growing appreciation that early auditory deprivation can affect more than hearing and speech perception. The new directions include research on attention to speech, word learning, phonological development, social development, and neurocognitive processes. We have also expanded our subject populations to include infants and children with additional disabilities.

Language processing in children with cochlear implants: A preliminary report on lexical access for production and comprehension

In this plenary paper, we present a review of language research in children with cochlear implants along with an outline of a 5-year project designed to examine the lexical access for production and recognition. The project will use auditory priming, picture naming with auditory or visual interfering stimuli (Picture–Word Interference and Picture–Picture Interference, respectively) and eye tracking paradigms to examine the roles of semantic and various phonological factors. Preliminary data are presented from auditory priming, picture–word interference and picture–picture interference tasks. The emergence of group difference is briefly discussed.