Mark Seeto

Outcomes of early- and late-identified children at 3 years of age: findings from a prospective population-based study.

Objective: To address the question of whether, on a population level, early detection and amplification improve outcomes of children with hearing impairment. Design: All families of children who were born between 2002 and 2007, and who presented for hearing services below 3 years of age at Australian Hearing pediatric centers in New South Wales, Victoria, and Southern Queensland were invited to participate in a prospective study on outcomes. Children’s speech, language, functional, and social outcomes were assessed at 3 years of age, using a battery of age-appropriate tests. Demographic information relating to the child, family, and educational intervention was solicited through the use of custom-designed questionnaires. Audiological data were collected from the national database of Australian Hearing and records held at educational intervention agencies for children. Regression analysis was used to investigate the effects of each of 15 predictor variables, including age of amplification, on outcomes. Results: Four hundred and fifty-one children enrolled in the study, 56% of whom received their first hearing aid fitting before 6 months of age. On the basis of clinical records, 44 children (10%) were diagnosed with auditory neuropathy spectrum disorder. There were 107 children (24%) reported to have additional disabilities. At 3 years of age, 317 children (70%) were hearing aid users and 134 children (30%) used cochlear implants. On the basis of parent reports, about 71% used an aural/oral mode of communication, and about 79% used English as the spoken language at home. Children’s performance scores on standardized tests administered at 3 years of age were used in a factor analysis to derive a global development factor score. On average, the global score of hearing-impaired children was more than 1 SD below the mean of normal-hearing children at the same age. Regression analysis revealed that five factors, including female gender, absence of additional disabilities, less severe hearing loss, higher maternal education, and (for children with cochlear implants) earlier age of switch-on were associated with better outcomes at the 5% significance level. Whereas the effect of age of hearing aid fitting on child outcomes was weak, a younger age at cochlear implant switch-on was significantly associated with better outcomes for children with cochlear implants at 3 years of age. Conclusions: Fifty-six percent of the 451 children were fitted with hearing aids before 6 months of age. At 3 years of age, 134 children used cochlear implants and the remaining children used hearing aids. On average, outcomes were well below population norms. Significant predictors of child outcomes include: presence/absence of additional disabilities, severity of hearing loss, gender, maternal education, together with age of switch-on for children with cochlear implants.

The effects of hearing impairment and aging on spatial processing.

Objectives: Difficulty in understanding speech in background noise is frequently reported by hearing-impaired people despite well-fitted amplification. Understanding speech in the presence of background noise involves segregating the various auditory stimuli into distinct streams using cues such as pitch characteristics, spatial location of speakers, and contextual information. One possible cause of listening difficulties in noise is reduced spatial-processing ability. Previous attempts to investigate spatial processing in hearing-impaired people have often been confounded by inadequate stimulus audibility. The present research aimed to investigate the effects of hearing impairment and aging on spatial-processing ability. The effect of cognitive ability on spatial processing was also explored. In addition, the relationship between spatial-processing ability and self-report measures of listening difficulty was examined to investigate how much effect spatial-processing ability has in real-world situations. Design: Eighty participants aged between 7 and 89 years took part in the study. Participants’ hearing thresholds ranged from within normal limits to a moderately severe sensorineural hearing loss. All participants had English as their first language and no reported learning disabilities. The study sample included both hearing aid users and non–hearing aid users. Spatial-processing ability was assessed with a modified version of the Listening in Spatialized Noise-Sentences test (LiSN-S). The LiSN-S was modified to incorporate a prescribed gain amplifier that amplified the target and distracting stimulus according to the National Acoustic Laboratories-Revised Profound (NAL-RP) prescription. In addition, participants aged 18 years and above completed the Neurobehavioral Cognitive Status examination and the Speech, Spatial and Qualities questionnaire. Participants aged under 18 years completed the Listening Inventory for Education questionnaire. Results: Spatial-processing ability, as measured by the spatial advantage measure of the LiSN-S, was negatively affected by hearing impairment. Aging was not significantly correlated with spatial-processing ability. No significant relationship was found between cognitive ability and spatial processing. Self-reported listening difficulty in children, as measured with the Listening Inventory for Education, and spatial-processing ability were not correlated. Self-reported listening difficulty in adults, as measured by the Speech, Spatial and Qualities questionnaire, was significantly correlated with spatial-processing ability. Conclusions: All hearing-impaired people will have a spatial processing deficit of some degree. This should be given due consideration when counseling patients in regard to realistic expectations of how they will perform in background noise. Further research is required into potential remediation for spatial-processing deficits and the cause of these deficits.

Outcomes of 3-Year-Old Children With Hearing Loss and Different Types of Additional Disabilities

This research investigated the speech, language, and functional auditory outcomes of 119 3-year-old children with hearing loss and additional disabilities. Outcomes were evaluated using direct assessment and caregiver report. Multiple regressions revealed that type of additional disability and level of maternal education were significant predictors of language outcomes. Poorer outcomes were achieved in a combined group of children with autism, cerebral palsy, and/or developmental delay (DD) (Group A), compared with children with vision or speech output impairments, syndromes not entailing DD, or medical disorders (Group B). Better outcomes were associated with higher levels of maternal education. The association between better language outcomes and earlier cochlear implant switch-on approached significance. Further regression analyses were conducted separately for children with different types of additional disabilities. Level of maternal education was the only significant predictor of outcomes for Group A children, whereas degree of hearing loss was the strongest predictor for children in Group B. The findings highlight the variable impact that different types of additional disabilities can have on language development in children with hearing loss.

Etiology and Audiological Outcomes at 3 Years for 364 Children in Australia

Hearing loss is an etiologically heterogeneous trait with differences in the age of onset, severity and site of lesion. It is caused by a combination of genetic and/or environmental factors. A longitudinal study to examine the efficacy of early intervention for improving child outcomes is ongoing in Australia. To determine the cause of hearing loss in these children we undertook molecular testing of perinatal “Guthrie” blood spots of children whose hearing loss was either detected via newborn hearing screening or detected later in infancy. We analyzed the GJB2 and SLC26A4 genes for the presence of mutations, screened for the mitochondrial DNA (mtDNA) A1555G mutation, and screened for congenital CMV infection in DNA isolated from dried newborn blood spots. Results were obtained from 364 children. We established etiology for 60% of children. One or two known GJB2 mutations were present in 82 children. Twenty-four children had one or two known SLC26A4 mutations. GJB2 or SLC26A4 changes with unknown consequences on hearing were found in 32 children. The A1555G mutation was found in one child, and CMV infection was detected in 28 children. Auditory neuropathy spectrum disorder was confirmed in 26 children whose DNA evaluations were negative. A secondary objective was to investigate the relationship between etiology and audiological outcomes over the first 3 years of life. Regression analysis was used to investigate the relationship between hearing levels and etiology. Data analysis does not support the existence of differential effects of etiology on degree of hearing loss or on progressiveness of hearing loss.

Impact of the presence of auditory neuropathy spectrum disorder (ANSD) on outcomes of children at three years of age

Abstract Objective: To determine the influence of the presence of auditory neuropathy spectrum disorder (ANSD) on speech, language, and psycho-social development of children at three years of age. Design: A population-based, longitudinal study was performed on outcomes of children with hearing impairment (LOCHI) in Australia. The demographic characteristics of the children were described, and their developmental outcomes were evaluated at three years of age. Performance of children with ANSD was compared with that of children without ANSD in the LOCHI study. Study sample: There were 47 children with ANSD in the study sample. Results: Sixty-four percent of children with ANSD have hearing sensitivity loss ranging from mild to severe degree, and the remaining have profound hearing loss. At three years, 27 children used hearing aids, 19 used cochlear implants, and one child did not use any hearing device. Thirty percent of children have disabilities in addition to hearing loss. On average, there were no significant differences in performance level between children with and without ANSD. Also, the variability of scores was not significantly different between the two groups. Conclusions: There was no significant difference in performance levels or variability between children with and without ANSD, both for children who use hearing aids, and children who use cochlear implants.

Age at Intervention for Permanent Hearing Loss and 5-Year Language Outcomes

The benefit of early age at intervention for language development of children with PCHL increases with the degree of hearing loss. OBJECTIVES: Universal newborn hearing screening has been implemented to detect permanent childhood hearing loss (PCHL) early, with the ultimate goal of improving outcomes through early treatment. However, there is disagreement between studies on the size of this benefit and in some cases whether it is significantly different from 0. There have been no studies of sufficient size in which researchers have determined reliably whether the effect varies with degree of PCHL. We aimed to explore how intervention timing influences 5-year language in children with PCHL. METHODS: Via a prospective study of 350 children, we used standard multiple regression analyses to investigate the effect of age at intervention or hearing screening on language outcomes after allowing for the effects of nonverbal IQ, degree of PCHL, sex, birth weight, maternal education, additional disabilities, and communication mode. RESULTS: The benefit of early intervention for language development increased as hearing loss increased. Children whose amplification started at age 24 months had poorer language than those whose amplification started at 3 months. The difference was larger for 70-dB HL (−11.8 score points; 95% confidence interval [95% CI]: −18.7 to −4.8) than for 50-dB HL (−6.8; 95% CI: −10.8 to −2.8). Children who received cochlear implants at 24 months had poorer language than those implanted at 6 months (−21.4; 95% CI: −33.8 to −9.0). There was no significant effect of screening on outcomes. CONCLUSIONS: Early intervention improves language outcomes, thereby lending support to streamlining clinical pathways to ensure early amplification and cochlear implantation after diagnosis.

Language and speech perception of young children with bimodal fitting or bilateral cochlear implants

Abstract Objectives This paper compares language development and speech perception of children with bimodal fitting (a cochlear implant in one ear and a hearing aid in the opposite ear) or bilateral cochlear implantation. Methods Participants were children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment study. Language development was assessed at 3 years of age using standardized tests. Speech perception was evaluated at 5 years of age. Speech was presented from a frontal loudspeaker, and babble noise was presented either from the front or from both sides. Results On average, there was no significant difference in language outcomes between 44 children with bimodal fitting and 49 children with bilateral cochlear implants; after controlling for a range of demographic variables. Earlier age at cochlear implant activation was associated with better outcomes. Speech perception in noise was not significantly different between children with bimodal fitting and those with bilateral cochlear implants. Compared to normal-hearing children, children with cochlear implants required a better signal-to-noise ratio to perform at the same level, but demonstrated spatial release from masking of a similar magnitude. Conclusions This population-based study found that language scores for children with bilateral implants were higher than those with bimodal fitting or those with unilateral implants, but neither reached significance level.

A randomized controlled trial of nonlinear frequency compression versus conventional processing in hearing aids: Speech and language of children at three years of age

Abstract Objective: To determine the effect of nonlinear frequency compression (NLFC) on childrens development of speech and language at three years of age. Design: A randomized controlled trial was conducted as part of the population-based longitudinal study on outcomes of children with hearing impairment (LOCHI). Participants were randomly assigned to fitting with NLFC (Phonak Naida V SP or UP) or with conventional processing in hearing aids, prescribed by using either the NAL or the DSL formula. Standardized tests of speech production, receptive and expressive language were administered, and parent ratings were collected. All assessments were double-blinded. Study sample: Participants were 44 of the 450 children in the LOCHI cohort. Results: Compared to children using conventional processing, receptive and expressive language was higher but receptive vocabulary and consonant articulation scores were lower for children who use NLFC. There was increased substitution of affricates by fricatives for children using NLFC, compared to children using conventional amplification. After allowing for the effect of multiple demographic variables, the difference in global language scores between groups was not significant (effect: 0.8 [95% confidence interval: − 6.7, 8.3]). Conclusions: There is insufficient evidence to indicate a difference in language ability between children using NLFC and those using conventional amplification.

Evaluation of the self-fitting process with a commercially available hearing aid

Background: Hearing aids and personal sound amplification products that are designed to be self‐fitted by the user at home are becoming increasingly available in the online marketplace. While these devices are often marketed as a low‐cost alternative to traditional hearing health‐care, little is known about peoples ability to successfully use and manage them. Previous research into the individual components of a simulated self‐fitting procedure has been undertaken, but no study has evaluated performance of the procedure as a whole using a commercial product. Purpose: To evaluate the ability of a group of adults with a hearing loss to set up a pair of commercially available self‐fitting hearing aids for their own use and to investigate factors associated with a successful outcome. Research Design: An interventional study that used regression analysis to identify potential contributors to the outcome. Study Sample: Forty adults with mild to moderately severe hearing loss participated in the study: 20 current hearing aid users (the “experienced” group) and 20 with no previous amplification experience (the “new” group). Twenty‐four participants attended with partners, who were present to offer assistance with the study task as needed. Data Collection and Analysis: Participants followed a set of written, illustrated instructions to perform a multistep self‐fitting procedure with a commercially available self‐fitting hearing aid, with optional assistance from a lay partner. Standardized measures of cognitive function, health literacy, locus of control, hearing aid self‐efficacy, and manual dexterity were collected. Statistical analysis was performed to examine the proportion of participants in each group who successfully performed the self‐fitting procedure, factors that predicted successful completion of the task, and the contributions of partners to the outcome. Results: Fifty‐five percent of participants were able to successfully perform the self‐fitting procedure. Although the same success rate was observed for both experienced and new participants, the majority of the errors relating to the hearing test and the fine‐tuning tasks were made by the experienced participants, while all of the errors associated with physically customizing the hearing aids and most of the insertion errors were made by the new participants. Although the majority of partners assisted in the self‐fitting task, their contributions did not significantly influence the outcome. Further, no characteristic or combination of characteristics reliably predicted which participants would be successful at the self‐fitting task. Conclusions: Although the majority of participants were able to complete the self‐fitting task without error, the provision of knowledgeable support by trained personnel, rather than a fellow layperson, would most certainly increase the proportion of users who are able to achieve success. Refinements to the instructions and the physical design of the hearing aid may also serve to improve the success rate. Further evaluation of the range of self‐fitting hearing aids that are now on the market should be undertaken.

Factors Affecting Psychosocial and Motor Development in 3-Year-Old Children Who Are Deaf or Hard of Hearing

Previous research has shown an association between childrens development of psychosocial and motor skills. This study evaluated the development of these skills in 301 three-year-old deaf and hard of hearing children (M: 37.8 months) and considered a range of possible predictors including gender, birth weight, age at first fitting with hearing devices, hearing device used, presence of additional disabilities, severity of hearing loss, maternal education, socio-economic status (SES), language ability, and communication mode. Caregivers reported on childrens development using the Child Development Inventory (CDI). On average, both psychosocial and motor development quotients were within the typical range for hearing children, with large individual differences. There was a positive correlation between language ability and both social and motor development, and also between social and motor development. Age at first fitting of hearing aids (as an indicator of age at identification of hearing loss), SES, degree of hearing loss, and maternal education were not significant predictors of social skill or motor development, whereas presence of additional disabilities and birth weight were. Girls performed better than boys on all but the Gross Motor subscale of the CDI. Children with hearing aids tended to perform better than those with cochlear implants on the Gross Motor subscale.