Hearing aid fitting and developmental outcomes of children fit according to either the NAL or DSL prescription: fit-to-target, audibility, speech and language abilities

Correction Factor Evaluation and Between-System Comparison of Behavioral Threshold Predictions From Auditory Brainstem Response Measures in Infants

PURPOSE

Auditory brainstem response (ABR) thresholds are corrected to estimate behavioral thresholds in infants. Corrections were validated, and a comparison of behavioral threshold estimates between systems was conducted to inform equipment transition and protocols in Ontario, Canada.

METHOD

In Study 1, a retrospective file review was conducted. ABR threshold estimates from 84 infants with hearing loss were compared to behavioral thresholds to validate the accuracy of the ABR corrections applied in the Ontario Infant Hearing Program since 2016. Study 2 examined the precision of two different ABR systems to estimate thresholds in 37 adult and 105 infant ears.

RESULTS

Corrected ABR thresholds predicted behavioral thresholds in infants to within 1.77 dB (range of mean values across frequency: 1.18-2.26 dB) on average. The average differences decreased across frequency to 0.6 dB (range: 0.14 to -1.23) when ear canal acoustics were accounted for. The average between-system difference in ABR threshold estimates was 2.40 dB (range: 1.18-2.26).

CONCLUSIONS

ABR correction factors used in Ontario's Infant Hearing Program provide accurate predictions of behavioral thresholds in infants with hearing loss. When calibration and collection parameters are similar between different ABR systems, threshold estimates are comparable and no further adjustment to correction factors was required.

Investigation of hearing aid fitting according to the national acoustic laboratories' prescription for non-linear hearing aids and the desired sensation level methods in Japanese speakers: a crossover-controlled trial

OBJECTIVE

Some studies have directly compared the National Acoustic Laboratories' prescription for non-linear hearing aids (HAs) version 2 (NAL-NL2) and Desired Sensation Level for non-linear HAs version 5 (DSLv5), although none were performed in Japan. As the Japanese language is a tonal language that has different linguistic characteristics than those of the studied languages, we compared the outcomes of the NAL-NL2 and DSLv5 in hearing-impaired Japanese participants.

METHODS

A crossover-controlled trial was conducted on 18 first-time HA users with bilateral moderate sensorineural hearing loss. Participants wore HAs adjusted with each prescriptive method for four weeks. The prescriptions were assessed using speech discrimination testing and the abbreviated profile of hearing aid benefit (APHAB). Consequently, participants were asked to select their preferred prescription and determine which was better for "listening to a conversation" and when "noisy."

RESULTS

The mean DSLv5 real ear insertion gain for an input level of 65 dB sound pressure level (SPL) was higher than that of the NAL-NL2 at 250 and 500 Hz. The average speech discrimination score was 78 ± 14% at a 65-dB SPL and 75 ± 17% at an 80-dB SPL for the NAL-NL2, and 79 ± 11% at a 65-dB SPL and 77 ± 17% at an 80-dB SPL for the DSLv5. These differences were not significant. No significant differences were observed in APHAB subscale scores between the two prescription methods. Ultimately, 11 (61%) and 7 (39%) participants preferred the NAL-NL2 and DSLv5, respectively, with no significant differences.

CONCLUSION

Although the gain of the NAL-NL2 is smaller than that of the DSLv5, both had the same hearing effect. Therefore, the NAL-NL2 may be more useful than the DSLv5 in Japanese.

Speech Discrimination in Infancy Predicts Language Outcomes at 30 Months for Both Children with Normal Hearing and Those with Hearing Differences

BACKGROUND

Speech discrimination assessments are used to validate amplification fittings of older children who are hard of hearing (CHH). Unfortunately, speech discrimination is not assessed clinically ≤24 months and in turn no studies have investigated the relationship between speech discrimination during infancy and later language development among CHH.

OBJECTIVE

To examine the relationship between an individual infant's speech discrimination measured at 9 months and their expressive/receptive spoken language at 30 months for children with normal hearing (CNH) and CHH.

METHODS

Behavioral speech discrimination was assessed at 9 months and language assessments were conducted at 16, 24, and 30 months using a parent questionnaire, and at 30 months using the Mullen Scales of Early Learning among 90 infants (49 CNH; 41 CHH).

RESULTS

Conditioned Head Turn (CHT) performance for /a-i/ significantly predicted expressive and receptive language at 30 months across both groups. Parental questionnaires were also predictive of later language ability. No significant differences in speech discrimination or language outcomes between CNH and CHH were found.

CONCLUSIONS

This is the first study to document a positive relationship between infant speech discrimination and later language abilities in both early-identified CHH and CNH.

Optimising hearing aid output to paediatric prescriptive targets improves outcomes in children

OBJECTIVE

This study examined the accuracy of hearing aid output to DSL v5.0 Child targets in a group of children who wear hearing aids, and the impact on their auditory outcomes.

DESIGN

For each participant, the output of the initial hearing aid fitting was compared to DSL v5.0 Child prescriptive targets and again after the fitting was adjusted using coupler-based verification and RECD measures. Outcomes for initial and adjusted fittings were examined using the Speech Intelligibility Index (SII), Parent's Evaluation of Aural/Oral Performance of Children (PEACH) rating scale, and speech perception tests in quiet and noise.

STUDY SAMPLE

Sixty-eight children aged 3 months to 17 years with moderate to profound hearing loss participated in the study.

RESULTS

Fit-to-targets improved significantly after hearing aids were adjusted to match targets to within 5 dB RMSE. Adjusted hearing aids provided increased aided audibility compared to initial fittings and resulted in improved speech perception scores and parent-reported hearing performance. Fifty percent of the children aged 6 to 17 years preferred their adjusted fitting compared to 10% who preferred their initial fitting.

CONCLUSIONS

Improvement in fit-to-target to a validated paediatric prescriptive formula using best practice procedures can result in improved auditory outcomes and possible self-reported satisfaction.

Meeting the Best Practice for Hearing Aid Verification in Children: Challenges and Future Directions

Purpose This study examined the current pediatric amplification practice with an emphasis on hearing aid verification using probe microphone measurement (PMM), among audiologists in Klang Valley, Malaysia. Frequency of practice, access to PMM system, practiced protocols, barriers, and perception toward the benefits of PMM were identified through a survey. Method A questionnaire was distributed to and filled in by the audiologists who provided pediatric amplification service in Klang Valley, Malaysia. One hundred eight (N = 108) audiologists, composed of 90.3% women and 9.7% men (age range: 23-48 years), participated in the survey. Results PMM was not a clinical routine practiced by a majority of the audiologists, despite its recognition as the best clinical practice that should be incorporated into protocols for fitting hearing aids in children. Variations in practice existed warranting further steps to improve the current practice for children with hearing impairment. The lack of access to PMM equipment was 1 major barrier for the audiologists to practice real-ear verification. Practitioners' characteristics such as time constraints, low confidence, and knowledge levels were also identified as barriers that impede the uptake of the evidence-based practice. Conclusions The implementation of PMM in clinical practice remains a challenge to the audiology profession. A knowledge-transfer approach that takes into consideration the barriers and involves effective collaboration or engagement between the knowledge providers and potential stakeholders is required to promote the clinical application of evidence-based best practice.

Early Cognitive Predictors of 9-Year-Old Spoken Language in Children With Mild to Severe Hearing Loss Using Hearing Aids

This study examined the extent to which cognitive ability at 5 years of age predicted language development from 5 to 9 years of age in a population-based sample of children with hearing loss who participated in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study. The developmental outcomes of 81 children with hearing loss were evaluated at 5 and 9 years of age. Hearing loss ranged from mild to severe degrees, and all participants used hearing aids. They all used spoken language as the primary mode of communication and education. Nine-year-old language was assessed using the Clinical Evaluation of Language Fundamentals – 4th edition (CELF-4), the Peabody Picture Vocabulary Test – 4th edition (PPVT-4), and the Expressive Vocabulary Test – 2nd edition (EVT-2). Multiple regression analyses were conducted to examine the extent to which children’s scores on these standardized assessments were predicted by their cognitive ability (non-verbal IQ and verbal working memory) measured at 5 years of age. The influence of early language scores at 5 years and a range of demographic characteristics on language scores at 9 years of age was evaluated. We found that 5-year-old digit span score was a significant predictor of receptive and expressive language, but not receptive or expressive vocabulary, at 9 years of age. Also, 5-year-old non-word repetition test score was a significant predictor of only expressive language and vocabulary, but not receptive language or vocabulary at 9 years of age. After allowing for the effects of non-verbal IQ and 5-year-old receptive vocabulary, early digit span score (but not non-word repetition score) was a significant predictor of expressive and receptive language scores at 9 years of age. The findings shed light on the unique role of early verbal working memory in predicting the development of receptive and expressive language skills and vocabulary skills in children who use hearing aids.

Non-implantable Artificial Hearing Technology

A hearing aid is a sound-amplifying device used for aiding hearing-impaired individuals and compensating hearing loss. With the development of science and technology, tremendous strides have been made in hearing aid technology. The history of hearing aids can be divided into five eras: acoustic era, carbon era, vacuum tube era, transistor and integrated circuit era, and digital era. It mainly comprises microphone, amplifier, receiver, battery, volume and tone control buttons, and other electroacoustic components, which can be classified into following types: pocket hearing aids, BTE hearing aids, ITE hearing aids, ITE hearing aids, completely/invisible-in-canal hearing aids (CIC and IIC), and other types. Of them, one bone-anchored hearing aid (BAHA) softband is mainly applicable to children under 5 years old who cannot wear bone-anchored hearing aids in congenital bilateral external auditory canal occlusion. BAHA system comprises three components: a titanium implant (fixture screw), an external abutment (bridging screw), and a sound processor consisting of a microphone and a transducer. The following procedures are included in hearing aid fitting: medical history collection, trial, fitting, ear sample taking, hearing aid refitting, evaluation, practical instruction, and follow-up care. Children should be helped to select hearing aid as early as possible, and for those with congenital hearing loss or prelingual deafness, it can be added assessment of speech development while preventing the child from swallowing hearing aids or batteries by mistake. Speech recognition score (SRS) test is very important in elderly patients, because the speech hearing and pure-tone hearing of presbycusis are often inconsistent. After the hearing aid is selected, the effect evaluation and related rehabilitation should be carried out timely.

Factors influencing speech perception in noise for 5-year-old children using hearing aids or cochlear implants

OBJECTIVE

We investigated the factors influencing speech perception in babble for 5-year-old children with hearing loss who were using hearing aids (HAs) or cochlear implants (CIs).

DESIGN

Speech reception thresholds (SRTs) for 50% correct identification were measured in two conditions - speech collocated with babble, and speech with spatially separated babble. The difference in SRTs between the two conditions give a measure of binaural unmasking, commonly known as spatial release from masking (SRM). Multiple linear regression analyses were conducted to examine the influence of a range of demographic factors on outcomes.

STUDY SAMPLE

Participants were 252 children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study.

RESULTS

Children using HAs or CIs required a better signal-to-noise ratio to achieve the same level of performance as their normal-hearing peers but demonstrated SRM of a similar magnitude. For children using HAs, speech perception was significantly influenced by cognitive and language abilities. For children using CIs, age at CI activation and language ability were significant predictors of speech perception outcomes.

CONCLUSIONS

Speech perception in children with hearing loss can be enhanced by improving their language abilities. Early age at cochlear implantation was also associated with better outcomes.

Learning from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study: summary of 5-year findings and implications

OBJECTIVE

This article summarises findings of the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study, and discusses implications of the findings for research and clinical practice.

DESIGN

A population-based study on outcomes of children with hearing loss. Evaluations were conducted at five years of age.

STUDY SAMPLE

Participants were 470 children born with hearing loss between 2002 and 2007 in New South Wales, Victoria and Queensland in Australia, and who first received amplification or cochlear implantation by three years of age.

RESULTS

The earlier hearing aids or cochlear implants were fitted, the better the speech, language and functional performance outcomes. Better speech perception was also associated with better language and higher cognitive abilities. Better psychosocial development was associated with better language and functional performance. Higher maternal education level was also associated with better outcomes. Qualitative analyses of parental perspectives revealed the multiple facets of their involvement in intervention.

CONCLUSIONS

The LOCHI study has shown that early fitting of hearing devices is key to achieving better speech, language and functional performance outcomes for children with hearing loss. The findings are discussed in relation to changes in clinical practice and directions for future research.

Spoken language and everyday functioning in 5-year-old children using hearing aids or cochlear implants

OBJECTIVE

This study investigated the factors influencing 5-year language, speech and everyday functioning of children with congenital hearing loss.

DESIGN

Standardised tests including PLS-4, PPVT-4 and DEAP were directly administered to children. Parent reports on language (CDI) and everyday functioning (PEACH) were collected. Regression analyses were conducted to examine the influence of a range of demographic variables on outcomes.

STUDY SAMPLE

Participants were 339 children enrolled in the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study.

RESULTS

Children's average receptive and expressive language scores were approximately 1 SD below the mean of typically developing children, and scores on speech production and everyday functioning were more than 1 SD below. Regression models accounted for 70-23% of variance in scores across different tests. Earlier CI switch-on and higher non-verbal ability were associated with better outcomes in most domains. Earlier HA fitting and use of oral communication were associated with better outcomes on directly administered language assessments. Severity of hearing loss and maternal education influenced outcomes of children with HAs. The presence of additional disabilities affected outcomes of children with CIs.

CONCLUSIONS

The findings provide strong evidence for the benefits of early HA fitting and early CI for improving children's outcomes.