The results clearly indicate that binaural advantages can be obtained from using a hearing aid with a cochlear implant in opposite ears. It is recommended that bimodal stimulation be standard practice for rehabilitation of adults who wear unilateral cochlear implants. A hearing aid should be fitted to the nonimplanted ear using the NAL-NL1 prescription as a starting point, and the frequency response slope and gain could be fine-tuned to suit individual needs.

Two experiments were conducted to examine the relationship between audibility and speech recognition for individuals with sensorineural hearing losses ranging from mild to profound degrees. Speech scores measured using filtered sentences were compared to predictions based on the Speech Intelligibility Index (SII). The SII greatly overpredicted performance at high sensation levels, and for many listeners, it underpredicted performance at low sensation levels. To improve predictive accuracy, the SII needed to be modified. Scaling the index by a multiplicative proficiency factor was found to be inappropriate, and alternative modifications were explored. The data were best fitted using a method that combined the standard level distortion factor (which accounted for decrease in speech intelligibility at high presentation levels based on measurements of normal-hearing people) with individual frequency-dependent proficiency. This method was evaluated using broadband sentences and nonsense syllables tests. Results indicate that audibility cannot adequately explain speech recognition of many hearing-impaired listeners. Considerable variations from audibility-based predictions remained, especially for people with severe losses listening at high sensation levels. The data suggest that, contrary to the basis of the SII, information contained in each frequency band is not strictly additive. The data also suggest that for people with severe or profound losses at the high frequencies, amplification should only achieve a low or zero sensation level at this region, contrary to the implications of the unmodified SII.

NAL-NL2 is the second generation of prescription procedures from The National Acoustic Laboratories (NAL) for fitting wide dynamic range compression (WDRC) instruments. Like its predecessor NALNL1 (Dillon, 1999), NAL-NL2 aims at making speech intelligible and overall loudness comfortable. This aim is mainly driven by a belief that these factors are most important for hearing aid users, but is also driven by the fact that less information is available about how to adjust gain to optimise other parameters that affect prescription such as localisation, tonal quality, detection of environmental sounds, and naturalness. In both formulas, the objective is achieved by combining a speech intelligibility model and a loudness model in an adaptive computer- controlled optimisation process. Adjustments have further been made to the theoretical component of NAL-NL2 that are directed by empirical data collected during the past decade with NAL-NL1. In this paper, the data underlying NAL-NL2 and the derivation procedure are presented, and the main differences from NAL-NL1 are outlined

There are now many recipients of unilateral cochlear implants who have usable residual hearing in the non-implanted ear. To avoid auditory deprivation and to provide binaural hearing, a hearing aid or a second cochlear implant can be fitted to that ear. This article addresses the question of whether better binaural hearing can be achieved with binaural/bimodal fitting (combining a cochlear implant and a hearing aid in opposite ears) or bilateral implantation. In the first part of this article, the rationale for providing binaural hearing is examined. In the second part, the literature on the relative efficacy of binaural/bimodal fitting and bilateral implantation is reviewed. Most studies on comparing either mode of bilateral stimulation with unilateral implantation reported some binaural benefits in some test conditions on average but revealed that some individuals benefited, whereas others did not. There were no controlled comparisons between binaural/bimodal fitting and bilateral implantation and no evidence to support the efficacy of one mode over the other. In the third part of the article, a crossover trial of two adults who had binaural/bimodal fitting and who subsequently received a second implant is reported. The findings at 6 and 12 months after they received their second implant indicated that binaural function developed over time, and the extent of benefit depended on which abilities were assessed for the individual. In the fourth and final parts of the article, clinical issues relating to candidacy for binaural/ bimodal fitting and strategies for bimodal fitting are discussed with implications for future research.

Objectives 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. Based on 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. Based on 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 one standard deviation (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.

Hearing aids for children who also use cochlear implants can be selected using the NAL-RP prescription. Adjustment of hearing aid gain to match loudness in the implanted ear can facilitate integration of signals from both ears, leading to better speech perception. Given that there are binaural advantages from using cochlear implants with hearing aids in opposite ears, clinicians should advise parents and other professionals about these potential advantages, and facilitate bilateral amplification by adjusting hearing aids after stable cochlear implant MAPs are established.

The Parent's Evaluation of Aural/Oral Performance of Children (PEACH) was developed to evaluate the effectiveness of amplification for infants and children with hearing impairment by a systematic use of parents' observations. The PEACH was administered to 180 parents (one parent of each of 90 children with normal hearing that ranged in age from 0.25 to 46 months, and 90 children with hearing impairment that ranged in age from 4 months to 19 years). The internal consistency reliability was 0.88, and the test-retest correlation was 0.93. Normative data are presented to enable performance of children with hearing impairment to be related to their normally hearing peers and/or other children with similar degrees of hearing loss. Ninety and ninety-five percent critical differences are presented to facilitate evaluation of differences between scores obtained under different conditions for the same individual. The PEACH can be used with infants as young as one month old and with school-aged children who have hearing loss ranging from mild to profound degree.

Early intervention improves language outcomes, thereby lending support to streamlining clinical pathways to ensure early amplification and cochlear implantation after diagnosis.