Perceptual Implications of Level- and Frequency-Specific Deviations from Hearing Aid Prescription in Children

Abstract

Background The purpose of providing amplification for children with hearing loss is to make speech audible across a range of frequencies and intensities. Children with hearing aids (HAs) that closely approximate prescriptive targets have better audibility than peers with HA output below prescriptive targets. Poor aided audibility puts children with hearing loss at risk for delays in communication, social, and academic development. Purpose The goals of this study were to determine how well HAs match prescriptive targets across ranges of frequency and intensity of speech and to determine how level- and frequency-dependent deviations from prescriptive target affect speech recognition in quiet and in background noise. Study Sample One-hundred sixty-six children with permanent mild to severe hearing loss who were between 6 months and 8 years of age and who wore HAs participated in the study. Data Collection and Analysis Hearing aid verification and speech recognition data were collected as part of a longitudinal study of communication development in children with HAs. Hearing aid output at levels of soft and average speech and maximum power output were compared with each child’s prescriptive targets. The deviations from prescriptive target were quantified based on the root-mean-square (RMS) error and absolute deviation from target for octave frequencies. Children were classified into groups based on the number of level-dependent deviations from prescriptive target. Frequency-specific deviations from prescriptive target and sensation levels (SLs) were used to estimate the proximity of fittings across the frequency range. Lexical Neighborhood Test (LNT) word recognition in quiet and Computer-Assisted Speech Perception Assessment (CASPA) phoneme recognition in noise were compared across level-dependent error groups and as a function of SL at 4 kHz. Results Children who had deviations from prescriptive target at all three input levels had poorer LNT word recognition in quiet than children who had fittings that matched prescriptive target within 5 dB RMS at all three input levels. Children with lower 4 kHz SLs through their HAs had poorer LNT recognition in quiet and CASPA phoneme recognition in noise than children with higher aided SLs. Conclusions Children with HAs fitted to provide audibility for speech across a range of inputs and frequencies had better speech recognition outcomes than peers with HAs that were not optimally fitted to prescriptive targets.

Evaluation of Hearing Aid Manufacturers' Software-Derived Fittings to DSL v5.0 Pediatric Targets

“…The children in the group who had under-fitted hearing aids at all test levels had significantly poorer aided speech recognition scores than did children in the other groups, and this effect was most pronounced for children who were underfit in the high frequencies (McCreery et al). 19 As summarized earlier, we observed that although most manufacturers' fittings met this AE 5-dB criterion, some did not. This results in a pattern of under-fitting in the high frequencies that is similar to that observed by McCreery et al (2017), which was speculated to relate to a lack of routine verification.…”

“…We also computed the summary RMSE measure to quantify overall FTT, using methods recommended by McCreery et al 19,20 It is typically recommended that this value be <5-dB RMSE. We observed values of 4.5 dB for the five mildest audiograms at all test levels (►Table 3).…”

“…Proximity of fit to targets both overall and in the high frequencies has been shown to predict positive long-term outcomes for children who use hearing aids (McCreery et al). 18,19 It is recommended that clinicians verify hearing aid fittings to a validated evidence-based hearing aid prescription using real-ear measurement or coupler-based verification corrected with either a measured or age-appropriate real-ear-to-coupler difference (RECD) (AAA) 1 ; however, it is possible for the clinician to use the manufacturer's software to set the hearing aid's frequency gain response without verification. These software-derived fittings rely on the manufacturer's implementation of the prescriptive method within their software and lack the feedback of measurement of the actual output of the hearing aid for either calibrated speech or high-level signals for maximum output.…”

“…In the present study, we examined the accuracy of softwarederived hearing aid fittings to the DSL v5.0 pediatric targets by verifying the output of the hearing aid from a range of major hearing aid manufacturers. The objectives of this study were to (a) evaluate the software-derived fit to targets using frequencyspecific measures to determine which audiograms were fitted within AE 5 dB per frequency as recommended by Moodie et al (2017); (b) evaluate the fit to targets using the RMSE index to determine whether software-derived fittings fall within a commonly recommended 5 dB value (Baker and Jenstad; 8 Moodie et al; 22 McCreery et al;) 18,19 and (c) report the aided SII value against normative data to determine whether softwarederived fittings fall within the same range as verified hearing aids reported by Moodie et al (2017).…”

Comparison of auditory brainstem response and auditory steady state response audiometry by evaluating the hearing thresholds obtained in children with different severity of hearing loss

“…Although ABR is well established and time tested objective audiological test for early identification of hearing loss but it provides limited frequency specific information 3. Early auditory rehabilitation whether by modern hearing aids or by cochlear implants depends strongly on frequency specific hearing threshold information 4. To overcome this limitation of ABR, a relatively new audiological investigation is gaining popularity in clinical audiological practice which can provide detailed frequency specific thresholds information.…”