Fit-to-Targets and Aided Speech Intelligibility Index Values for Hearing Aids Fitted to the DSL v5-Adult Prescription

Abstract

Background Matching hearing aid output levels to prescribed targets is a component of preferred practice, yet recent normative data on appropriateness of fittings are lacking. Verification measures that assess closeness of fit-to-target include raw deviations from target, root-mean-squared-error (RMSE) deviations from target, and aided Speech Intelligibility Index (SII) values. Establishing normative ranges for these measures may help hearing professionals determine whether a patient's fit-to-targets and/or aided speech audibility is typical for his or her degree of hearing loss. Purpose This article aims to characterize the range of fit-to-target and the range of aided SII associated with hearing aid fittings using the Desired Sensation Level version 5.0 (DSL v5-adult) prescription with adults, considering also hearing aid style, venting, and audiometric characteristics. Research design A descriptive and correlational study of data collected from a retrospective chart review. Results Hearing aid fittings to 281 ears were compiled. The four-frequency average deviation from target (RMSE) was within ± 5 dB of target in 77% of fittings for mid-level speech. Deviation from targets increased with hearing loss, particularly when the loss is greater than 85 dB hearing level or if the loss was steeply sloping. Venting increased the deviation from targets in the low frequencies. Aided SII values strongly correlated with the participants' hearing thresholds. Clinical ranges for RMSE and aided SII were developed for characterization of fitting outcomes. Conclusion Fitting to DSL v5-adult targets was observed within ± 5 dB absolute deviation, or within 5 dB RMSE, on average for typical adult hearing aid fittings. Confidence intervals for deviation from target and aided SII are proposed.

Detection, Speech Recognition, Loudness, and Preference Outcomes With a Direct Drive Hearing Aid: Effects of Bandwidth

“…It would appear that the impact of high-frequency energy was reduced when the low-frequency band was filtered out of the signal. Differences among other conditions, although statistically significant, were within the observed range of clinically typical deviations from target (Dao et al., 2021) and were within one audiometric step size. Compared with these reference points, this difference (2.2–3.4 dB in input level) is unlikely to be considered clinically significant and indicates that while the extended bandwidth signal was perceived, it may not have resulted in a large or problematic increase in loudness and might not affect fitting procedures based on loudness which, in this study, used the CAM2 prescription method.…”

Correspondência entre alvo e saída da prótese auditiva segundo as regras prescritivas NAL-NL1 e NAL-NL2

“…Our study compared the targets prescribed by the NAL-NL1 and NAL-NL2 with the hearing aid responses (REAR) obtained for weak (55 dB) and moderate (65 dB) wear time to identify the ideal range of adaptation for the experienced user. Several studies (9,10,12,20) mention different criteria for the adaptation of hearing aids, regardless of the prescription rule adopted, with…”

“…Thus, the ideal adjustment should be conducted and assessed considering not only the hearing thresholds but also individual factors, such as comfort and tolerance to the amplified sound. In addition, the data obtained from the electroacoustic verification of the individuals allowed building confidence intervals for the adaptation ranges to provide the speech therapist with a consistent starting point to adjust the hearing aids (20) .…”

Correspondência entre alvo e saída da prótese auditiva segundo as regras prescritivas NAL-NL1 e NAL-NL2

“…No presente estudo, realizou-se a comparação entre os alvos prescritos pela NAL-NL1 e NAL-NL2 e respostas com a prótese auditiva (REAR) obtidas para os sinais de fala de fraca (55 dB) e média (65 dB) intensidade, a fim de identificar a faixa de adaptação considerada ideal para o usuário experiente. Diversas pesquisas (9,10,12,20) citam critérios diferentes para adaptação das próteses auditivas, independentemente da regra prescritiva a ser utilizada, sendo que a faixa de ±10 dB é a mais recomendada. Notou-se que os indivíduos que integraram este estudo utilizavam suas próteses auditivas com ganho acústico entre ±3 e ±7 dB, de acordo com a frequência para as entradas sonoras de fraca e média intensidade.…”

“…Sendo assim, pode-se enfatizar, que o melhor ajuste deve ser realizado e avaliado considerando não apenas os limiares auditivos, mas também fatores individuais, como conforto e tolerância ao som amplificado. Além disso, a partir *valores não foram estabelecidos devido ao n reduzido para as frequências de 3 e 4 kHz do grupo de grau profundo Legenda: NAL-NL = National Acoustic Laboratories Non-Linear; n = número de orelhas ; dB = decibel; NPS = nível de pressão sonora; Hz = hertz; Mod = moderado dos dados obtidos na verificação eletroacústica dos indivíduos, puderam ser construídos intervalos de confiança das faixas de adaptação, a fim de fornecer ao fonoaudiólogo, um ponto de partida consistente para o ajuste das próteses auditivas (20) .…”