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Characteristics of Hearing Aid Fittings in Infants and Young Children

McCreery, Ryan W.1; Bentler, Ruth A.2; Roush, Patricia A.3

doi: 10.1097/AUD.0b013e31828f1033
Research Articles

Objectives: Hearing aids (HAs) provide the basis for improving audibility and minimizing developmental delays in children with mild to severe hearing loss. Multiple guidelines exist to recommend methods for optimizing amplification in children, but few previous studies have reported HA fitting outcomes for a large group of children. The present study sought to evaluate the proximity of the fitting to prescriptive targets and aided audibility of speech, as well as survey data from pediatric audiologists who provided HAs for the children in the present study. Deviations from prescriptive target were predicted to have a negative impact on aided audibility. In addition, children who were fitted using verification with probe microphone measurements were expected to have smaller deviations from prescriptive targets and greater audibility than cohorts fitted without these measures.

Design: HA fitting data from 195 children with mild to severe hearing losses were analyzed as part of a multicenter study evaluating outcomes in children with hearing loss. Proximity of fitting to prescriptive targets was quantified by calculating the average root-mean-square (RMS) error of the fitting compared with Desired Sensation Level prescriptive targets for 500, 1000, 2000, and 4000 Hz. Aided audibility was quantified using the Speech Intelligibility Index. Survey data from the pediatric audiologists who fit amplification for children in the present study were collected to evaluate trends in fitting practices and relate those patterns to proximity of the fitting to prescriptive targets and aided audibility.

Results: More than half (55%) of the children in the study had at least 1 ear that deviated from prescriptive targets by more than 5 dB RMS on average. Deviation from prescriptive target was not predicted by pure-tone average, assessment method, or reliability of assessment. Study location was a significant predictor of proximity to prescriptive target with locations that recruited participants who were fit at multiple clinical locations (University of Iowa and Boys Town National Research Hospital) having larger deviations from target than the location where the participants were recruited primarily from a single, large pediatric audiology clinic (University of North Carolina). Fittings based on average real-ear to coupler differences resulted in larger deviations from prescriptive targets than fittings based on individually measured real-ear to coupler differences. Approximately 26% of the children in the study has aided audibility less than 0.65 on the Speech Intelligibility Index (SII). Aided audibility was significantly predicted by the proximity to prescriptive targets and pure-tone average, but not age in months.

Conclusions: Children in the study had a wide range of fitting outcomes in terms of proximity to prescriptive targets (RMS error) and aided speech audibility (SII). Even when recommended HA verification strategies were reported, fittings often exceeded the criteria for both proximity to the prescriptive target and aided audibility. The implications for optimizing amplification for children are also discussed.

Children with hearing loss receive hearing aids to minimize developmental delays. While guidelines exist on how amplification should be optimized for children, few studies have examined the characteristics of hearing aid fittings in children, including how the proximity of the fitting to prescriptive targets affects aided audibility. The present study evaluated these outcomes for 195 children with hearing loss, as well as survey data from pediatric audiologists who fit children in the study. Children with larger deviations from prescriptive target had poorer audibility, even when controlling for degree of hearing loss. Implications for clinical practice are discussed.

1Department of Audiology, Boys Town National Research Hospital, Omaha, Nebraska, USA; 2Department of Speech Pathology & Audiology, University of Iowa, Iowa City, Iowa, USA; and 3Department of Otolaryngology/Head and Neck Surgery, University of North Carolina, Chapel Hill, North Carolina, USA.

ACKNOWLEDGMENTS: The authors thank Elizabeth Walker, Research Associate; and Meredith Spratford, Research Audiologist. The authors also thank Shana Jacobs for her efforts in data collection and the audiologists who completed the survey for the present study. The audiology service provider survey was developed by Melody Harrison, Thomas Page, Meredith Spratford, Mary Pat Moeller, and Wendy Fick.

This work was supported by a National Institutes of Health/National Institute on Deafness and Other Communication Disorders RO1 DC009560 (Bruce Tomblin/Mary Pat Moeller Principle Investigators).

The authors declare no conflicts of interest.

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Address for correspondence: Ryan McCreery, Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE 68131, USA. E-mail: ryan.mccreery@boystown.org

© 2013 by Lippincott Williams & Wilkins