Much of the hospital's success in identifying and treating children with hearing loss is the result of the rapid transfer of research findings from laboratories to clinic and bedside.

Areas of Research - Clinical and Behavioral Studies of Human Communication - Hearing Aid Research Laboratory

Overview

The overall goal of work in this lab is the development and validation of techniques for selecting and fitting advanced signal processing hearing aids to infants and young children. Recent studies have shown that children with hearing loss who are identified through universal newborn hearing screening programs are not as delayed in speech and language development as children who are identified at later ages. It appears, however, that even with early identification and intervention (including amplification), these children are still delayed relative to children with normal hearing. We believe that these persistent delays are the result of reduced auditory access and limited auditory experiences. Specifically, reduced auditory experience in infancy may compromise the auditory perceptual foundations upon which later language stages are constructed. It is critical to determine the constellation of auditory factors that support early learning and the experiences that facilitate continued language development throughout childhood. Thus, a primary goal of the research in this laboratory is to determine the acoustic needs of young children as they develop and learn to perceive speech through experience.

Facilities

Two laboratories at Boys Town National Research Hospital are devoted to these research efforts. One lab is located within the clinical audiological facility at the hospital and the other is located on the 3 rd floor where additional research laboratories are housed. Both laboratories are equipped with sound-attenuating booths, PCs, audiometers, tympanometers, electroacoustic analysis systems for hearing aids, CD players, and a variety of analog devices. Software is available for designing and running experiments, acoustic analysis of speech and other complex signals, signal generation, data entry, statistical analysis, and word processing.

The laboratories are designed to be child friendly and many of the data collection procedures are developed as computer games. Locally-developed game-based software facilitates speech perception testing for children as young as 3 years of age. Sounds and images are presented and children respond using a touch screen monitor. Parents can observe testing through a window and hear their child through a speaker system. After testing, children can select a toy or book to take home. Adults often are included in studies in order to compare their performance with that of children and/or to assess the efficacy of emerging technologies.

Staff

Research in this laboratory is under the direction of Dr. Patricia G. Stelmachowicz and has been supported by NIDCD since 1984. Dr. Dawna Lewis is responsible for the day-to-day operation of the laboratory. Other collaborators include Dr. Mary Pat Moeller, and Ms. Brenda Hoover.

Summary of Research Program

For Clinicians and Scientists

The research program focuses on the optimization of amplification for infants and young children with hearing loss. Past studies have focused on the role of high frequency audibility in phoneme recognition, the relation between context and stimulus audibility, the influence of hearing aid signal processing on novel word learning, acclimatization and hearing-aid signal processing, and the role of auditory experience in a child’s early phonological, lexical and morphological development. Current and future studies will explore ways in which to enhance auditory access and auditory experiences in young children with hearing loss. Studies have been designed to address the following questions: (1) What is the influence of selected forms of advanced signal processing on speech perception, speech production, novel-word learning, and ease of listening? (2) Can the quality and/or quantity of auditory experiences can be enhanced for the purpose of accelerating auditory skill development and adaptation to new signal-processing algorithms? It is our hope that these studies will result in the development of alternative intervention strategies that will improve speech and language outcomes for children with hearing loss.

For Families

The work in this laboratory is concerned with finding better ways to select and fit hearing aids to infants and young children. Previous studies have shown that the procedures and technologies used with adults do not always provide the same benefit to young children. For example, studies have found that young children require higher speech levels, less background noise, wider signal bandwidths, and less reverberation in order to perceive speech as well as adults. A recent study in our lab has shown that the speech and language skills of children who are identified with hearing loss and fitted with hearing aids prior to 12 months are approximately one year ahead of children who are identified later. It appears, however, even with early identification, young children with hearing loss are still delayed compared to children with normal hearing. Our current experiments are designed to determine why these delays exist. One goal is to determine if specialized signal processing can improve auditory access to speech. A second goal is to determine if specific training can speed auditory skill development. If successful, these techniques will improve speech and language development for children with hearing loss.

Professional Resources

Optimizing Amplification for Infants & Young Children (NIDCD, R01 DC04300)
Real-Ear-to-Coupler Difference Procedure (RECD)
Situational Hearing Aid Response Profile (SHARP)
Publications