A H Shovels | PubMed Health

PubMed1995

Target-matched insertion gain derived from three different hearing aid selection procedures.

Three hearing aid selection procedures were compared to determine if any one was superior in producing prescribed real-ear insertion gain. For each of three subject groups, 12 in-the-ear style hearing aids with Class D circuitry and similar dispenser controls were ordered from one of three manufacturers. Subject groups were classified based on the type of information included on the hearing aid order form: (1) the subject's audiogram, (2) a three-part matrix specifying the desired maximum output, full-on gain, and frequency response slope of the hearing aid, or (3) the desired 2-cc coupler full-in grain of the hearing aid, based on real-ear coupler difference (RECD) measurements. Following electroacoustic adjustments aimed at approximating a commonly used target insertion gain formula, results revealed no significant differences among any of the three selection procedures with respect to obtaining acceptable insertion gain values.

Adult↗

PubMed1994

Aided listener preferences in laboratory versus real-world environments.

A wearable, fully digital, personal processing unit developed for the study of hearing aid fitting and digital signal-processing techniques was utilized in a preliminary study of hearing aid fitting validation. In a modified single-subject, multiple-baseline control design, 12 hearing-impaired listeners indicated their preferences for monaurally aided frequency response alternatives during an initial laboratory session, a real-world session, and a final laboratory session. Listeners' preferences, based on listening to connected speech, were stored in each environment by the personal processing unit. Within blocks of 3 each, subjects were time-lagged with respect to the number of trials to criterion. Subjects participated in 1 of 4 listening conditions, classified according to laboratory stimulus materials; speech recorded in an audiometric sound room in quiet or noise, and speech recorded in a reverberant room in quiet or noise. When compared with preferences obtained in the initial laboratory session, preferences obtained during the final laboratory session agreed better with those obtained in the real world. Overall, however, preferences under laboratory conditions were only fair predictors of preferences under everyday conditions. Results reveal the potential of harnessing the programming and storage capabilities of digital signal-processing technology in implementing new hearing aid fitting strategies.

Acoustic Stimulation↗