Limitations and Uses of the Aided Audiogram

David B. Hawkins

doi:10.1055/s-2004-823047

Seminars in Hearing, Table of Contents

Semin Hear 2004; 25(1): 51-62
DOI: 10.1055/s-2004-823047

Limitations and Uses of the Aided Audiogram

David B. Hawkins¹

¹Mayo Clinic Jacksonville, Jacksonville, Florida

Tribute to Tom Tillman I was fortunate enough to be at Northwestern University during the “Carhart/Tillman/Olsen/Matkin/Noffsinger/Harford/Dallos” era. What a time to be entering the audiology field! This group of men was an inspiration because of their dedication to the field and their competence in their specialty areas. I took several courses from Tom Tillman and he served on my dissertation committee. I gained from him a respect for the precise nature of auditory research. If you study a topic, it has to be done with care and with certainty that everything is working exactly as you expected. I remember thinking, “If Tom Tillman did a piece of research it could be believed because he did it right.” Precise, careful, and accurate-qualities we all should remember as we undertake research in the field of audiology.

Abstract

Performance characteristics of hearing aids can be assessed through a variety of methods, including word recognition, sound quality and intelligibility judgments, probe-microphone measurements, aided sound-field thresholds, and functional gain. This article focuses on the use of aided sound-field thresholds and outlines many of the limitations of these measurements such as poor reliability, susceptibility to circuit and amplified room noise, time consuming nature of the measurements, the lack of any information about maximum output levels in the ear, and the restriction of only reflecting amplification for low-level inputs. A procedure that maps amplified speech signals into the residual dynamic range and provides information on maximum output levels is recommended as a more reliable and clinically useful alternative. Situations where aided sound-field measurements would seem to be justified include use with bone-conduction devices, cochlear implants, and middle ear implants. Even in these situations, however, the limitations of the measurements must be recognized.

KEYWORDS

Functional gain - aided sound-field thresholds - nonlinear circuitry - sound-field calibration - cochlear implants - middle-ear implants - probe-microphone measurements - DSL procedure

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References

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David B HawkinsPh.D.

Audiology Section, Mayo Clinic Jacksonville

4500 San Pablo Road

Jacksonville, FL 32224

Email: Hawkins.David@mayo.edu