Comparison of functional gain and insertion gain in hearing-aid users with tympanic membrane perforations
Journal
Journal of Taiwan Otolaryngology - Head and Neck Surgery
Journal Volume
34
Journal Issue
6
Pages
462-466
Date Issued
1999
Author(s)
Abstract
BACKGROUND: The purpose of this study is to investigate the relationship between functional gain and insertion gain in people with tympanic membrane perforation who use hearing aids. METHODS: Ten perforated ears served as the experimental group. The control group consisted of ten ears with comparable sensorineural hearing loss. Functional gain was obtained by subtracting the unaided threshold from the aided threshold in sound field audiometry. Insertion gain was measured using a Fonix 6500 probe-tube microphone system. RESULTS: In the control group, the average functional gains did not differ from the insertion gains across all frequencies. In the experimental group, the average insertion gains were significantly larger than functional gains in all frequencies. The differences between insertion gain and functional gain had a high positive correlation (r=0.86) with the average air-bone gap in the experimental group. CONCLUSIONS: Probe-tube microphone measurements of insertion gain substantially overestimate the functional gain of subjects with ear drum perforations. The difference is especially noticeable in patients with larger air-bone gaps. Therefore, the results of real ear measurements should be interpreted with caution.
Subjects
Functional gain; Hearing aid; Insertion gain; Tympanic membrane perforation
SDGs
Other Subjects
adult; article; audiometry; auditory threshold; clinical article; eardrum perforation; functional assessment; hearing aid; human; microphone; perception deafness
Type
journal article