Functional Gain
The difference in decibels between unaided and aided soundfield thresholds, used to estimate the real-world benefit of amplification.
Full Definition
Functional gain is calculated by subtracting aided soundfield thresholds from unaided soundfield thresholds at each test frequency, expressing the benefit of amplification in behavioral terms. While intuitively meaningful, functional gain has largely been supplemented by real-ear measurement as a verification tool, since it is subject to greater test–retest variability and floor effects near normal hearing levels. Editors should note that functional gain is a soundfield measure and should not be confused with coupler gain or insertion gain, which are electroacoustic measures. The term is always written as two words.
Usage
Usage note: Editors should flag use of 'functional gain' as a synonym for 'real-ear gain' or 'insertion gain,' as these are distinct measurement paradigms with different clinical implications.
In Context
- "Functional gain at 2000 Hz was 28 dB, suggesting adequate high-frequency amplification." — Pediatric hearing aid verification report
- "Functional gain measures were recorded to document aided benefit for the patient's school file." — Educational audiology report