Gain analysis of self-fitting over-the-counter hearing aids : a comparative and longitudinal analysis
Loading...
Date
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
OBJECTIVES : To investigate the gain provided by self-fitting over-the-counter (SF-OTC) hearing aids compared to clinical NAL-NL2 targets, the differences between various FDA-approved SF-OTC devices, and potential changes in gain over time.
METHODS : Two experiments were conducted: (1) a cross-sectional comparison of six SF-OTC hearing aids (n = 43) and (2) a longitudinal evaluation of gain within five days of self-fitting and four additional time points (n = 15). Real-ear measurements (REMs) were used to measure gain.
RESULTS : SF-OTC hearing aid gain corresponded with 10 dB SPL but not 5 dB SPL criteria from NAL-NL2 targets. Differences between NAL-NL2 targets and gain did not differ significantly between devices. There were no significant changes in gain over time for any input level.
CONCLUSIONS : SF-OTC hearing aids generally provide user-selected gain levels lower than clinical targets, particularly at higher frequencies. The gain remains stable over time, indicating limited user adjustment after initial fitting. OTC hearing aid manufacturers should consider implementing fitting algorithms that allow for gradual user acclimatization.
Description
DATA AVAILABIITY STATEMENT : The datasets generated and/or analyzed for the current study are available from the corresponding author upon reasonable request.
SUPPLEMENTARY FIGURES : FIGURE S1: Experiment 1: (A) Distribution of conventional pure tone audiometric frequencies for the left ear, (B) Distribution of conventional pure tone audiometric frequencies for the right ear, n = 43. FIGURE S2: Experiment 2: (A) Distribution of conventional pure tone audiometric frequencies for the left ear, (B) Distribution of conventional pure tone audiometric frequencies for the right ear, n = 15. FIGURE S3: Comparison of average prescribed NAL-NL2 targets and average real ear levels measured at 55 dB (soft speech) for ears combined across OTC hearing aids. Shading indicates the tolerance limits (±5 dB) from the mean for NAL-NL2 prescriptive targets. FIGURE S4: Comparison of average prescribed NAL-NL2 targets and average real ear levels measured at 75 dB (loud speech) for ears combined across OTC hearing aids. Shading indicates the tolerance limits (±5 dB) from the mean for NAL-NL2 prescriptive targets. SUPPLEMENTARY TABLES : TABLE S1: Experiment 1: Frequency and percentage of measurements within 5 dB from NAL-NL2 targets across ears for average speech (65 dB SPL). TABLE S2: Experiment 1: Frequency and percentage of measurements within 10 dB from NAL-NL2 targets across ears for average speech (65 dB SPL). TABLE S3: Experiment 1: Average Root Mean Square Error for 500-6000 Hz across six self-fitting over-the-counter heating aids. Table S4: Experiment 2: Average Root Mean Square Error for 500-6000 Hz after initial fit and at follow-up intervals.
SUPPLEMENTARY FIGURES : FIGURE S1: Experiment 1: (A) Distribution of conventional pure tone audiometric frequencies for the left ear, (B) Distribution of conventional pure tone audiometric frequencies for the right ear, n = 43. FIGURE S2: Experiment 2: (A) Distribution of conventional pure tone audiometric frequencies for the left ear, (B) Distribution of conventional pure tone audiometric frequencies for the right ear, n = 15. FIGURE S3: Comparison of average prescribed NAL-NL2 targets and average real ear levels measured at 55 dB (soft speech) for ears combined across OTC hearing aids. Shading indicates the tolerance limits (±5 dB) from the mean for NAL-NL2 prescriptive targets. FIGURE S4: Comparison of average prescribed NAL-NL2 targets and average real ear levels measured at 75 dB (loud speech) for ears combined across OTC hearing aids. Shading indicates the tolerance limits (±5 dB) from the mean for NAL-NL2 prescriptive targets. SUPPLEMENTARY TABLES : TABLE S1: Experiment 1: Frequency and percentage of measurements within 5 dB from NAL-NL2 targets across ears for average speech (65 dB SPL). TABLE S2: Experiment 1: Frequency and percentage of measurements within 10 dB from NAL-NL2 targets across ears for average speech (65 dB SPL). TABLE S3: Experiment 1: Average Root Mean Square Error for 500-6000 Hz across six self-fitting over-the-counter heating aids. Table S4: Experiment 2: Average Root Mean Square Error for 500-6000 Hz after initial fit and at follow-up intervals.
Keywords
Self-fitting over-the-counter (SF-OTC), Real-ear measurements (REMs), Over the counter (OTC), Hearing aids, Gain
Sustainable Development Goals
SDG-03: Good health and well-being
Citation
Knoetze, M.; Manchaiah, V.; Cormier, K.; Schimmel, C.; Sharma, A.; Swanepoel, D.W. Gain Analysis of Self-Fitting Over-the-Counter Hearing Aids: A Comparative and Longitudinal Analysis. Audiology Research 2025, 15, 17. https://doi.org/10.3390/ audiolres15010017.