Longitudinal study of hearing aid effectiveness. I: Objective measures

Area of Science:

• Audiology
• Hearing Science
• Speech Perception

Background:

• Longitudinal studies are crucial for understanding long-term hearing aid efficacy.
• Objective measures and standardized tests assess hearing aid performance and user adaptation.
• Prescriptive fitting formulas, like NAL-R, guide initial hearing aid settings.

Purpose of the Study:

• To evaluate the longitudinal effects of hearing aid use on speech perception over 12 months.
• To assess user adherence to prescribed hearing aid settings (use gain).
• To investigate potential training effects and identify factors influencing speech perception changes.

Main Methods:

• Sixty-five hearing aid users were followed for 12 months post-fitting.
• Objective tests included insertion gain, Speech Perception in Noise (SPIN), and Nonsense Syllable Test (NST).
• Hearing aids were initially fitted using the NAL-R formula; use gain was measured at 6 and 12 months.

Main Results:

• Subjects generally adhered to prescribed hearing aid use gain, with exceptions in steeply sloping hearing loss configurations.
• No significant training effect on speech perception (NST, SPIN) was observed across the group or by subgroups.
• Adaptive filter circuits demonstrated less performance deterioration in noise compared to quiet settings on the NST.

Conclusions:

• Hearing aid use over 12 months did not yield significant improvements in speech perception scores.
• Adherence to prescribed gain is generally good, but individual factors like hearing loss configuration may influence usage.
• Adaptive filter circuits may offer a slight advantage in noisy environments by mitigating performance decline.