Evaluation of electroacoustic test signals I: comparison with amplified speech.

OBJECTIVE

To evaluate the ability of clinical test signals to match the aided levels of real speech, across a range of hearing aid circuit types and strengths.

DESIGN

Hearing aids (N = 41) were set to DSL targets for moderate, severe, and profound hearing losses. These hearing aids were tested with three test signals (Fonix Pure Tones, Fonix Composite Noise, and Audioscan Swept), as well as with running speech. The difference between the aided test signal and the aided speech was calculated.

RESULTS

Accuracy of matches between aided test signals and aided speech levels depended on circuit type, signal type, and test level.

CONCLUSIONS

Clinical test signals can more accurately match the aided levels of speech for all types of hearing aids if they are 1) speech-weighted and 2) temporally modulated. Matches were more accurate at low to moderate test levels (i.e., 50 to 70 dB SPL), and less accurate at high test levels (i.e., 85 dB SPL).