The influence of hearing aid nonlinear distortion on two auditory tasks.

A study is reported which examines the influence of hearing aid nonlinear distortion on multitone pitch perception. Normal-hearing subjects produced results indicating that hearing aid-generated harmonic and intermodulation components did significantly affect pitch judgments. Substantial differences in the amount of distortion between the two test aids was not, however, a critical factor. A follow-up study using closed-set intelligibility materials in noise further confirmed that relatively large measurable differences in nonlinear distortion between hearing aids do not seem to have the clinical significance which is often presumed.