Digital Versus Analog Signal Processing: Effect of Directional Microphone

Abstract

Differences in performance were evaluated between the Widex Senso C8 (omnidirectional) and C9 (directional) hearing aids and analog hearing aids currently worn by 40 subjects with hearing loss. Subjects were fit with the C8 and C9 using the manufacturer's recommended procedure. Differences in performance between the C8 and C9 and the subjects' own hearing aids were assessed using the Speech Perception in Noise (SPIN) test administered at +7, 0, and -7 dB signal-to-noise ratio (SNR) with the noise fixed at 65 and 75 dB SPL. Also, a questionnaire was completed assessing differences in preference between the C9 and the subjects' own hearing aids. The major finding was the presence of a significant advantage of the C9 relative to the C8 and the subjects' own hearing aids at each experimental condition. The magnitude of the advantage provided by the C9 increased as the SNR became more difficult. However, significant differences were not present between the C8 and the subjects' own hearing aids at any experimental condition. The questionnaire revealed a statistically significant preference for the C9 in comparison to the subjects' own hearing aids. Abbreviations: ANSI = American National Standards Institute, BTE = behind the ear, CIC = completely in the canal, DSP = digital signal processing, FBR = front-to-back ratio, HP = high predictability, ITE = in the ear, LP = low predictability, PI = performance intensity, SNR = signal-to-noise ratio, SPIN = Speech Perception in Noise