ATTENTUATION OF THE OUTPUT SIGNAL BY PROTECTIVE AND FIXING TOOLS FOR HEARING AIDS AND COCHLEAR IMPLANTS

The aim was to study amount of attenuation of input signal at the hearing aid (HA) or cochlear implant sound processor (SP) microphone by different protective tools or clothes. Materials and methods. The acoustic measurements were conducted in the soundproof cabin using artificial head with HA/SP and different protective tools, which can influence on microphone function. Probe microphone was integrated in the microphone input of SP and connected with HA verification system. Results. The biggest amount of signal attenuation was observed using water-resistant cases for SP. Changes affect the speech spectrum, therefore using such protective tools can lead to decrease of speech intelligibility. Maximum attenuation was 9.36±0.33 dB at 4000 Hz. Non-hermetic membrane protective cases gave maximum attenuation 7.67±0.18 dB (5000 Hz). Clothes which cover head lead to significant change of signal at microphone up to 9.24±0.16 dB mostly at high-frequencies, which less influences on speech intelligibility. The results confirm that clothes and protective tools for HA of SP show significant attenuation of sounds.