Hearing Aid Phase II-B Study
[Order Report] [Executive Summary]
The Hearing Aid Phase II-B Study measured speech recognition and annoyance of 24 hearing aid wearers with five levels of the IRIS signal for each phone technology mixed with speech at 65 dB SPL. The research evaluated a number of measures (SPL, A-weighted SPL, C-weighted SPL, PSIL, and AI) to determine which best represented the impact of the interference on speech recognition, independent of the phone technology being used. Speech recognition was reduced only slightly for speech-to-interference levels of 20 to 30 dB SPL, but was substantially affected for lower ratios (losses up to 87%). PCS 1900 produced greater losses at 0 and -10 dB than did the other technologies. Annoyance ratings appeared to increase linearly with increases in the interference level from 35 dB SPL (rating 0.2) to 75 dB SPL (rating 4.0). The Articulation Index (AI) corresponded best with the obtained scores across the phone signals, and was a good indicator of the effectiveness of speech communication for hearing aid wearers using digital wireless phones.
|
|
Figure 1: Average Absolute Speech Intelligibility Score (%) by Phone Technology and Speech-to-Noise Ratio.
|
|
Figure 2: Average Absolute Speech Intelligibility Score (%) by Hearing Loss Configuration.
