Preliminary evaluation of a method for fitting hearing aids with extended bandwidth

This paper describes a preliminary laboratory-based evaluation of a method for fitting hearing aids with an extended high-frequency response, called CAMEQ2-HF. Linear filtering was used to implement the CAMEQ2-HF-prescribed gains for speech with an input level of 65 dB SPL. The results obtained using four normal-hearing (NH) and fifteen hearing-impaired (HI) listeners showed: (1) The gains were sufficient to make components above 5 kHz audible when those components were presented alone, and when they were presented together with the lower-frequency components; (2) NH listeners preferred a wider bandwidth (10 or 7.5 kHz versus 5 kHz) for both pleasantness and speech clarity, while HI listeners usually preferred a narrower bandwidth for pleasantness but a wider bandwidth for clarity; (3) HI listeners performed better on the 'S-test' (detection of word-final /s/ or /z/) with a wider than with a narrower bandwidth (7.5 versus 5 kHz); (4) Identification of vowel-consonant-vowel nonsense syllables improved with increasing bandwidth from 5 to 7.5 kHz for the NH but not for the HI listeners.