Recording and classification of the acoustic environment of hearing aid users.

This article investigates the different acoustic signals that hearing aid users are exposed to in their everyday environment. Binaural microphone signals from recording positions close to the microphone locations of behind-the-ear hearing aids were recorded by 20 hearing aid users during daily life. The recorded signals were acoustically analyzed with regard to narrowband short-term level distributions.

Performance of a fully adaptive directional microphone to signals presented from various azimuths.

The signal-to-noise ratio advantage of a directional microphone is achieved by reducing the sensitivity of the microphone to sounds from the sides and back. A fully adaptive directional microphone (one that automatically switches between an omnidirectional mode and various directional polar patterns) may allow the achievement of signal-to-noise (SNR) improvement with minimal loss on audibility to sounds that originate from the sides and back. To demonstrate such possibilities, this study compared the soundfield aided thresholds, speech in quiet at different input levels, and speech in noise performance of 17 hearing-impaired participants under three microphone modes (omnidirectional, fixed hypercardioid, and fully [or automatic] adaptive) as the stimuli were presented from 0 degrees to 180 degrees in 45 degrees intervals.

Reconsidering the concept of the aided threshold for nonlinear hearing AIDS.

The aided threshold (and functional gain) has been discussed in the context of linear hearing aids since the early 1960s. The use of nonlinear hearing aids, however, could change the meaningfulness of this verification tool because of their unique characteristics. The interpretation of the aided threshold (and functional gain) as it pertains to linear and nonlinear hearing aids is reviewed.

Prediction of Intelligibility of Non-linearly Processed Speech.

Speech in various noise backgrounds was processed through four different non-linear devices and the intelligibility of the processed signals was predicted from the Speech Transmission Index (STI). A novel calculation method was applied in order to avoid artifacts. Running speech was used as input signal and STI was calculated from the envelopes of the squared, noise-free speech signal and of the processed, squared, noisy signal in 23 critical bands.