  When listening to a sound source in everyday-life situations, typical
movement behavior can lead to a mismatch between the direction of the head and
the direction of interest. This could reduce the performance of directional
algorithms, as was shown in previous work for head movements of normal-hearing
listeners. However, the movement behavior of hearing-impaired listeners and
hearing aid users might be different, and if hearing aid users adapt their
self-motion because of the directional algorithm, its performance might
increase. In this work we therefore investigated the influence of hearing
impairment on self-motion, and the interaction of hearing aids with
self-motion. In order to do this, the self-motion of three hearing-impaired
(HI) participant groups, aided with an adaptive differential microphone (ADM),
aided without ADM, and unaided, was compared, also to previously measured
self-motion data from younger and older normal-hearing (NH) participants. The
self-motion was measured in virtual audiovisual environments (VEs) in the
laboratory. Furthermore, the signal-to-noise ratios (SNRs) and SNR improvement
of the ADM resulting from the head movements of the participants were estimated
with acoustic simulations. A strong effect of hearing impairment on self-motion
was found, which led to an overall increase in estimated SNR of 0.8 dB for the
HI participants compared to the NH participants, and differences in estimated
SNR improvement of the ADM. However, the self-motion of the HI participants
aided with ADM and the other HI participants was very similar, indicating that
they did not adapt their self-motion because of the ADM.
