Those experiencing hearing loss face severe challenges in perceiving speech in noisy situations such as a busy restaurant or cafe. There are many factors contributing to this deficit including decreased audibility, reduced frequency resolution, and decline in temporal synchrony across the auditory system. Some hearing assistive devices implement beamforming in which multiple microphones are used in combination to attenuate surrounding noise while the target speaker is left unattenuated. In increasingly challenging auditory environments, more complex beamforming algorithms are required, which increases the processing time needed to provide a useful signal-to-noise ratio of the target speech. This study investigated whether the benefits from signal enhancement from beamforming are outweighed by the negative impacts on perception from an increase in latency between the direct acoustic signal and the digitally enhanced signal. The hypothesis for this study is that an increase in latency between the two identical speech signals would decrease intelligibility of the speech signal. Using 3 gain / latency pairs from a beamforming simulation previously completed in lab, perceptual thresholds of SNR from a simulated use case were obtained from normal hearing participants. No significant differences were detected between the 3 conditions. When presented with 2 copies of the same speech signal presented at varying gain / latency pairs in a noisy environment, any negative intelligibility effects from latency are masked by the noise. These results allow for more lenient restrictions for limiting processing delays in hearing assistive devices.

Navigating conversations in complex auditory environments requires dynamic control of attention—switching and maintaining attention across multiple auditory objects. Several brain regions, some traditionally considered auditory and others non-auditory, have been highlighted as part of the cortical networks that contribute to the ability to switch and maintain attention between multiple talkers. M/EEG data were collected during a dual-stream auditory attention task in which the listener was asked to attend to one of two speech streams that differed in location or pitch. In each trial, the listener was cued to either maintain their attention on one talker, or switch their attention to the second talker during a silent interval. In this study, we apply a state-space model to the brain imaging data to elucidate the differences in the dynamic cortical networks responsible for maintaining and switching attention across different auditory cues.