Perceptual effects of processing and transmission delay in hearing technology

University Of Illinois At Chicago, Chicago IL

Investigators

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Abstract

PROJECT SUMMARY/ABSTRACT Next-generation hearing assistive technology will be driven by digital processing and digital connectivity, but both can introduce disturbing delays. Advanced signal processing algorithms like noise reduction and dereverberation perform best when they are allowed longer processing delay, and digital wireless devices like remote microphones can greatly improve intelligibility but introduce significant transmission delays. Today, hearing aids use strict delay constraints of about ten milliseconds in all conditions. However, listeners might be able to tolerate greater delay in some conditions, especially in exchange for higher-quality signals. A better understanding of tolerable limits for processing delay and transmission delay would help engineers to develop innovative digital algorithms and system architectures for hearing technology. This project will measure delay tolerance under realistic conditions using a set of experiments in which two subjects hold a spontaneous conversation using hearing devices with variable delays. First, the researchers will validate this new protocol and compare it against conventional listening and speaker tasks. Next, the researchers will measure tolerable transmission delays for wireless remote microphones, which have been shown to dramatically improve intelligibility in noise but are limited by the high latency of digital wireless protocols like Bluetooth. Finally, they will study the effects of environmental noise and reverberation on delay tolerance. If users can tolerate greater delay in challenging noisy and reverberant environments, then algorithms could dynamically adjust their delay and enhancement performance based on acoustic conditions. Delay is arguably the greatest technical roadblock to developing innovative connected hearing systems that could dramatically improve quality of life for people with hearing loss. Before technology developers can hope to address the technical challenges, they must better understand the perceptual constraints and tradeoffs.