Design and assessment of an assistive wearable platform for acoustic spatial awareness

Partial hearing loss is a common condition: 360 Million people in the world suffer from disabling hearing loss. Recent technological advancements brought on the market hearing aids that improve speech understanding during conversations with a single human talker, or while watching television or during leisure activities. Nonetheless, very common acoustic scenarios such as noisy or crowded environments, or the presence of multiple surrounding talkers around the listener, are still problematic. This Ph.D. thesis exposes the concept of a novel device which is complementary to hearing aids and has the aim of increasing the speech comprehension in noise for people with hearing impairment. It consists of a couple of microphone arrays embedded in the temples of a pair of glasses. It can be connected to hearing aids or used by earphones and provides an effective spatial segregation of sounds by means of an implementation of robust beamforming filter synthesis. The experimental part of the thesis illustrates the three studies performed on participants with healthy hearing and hearing impairment to investigate the contribution of glasses spatial filtering to speech comprehension in noise and to compare it with previous art. Symmetric and asymmetric sound filtering configurations were tested and the results showed that the use of binaural spatial filtering offered by the device can further improve the speech comprehension of hearing impaired listeners compared to in-the-ear hearing aids. Moreover, it can be useful also for people with healthy hearing, to handle conversations with two speakers in noisy contexts.