Welcome Dr. Ewen MacDonald to SYDE

Tuesday, September 1, 2020

We welcome Dr. Ewen MacDonald, who comes to Systems Design Engineering as Associate Professor. Ewen MacDonald

Ewen received his Ph.D. in Biomedical Engineering in 2007 from the University of Toronto. His thesis work investigated the consequences of the loss of temporal synchrony on speech intelligibility in noise. The loss of synchrony in the auditory system reduces temporal information that is available to a listener's brain and can occur as a result of aging and/or synaptopathy (often referred to as "hidden" hearing loss).

Following his Ph.D., Ewen conducted postdoctoral research at Queen's University where he investigated the role of auditory feedback in the control of speech production. When we talk, we subconciously monitor the acoustics of the speech we produce to maintain communication. For example, at a noisy party, people automatically raise the level of their voice. However, we also monitor other acoustic properties of our speech. Using a time-varying filter, it is possible change the vowels in the words that people say in real-time.  In one line of experiments, Ewen investigated how we monitor vowel production. For example, when talkers said the word "head" into a microphone, they simultaneously heard themselves saying a different word, like "had", over headphones. When they received this altered feedback, most talkers altered their vowel production, saying a word that sounded more like "hid" rather than "head".

In 2011, Ewen moved to Copenhagen to take a faculty position at the Technical University of Denmark. There he continued his research into the perceptual consequences of hearing loss and how they can be addressed by hearing assistive devices. A recent focus of his research has been on the timing of turn taking in interactive conversation and how this can be used to evaluate hearing-aid signal processing.