National Centre for Audiology

Speech Auditory Feedback & Evoked Responses Laboratory

Research Overview

Our research examines the human auditory system and the role that it plays in speech production. When we talk, the sound of our own voice is important in the accurate maintenance of speech. We study this by changing speech sounds in real-time (altered auditory feedback) and observing the influence on talking. We also study the auditory system by recording the sounds produced by the ear (otoacoustic emissions) or the electrical activity generated by the brain (auditory electrophysiology) in response to sound. We are particularly interested in the brain's response to speech sounds (speech evoked potentials). Read on for some examples or browse our publication list! Feel free to contact Dr. Purcell if you have any questions. People associated with the lab past and present can be visited here!

One of our interests is physiological measurements of auditory function such as otoacoustic emissions (OAEs) and steady-state auditory evoked potentials (the ASSR or SSAEP). We are interested in developing new ways of using the objective measurements that we have available, as well as relating these to performance in perceptual tasks. For example, we have developed methods of estimating auditory processing delays, as well as tools for evaluating the auditory brainstem's neural connections between ears (via the olivocochlear efferent system). We have studied how an individual's ability to detect amplitude modulation perceptually is related to their brain's ability to follow the modulated signal as measured electrophysiologically. Our recent work has explored the brain's envelope following response (the EFR) to individual vowel formants in speech. These vowel responses may have a practical application in validating newly fit hearing aids in very young listeners. We are also interested in how the brain follows the fine structure of speech, the frequency following response (the FFR).

Recruiting graduate students! 

Funded thesis based Masters and PhD degrees can be pursued in the SAFER Lab through the Hearing Science field in the Health & Rehabilitation Sciences Graduate Program or through the Graduate Program in Neuroscience. A funded, combined PhD and clinical Masters in Audiology (MClSc) is also an option. The research areas pursued in my laboratory will be of interest to students from psychology, neuroscience, communication sciences, physiology, medical biophysics, life sciences, health sciences, or other related areas

Connect with Us


David Purcell, PhD, is the Director of the Speech, Auditory Feedback, and Evoked Responses (SAFER) Laboratory and an Associate Professor of the School of Communication Sciences & Disorders, Faculty of Health Sciences. Dr. Purcell studies the processing of sound in the human auditory system and the links between processing of one’s own speech sounds and the maintenance of speech production.
519-661-2111 x80435