My research strives to shed light on how the human auditory system processes sound. This effort has resulted in clinical devices which are used to evaluate hearing in both infants and adults. By way of evaluating neurophysiological correlates of auditory processing key advances in the field of objective audiometry using auditory steady-state responses (ASSRs) have been made. My early work with Dr. Terry Picton helped form a solid foundation for what we have termed the multiple auditory steady-state response (MASTER) technique and demonstrated how the manipulation of several key parameters either improved or degraded the performance of this testing technique. The understanding obtained in these early studies, has recently enabled us to make several advances that have significantly increased the power, speed, accuracy, and comprehensiveness of the technique. Our laboratory has introduced new types of stimuli that evoke more robust responses and thereby permit a more rapid and accurate evaluation of the auditory system's capacity for detecting both frequency modulation and amplitude modulation. The responses evoked by these novel stimuli are positively correlated with an individual's speech processing abilities. The technique may serve to objectively quantify both the processing deficiencies that underlie hearing deficits, and also the efficacy of hearing aid devices in overcoming these deficits.
Profile Link: http://research.baycrest.org/sjohn
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