Welcome to the MASTER homepage

The MASTER (multiple auditory steady-state evoked response) system was developed at the Rotman Research Institute at the Baycrest Centre. The Rotman Research Institute is fully affiliated with the University of Toronto.

The MASTER system and technique is currently being developed in Dr. Terry Picton's laboratory by Sasha John, Andrew Dimitrijevic, and David Purcell. Research systems are available. For questions e-mail sjohn@rotman-baycrest.on.ca.

Download a demo of the latest version of MASTER now!

Click here to learn about the flexible/research-oriented and CSA approved MASTER system available for researchers and clinicians who want to use the latest innovative MASTER stimuli and techniques. Multi-Master software contains the newest stimuli for ASSR testing including clicks and noise stimuli. Click here to download documentation on the Multi-MASTER software.

Click here to learn about the clinically oriented and FDA approved MASTER system available from Natus Medical Incorporated (formally Bio-logic Systems Corp.)


The Multiple Auditory STEady-state Response (MASTER) technique allows the simultaneous evaluation of 4 tonal frequencies in each ear. Our research into auditory steady-state responses or "ASSRs" (which may also referred to as by other terms, such as, the amplitude modulation following response "AMFR", envelope following response "EFR") entails developing robust techniques for performing frequency specific audiometry. This second stage of hearing evaluation permits frequency specific threshold estimation to be obtained for infants who did not pass a universal newborn hearing screening test. Because an infant can not "tell" an audiologist if a sound can not be heard, analyzing the brain activity of the infant (EEG) permits an objective manner of generating its audiogram. The MASTER technique should be faster than current tone-ABR techniques and is more thorough than oto-acoustic emissions testing (because it detects both central and peripheral deficits), and is therefore emerging as in important clinical procedure for performing pediatric hearing evaluations and assisting in their subsequent treatment with hearing aids. In addition to this central clinical role (realized by FDA approved systems such as those made by Bio-logic Systems corporation and GSI's Audera, as well as the Audix, and the Smart EP-ASSR made by Intelligent Hearing System) the MASTER technique is being used to investigate abilities of the auditory system such as speech processing capacities, ability to process both frequency and amplitude modulation, ability to follow rapid changes in a sound (modulation transfer function), and even gap detection. For more information please see our publications section.