Electrophysiology Lab
People
Dr. Steve Aiken, the lab director, often conducts research in collaboration with professors in the School of Communication Sciences and Disorders, , and Psychology and Neuroscience, as well as with clinicians at the . Current national and international collaborators include (University of Western Ontario), (University of Pittsburgh), Dr. Murad Almomani and Dr. Thomas Bosley (King Saud University, Saudi Arabia).
Location
The Dalhousie Electrophysiology Lab is located in the聽School of Communication Sciences and Disorders on the 2nd floor of the Sir Charles Tupper Medical Building, 5850 College Street. Additional clinically focused lab space for audiometry and brainstem assessment is available in the affiliated , which is embedded in the Otolaryngology department at the Queen Elizabeth II Health Sciences Centre of the Nova Scotia Health Authority
Lab Resources
The lab is equipped with an RF-shielded and double-walled sound booth, state-of-the-art equipment for measuring auditory responses from the brainstem and cortex, as well as acoustic and hearing aid test equipment. For cortical measurements, the lab contains a 140-channel Biosemi Active Two system with headcaps for adults, children and infants and a Polhemus system for three-dimensional mapping of electrode positions. Brainstem measurement equipment includes a Biosemi ABR module, Grass LP 511 amplifiers, a National Instruments PXI system for precise stimulus timing and response acquisition, a 6-channel Smart EP system and a 2-channel Vivosonic Integrity system. Otoacoustic emissions can be acquired with the Smart EP system or with the ER-10B+ microphone and custom software. For hearing aid work, the lab has a Noah/Hi-Pro station and an Audioscan Verifit, as well as a KEMAR with GRAS microphones, an ER-7 real ear microphone and the National Instruments Sound and Vibration Measurement Suite. Other equipment includes a GSI 61 audiometer and an analysis workstation with BESA software.
Current Research
- Brainstem Responses to Speech Sounds
Speech sounds are richly represented in the synchronized activity of the auditory nerve and brainstem, which is reflected in tiny voltage fluctuations that can be easily measured at the scalp. The patterns are so precise that it is possible to hear the speech sounds by listening to the electrophysiological activity. These responses offer insight about the physiological basis of normal and abnormal auditory processing and may hold considerable clinical value. Research in the lab is focused on clarifying the components of this response and investigating the relationship between the response and auditory function and pathology. - Cortical Responses to Speech Sounds
Responses measured from the cortex provide insight about the representation of speech at the highest levels. Temporal patterns in the auditory cortex have been shown to follow timing patterns in speech related to phonemes and syllables, including important speech information such as formant movements. Research being conducted in the laboratory is concentrated on exploiting these characteristics to gain a better understanding of normal and abnormal speech processing. - Binaural Processing
Some of the most interesting aspects of hearing relate to how information is combined between the two ears. These processes are very important for hearing in noise and making sense out of complex auditory environments. Many binaural processes can be studied by recording electrophysiological responses from the brainstem and cortex. Current work in the laboratory is focused on the effects of asymmetric hearing loss on these responses and on auditory perception. - Hearing Aid Processing
Hearing aid processing has become more sophisticated in recent years but hearing aid fitting is based almost exclusively on compensating for shifts in hearing thresholds. Compensating for supra-threshold hearing deficits could be very helpful and could improve speech understanding for many people with hearing problems. This will require a better understanding of how different types of hearing aid processing mediate the impact of supra-threshold auditory deficits on speech perception.聽 Current research in the laboratory is investigating the relationship between brainstem timing, hearing aid processing characteristics and speech perception.
Prospective Master鈥檚 and PhD students and Research Assistants:
We are open to applications to study in Master鈥檚 or doctoral programs or for the position of research assistant.