Current Research Projects
Research in our lab is focused on the neurobiological processes underlying hearing with a cochlear implant. We aim to use advances in knowledge to help improve the lives of people with cochlear implants. Primarily, we focus on the cognitive and sensory processing facors while listening in everyday environments.
Below are some of our ongoing research projects. For all of these we make use of behavioral measures and human brain imaging using electroencephalography (EEG).
Listening in quiet environments often occurs effortlessly. However, as soon as the environment gets more complex, for example trying to follow conversation in a noisy restaurant, or a pub, listening becomes more demanding. This requires more attention and taxes the cognitive system in order filter out the background noise. People with hearing aids or cochlear implants expend more mental energy than those with normal hearing. One reason is that speech sounds reaching the brain are more degraded because of the way the cochlear implant or hearing aid transforms the sound. In this scenario, the brain needs to interpret degraded speech signal and filter out the background noise. These processes require mental effort, and because of this cochlear implant and hearing aid users often report feeling "mentally exhausted" after a just a normal day at work. This line of research focuses on the brain mechanisms associated with listening effort. By understanding how the brain deals with this mental effort provides insights into how optimal device programming or rehabilitation strategies can be achieved.
The Cocktail Party Effect
The cocktail party effect
is the brain's ability to focus on one part of the auditory environment while "filtering out" the distracting sounds -- for example, following a conversation in a noisy environment. All of us experience problems following a speaker in noisy environments, however, people with cochlear implants have much more difficulty compared to normal hearing individuals. This area of research examines how the brain is able (or not able) to track attended speech and suppress distracting speech. By understanding the neural mechanisms of the cocktail party effect we can develop technologies to help cochlear implant users.
Relationships Between Hearing with a Cochlear Implant and Mild Cognitive Impairment
A growing body of literature
has shown that relationships exist between hearing loss and dementia. Can getting a cochlear implant help slow down the progression from mild cognitive impairement to dementia? This research question is currently being investigated in the lab.
Music therapy is a proven method to aid in rehabilation in various populations such as stroke and Parkinson's Disease. This research project is a joint venture with the University of Toronto Music Department and Sunnybrook. Cochlear implant users will participate in a music therapy intervention study at the university with regular visits to the Sunnybrook lab to look for brain changes associated with the therapy program.
Brain Computer Interfaces
One exciting project we are starting is the use of a Brain Computer Interface (BCI)to help people with cochlear implants. A BCI reads brain signals from the scalp sensors placed on the head and as uses this information to interact with a computer. There is a rich history of BCIs in the field of using thoughts to type on a computer.
See below an example of how a BCI is used for typing.
We are at a very early stage of developing this. Stay tuned!
Speech Perception Tests
We have developed a speech in noise test that involves minimal understanding of the English language - the Digits in Noise test. We are currently examining this test in English, Cantonese, Urdu and Italian speaking cochlear implant users.