SickKids

Cochlear Implant Program

        

Research activities

Research Update (May 2007)

Research in the Cochlear Implant Program at The Hospital for Sick Children seeks to promote auditory development for children who have hearing loss.  Specific research questions are posed in the many projects presently underway.  Some examples are:

1) Bilateral auditory processing in children using bilateral cochlear implants.  

Bilateral processing provides important hearing cues which are missed in children who use only one implant.  Can binaural processes be established in children using two implants?

2) The effects of deafness on the vestibular (balance) system

Deficits in balance have been shown in children who have profound deafness.  Are we making this problem better or worse with cochlear implants?

3)  Development of the auditory brain in children with unilateral hearing loss: an MEG study

Does unilateral hearing loss compromise normal response patterns from the auditory brain (cortex)?  

4) Effects of mutations in the GJB2 gene on the auditory pathways

What are the impacts of different types of GJB2 mutations on auditory pathway formation and development?

We are also interested in addressing important clinical issues related to children with hearing loss.  We continue to ask questions about what factors contribute or detract from children’s ability to use a cochlear implant effectively in order to help support optimal outcomes after implantation.  We have been specifically interested in the effects of age and duration of deafness; communication mode; and socio-economic factors.

In other work, we use electrophysiological tools to help find optimal stimulation levels for children who are too young or otherwise unable to tell us what they hear or feel with their cochlear implant.  We are presently developing protocols both in the operating room and in the clinic to best obtain and use these responses. 
 
Our laboratory has grown in size and numbers.  Our team is lead by Karen Gordon and Blake Papsin and joined by Robert Harrison and Adrian James.  Mr. Jerome Valero is the lab’s Senior Research Assistant and we support the work of several students, Sharon Cushing, Mr. Dan Wong, Ms. Claire Salloum, who are pursuing graduate research degrees in our lab. We also acknowledge dedicated work from students Ramya Sadashiva, Mr. Sho Tanaka, Ms. Lesley Hayward, Philip Lai, Ms. Talar Misakyan, and Ms. Tara Vongpaisal.  Many of our students enjoy returning to the lab; Evan Propst and Taryn Davids, for example, continue to participate in ongoing research studies. Audiologists, Vicky Papaioannou, Gina Sohn, Laurie MacDonald, and Ruth Chia are an integral part of our research team as are Auditory-Verbal Therapists, Clara Kluge and Nancy Greenwald-Hood, Social Worker, Hayley Fisher and Psychologist, Maria Kokai.  Outstanding administrative support is provided by Alice Forbes and Patricia Fuller.
 
We have several important research collaborations.  Sandra Trehub and her research team in the Department of Psychology at the University of Toronto are working with us to understand the functional impacts of bilateral and unilateral cochlear implantation; Tracy Stockley, a Geneticist in the Department of Paediatric Laboratory Medicine at SickKids, collaborates on our efforts to understand the role of genetics in hearing loss; Susan Blasér, a radiologist at SickKids, lends her specialized interest in the temporal bone to help assess the many different effects of deafness on the structure of the ear and auditory system; Mark Crawford, Department of Anaesthesia at SickKids, is helping us to understand how the auditory system responds immediately after cochlear implantation in the operating room; equipment designed and engineered by Robert Cowen and Richard van Hoesel, from the CRC-HEAR in Melbourne, Australia have helped us measure interaction along the auditory pathways stimulated by bilateral cochlear implants; and Maureen Dennis, has contributed to our understanding of the limitations in speech perception possible with current implant devices.
 
Finally, our studies are supported by research grants from the Canadian Institutes of Health Research, the Hearing Foundation of Canada, the SickKids Foundation, the Ontario Physician’s Services Inc., and by the families and children who donate their time and effort to our research efforts.

Lab History

The "Ribbon Cutting" ceremony marking the official opening of the Cochlear Implant Laboratory at The Hospital for Sick Children was held on July, 1998. However, it was well before this date that the lab was born. The initial plans for the lab were drawn up many months before the opening by Dr. Papsin. Karen Gordon then spent several months setting up the laboratory facilities and ensuring proper functioning of all equipment. Even the research studies were being planned prior to the opening of the lab and some projects began as early as June 1998.

Researchers

Blake Papsin heads the Cochlear Implant Laboratory. He has a long-standing interest in behavioral measures of auditory function dating back to his Masters degree in psychoacoustics. As an accomplished musician, he has a natural interest in understanding how children with hearing loss are able to develop an appreciation of music through the use of a cochlear implant. He is also keen to develop behavioral measures of music perception which could tell us how well a child is developing auditory skills using his or her implant.

Robert Harrison is the Senior Scientist on the Cochlear Implant Team and directs the Auditory Science Laboratory at The Hospital for Sick Children. With his experience and well recognized reputation for work in basic science of the auditory system, Dr. Harrison is a valuable resource for the implant lab and acts as a supervisor for much of the work done. Dr. Harrison's work in animal models has shown that the auditory system will become reorganized based on the stimulation or lack of stimulation received and that these effects are most prevalent in early development. This implies that the auditory system can respond to the stimulation from a cochlear implant

Karen Gordon is a Ph.D. who now directs research based at the Cochlear Implant Laboratory.  She is studying auditory development in children using unilateral and bilateral cochlear implants.  She has worked as a clinical audiologist both on the Cochlear Implant Team and in the Audiology Clinic at The Hospital for Sick Children prior to beginning her research work.  

Areas of Study

As a paediatric centre we are focusing on questions about development of hearing in children with hearing loss as a result of cochlear implant(s). We are studying auditory development in many different ways. Projects focus on the neurological development and function of the auditory system,development of hearing skills, development of speech perception, and development of speech and language production following cochlear implantation. Click here for more details about neurological function and development of the auditory system in cochlear implant users.

We are also investigating some of the many factors which might affect auditory development after cochlear implantation including genetic origins of hearing loss, anatomical and physiological differences in the auditory system, and psycho-social issues to name a few. We are also working on more efficient ways to program the implant through the use of new tests which record activity from the auditory system. These tests, called objective measures, can limit the amount of reactions that the child needs to make which may make programming sessions shorter and easier. This will be particularly important for very young children.

Funding and Donations 

Support and funding for research is critical to maintaining our high level of activity in the Cochlear Implant Laboratory. The Laboratory was established due to support from The Hospital for Sick Children's Research Institute. Ongoing work has been supported by research grants awarded by the Canadian Institutes of Health Research, The Hearing Foundation of Canada, the SickKids Foundation, and the Ontario Physicians' Services Incorporated Foundation. Dr. Papsin currently holds the Chair in Auditory Development Research which was funded by a generous donation from Cochlear Corporation.

We have also been very fortunate to receive important donations from a number of families in our cochlear implant community. We are also most appreciative of the support shown by the many families and their children who contribute their valuable time and considerable effort to our research endeavors.