Spotlight on Melissa Polonenko: Listening & Learning about Audiology Research
By: Arpita Parmar
Melissa Polonenko, an audiologist and PhD candidate at the Institute of Medical Science (IMS), comments on her journey as a clinician-scientist with an insatiable curiosity for research.
Melissa began her training as an undergraduate student at the University of Western Ontario, where she completed a degree in Medical Sciences with specializations in physiology and biochemistry. Inspired by an undergraduate psychology course on human sensation and perception, she decided to volunteer at the National Centre for Audiology (NCA), where research in both basic science and clinical hearing is conducted. At the NCA, she worked in multiple audiology clinics. But, her interest in pediatric populations made the Child Amplification Lab most memorable. In explaining her interest, she says, “Hearing is very important in children, especially in the early years as it strongly linked to speech and language development.”
After her initial experience in audiology, Melissa decided to pursue a Master’s degree in audiology and gain more clinical experience as an audiologist at the Glenrose Rehabilitation Hospital in Edmonton, Alberta. She was excited about the big move out west, where she could pursue her outdoor hobbies of hiking, outback camping, and whitewater rafting in addition to being surrounded by the Canadian Rockies. At the Glenrose Rehabilitation Hospital, Melissa’s patients ranged from babies to adults. Working in a multi-disciplinary team, her roles included diagnosing hearing loss, managing hearing aids, providing patient care through telehealth, conducting hearing, vestibular, and evoked potential tests as well as adult cochlear implant candidacy assessments. After three years of being fully immersed in a clinical setting, Melissa decided to shift her focus to research and embark on a journey as an audiologist-scientist.
Melissa decided to move back to Ontario to complete her doctoral training at the IMS, “Toronto is a clinical research powerhouse. There is plentiful stimulating research happening in one concentrated area.” She currently works under the supervision of Dr. Karen Gordon, an IMS faculty member that is also an audiologist by training. In explaining her choice, Melissa states, “The IMS [is] an ideal fit for someone training as a clinician-scientist.” To support her learning and help contextualize her research more broadly, Melissa is also enrolled in the Collaborative Program in Neurosciences (CPIN).
At the Hospital for Sick Children (SickKids), Melissa is a part of an inter-disciplinary team of otolaryngologists and audiologists within the cochlear implant program. She collaborates on several unique clinical projects that aim to integrate both clinical and basic research in audiology to augment patient outcomes. This is, in part, an ongoing goal of her research that focuses on how asymmetric hearing, or differences in hearing ability across one’s ears, affects brain development. “Back in the day, if you were bilaterally deaf (deaf in both ears), you would only get one implant. The problem with this is that your brain reorganizes to preferentially respond to sounds from the one ear in which you have hearing.” However, the ability to hear with both ears is imperative, particularly in children. They are most vulnerable to the adverse effects of asymmetric hearing due to the influence of hearing on brain and psychosocial development.
Melissa explains that relative to those with bilateral hearing, children who are only able to hear through one ear have impaired school performance. This is in part due to their effort in trying to hear what is being said rather than learning and understanding the message being communicated. Dr. Gordon’s research recommends giving bilateral implants to pediatric patients at the same time or at least 1.5 years apart. Staying within this time is necessary for the implants to facilitate bilateral auditory development. “If a second implant is given to a teenager who has experienced years [of unilateral deafness], the brain will respond abnormally to the sounds being heard from the new cochlear implant—as if it doesn’t know what the sound is, (since) it has been deprived for so long,” Melissa explained. Their ongoing research has contributed to Sick Kids refining their criteria when determining which children can receive a cochlear implant.”
As part of her thesis, Melissa studies the changes occurring in children with unilateral deafness after receiving a cochlear implant in the impaired ear. She is interested in how the cochlear implant, which sends electric pulses that stimulate the cochlear nerve, integrates acoustic hearing from the ear without a cochlear implant. More importantly, she desires to identify how this combined electro-acoustic hearing affects various outcomes, such as brainstem and cortical development, speech, behavior, and even music perception. Melissa’s project started off with 10 children, but now has over 100 participants. As Melissa’s research indicates that bilateral hearing in early childhood affects the mapping of auditory input in the brain and influences the development of speech, language as well as balance, she now studies how brains accept and integrate hearing from pairs of cochlear implants after initially experiencing unilateral deafness. When reviewing her research experience at Sickkids, Melissa highlights the gift of having an ethnically diverse and clinically heterogeneous study population. In addition, as she follows the development of these children over several years, Melissa has a gratifying and rewarding opportunity to see how things change (and improve) over time. She comments, “The families are very grateful for our program at SickKids and tell us how much their child loves their new implant.”
Melissa also explains how her clinical experience as an audiologist, prior to pursuing her PhD, was very helpful. It let her apply technical expertise and knowledge of clinical assessment tools to inform the direction of her research. Additionally, she describes the immense value of having worked with families and children in her past, as “knowing how to interact with children can make or break data collection in pediatric research.” Furthermore, when asked about her advice to future and current graduate students, Melissa stresses the importance of being open-minded and exploring different possibilities: “Always ask questions, you never know what you will discover. And don’t be afraid to put the work in.”