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Can you tells us how you ended up in such an offbeat, unconventional and unusual career?
As a kid, I always wanted to learn more about sound and the hearing sense. One of my closest friends at the time had a hearing impairment and that triggered my fascination to learn more about how the auditory system worked. I started out by pursuing my undergraduate degree (Bachelors in Audiology and Speech Language Pathology) at Ali Yavar Jung National Institute for the Hearing Handicapped, Mumbai in 2009.
What did you do next?
My undergraduate degree exposed me to an incredible case load but I knew that at some point down the road, I wanted to look into aspects of hearing loss beyond a clinical perspective to truly understand auditory functioning. I went on to enroll in a Master’s degree in Audiological science at the Ear institute at University College London (UCL). The Ear Institute is an interdisciplinary research institute where the research revolves around understanding hearing but the techniques span across the fields of genetics, cell biology, neurophysiology, human perception, cognition and clinical trials. I appreciated the complexities of understanding auditory function and realized that compared to other senses like vision, the auditory system is relatively underexplored. Being exposed to such breadth in auditory research inspired me to think beyond traditional clinical audiology and got me further interested in exploring basic hearing processes. I wanted to get as much research experience as possible to help me decide what area of auditory research interested me the most and whether I wanted to switch from clinical work to basic research in auditory neuroscience.
Can you tell us about your research experience?
My first research experience was an 8 week internship at the University of Cambridge where we studied properties of complex pitch perception using frequency following responses (FFR)(1). I was thrown into the deep end of EEG data analysis which was a very steep learning curve. However, it was exciting to be investigating new research ideas and this experience essentially served a crash course in everything from experimental design to analysis and interpretation of data. Simultaneously, I also carried out my Master’s thesis project that studied the effects of aging on temporal fine structure perception(2). After these brief research experiences, I worked for a year at the Institute of Hearing Research in Nottingham on developing a platform for carrying out psychophysical tests of hearing in children with cochlear implants in clinics. It was an interesting experience as I had to collaborate with both clinicians as well as basic research investigators. I could draw upon my experience at that time for what could possibly be a feasible test setup for a busy clinic while trying to get clinicians to appreciate the need for more fine-grained assessment of cochlear implanted children. By this time, I had experienced three different research settings and three completely different auditory research fields and I recognized that I enjoyed investigating basic auditory phenomena using electrophysiological measures like EEG.
Tell us about your PhD?
I started my PhD in auditory neuroscience at the Ear Institute in 2011 studying the effect of attention on auditory scene analysis. It was a rapid learning experience of dealing with errors, careful assessment of the equipment and experimental paradigms and getting proficient with different programming platforms and analysis techniques, but being a part of such a dynamic research environment was exhilarating. In the second year of my PhD, I did a four month research project at the University of Maryland which ended up leading to the rest of my PhD project. I started investigating the ‘octave illusion’ which is an auditory illusion using stimuli very similar to ones used for studying scene analysis. Using EEG, we went on to test various aspects of the illusion that led to unexpected insights into how our auditory system processes sounds that occur simultaneously. My PhD proposed an alternative explanation for how the auditory system perceives this illusion. On the surface, exploring how an illusion is perceived sounds frivolous, but illusory percepts often tap into physiological processes that lead to understanding nuances of sensory systems. In auditory scene analysis, it is known that sounds that start and end at the same time are extremely difficult to parse apart. This binding phenomenon is known as temporal coherence. The octave illusion however, demonstrates a particular bilateral stimulus configuration, wherein binaural context and competition leads to the breakdown of these temporal coherence bonds. This particular property of the stimulus makes it very appealing to study in the context of coherence effects as well as bilateral context effects(3,4).
What did you do after Phd?
After my PhD, I decided that I wanted to explore a different field to augment my skill set and started a post-doctoral fellowship at the University of Minnesota. In my post-doc, I currently study fundamental characteristics of pitch perception and how that relates to pitch perception in cochlear implants. The spectral resolution of cochlear implants is currently insufficient to convey spectral pitch. It is also well known that contrary to speech perception, which implant users seem to do quite well in, melodic music perception is extremely poor with cochlear implants, even for extremely experienced implant users. With current advances in technology and different current focusing and steering paradigms being developed, there is a large emphasis on thinking that spectral pitch cues can be restored. Several studies have looked into the fundamental question of how many channels and how much current overlap can be tolerated when conveying pitch cues and have found that between 16-32 channels with modest amount of channel interaction should suffice. However, these studies have potential drawbacks due to poor control over the stimulus parameters. We are currently systematically addressing this important question using stringent vocoder studies in normal hearing individuals and we find that the parameters required to actually be able to use spectral cues far exceeds current day cochlear implant paradigms. Our results suggest that CIs, even with current focusing techniques such as partial tripolar stimulation, will not achieve the place specificity necessary to evoke a complex pitch. Instead, new approaches (including different implantation sites, such as the auditory nerve) may be necessary to improve the pitch perception experience by patients or to further improve techniques of providing temporal pitch cues to implant users. There is a persistent issue of a lack of understanding on both sides of the research spectrum; where basic researchers fail to communicate the importance of their work in a digestible fashion to the clinicians, who often feel like the problems their patients face are not addressed adequately. Having seen both sides, I appreciate clinical concerns and also believe that a mutually beneficial relationship can be formed by bridging this chasm. This is especially true in the field of cochlear implants where the need for well controlled basic research is of utmost importance to move modern day implants beyond the current status quo. I aspire to carry on with understanding how human hearing works and hope to incorporate invaluable clinical feedback into my research.