Ruth Litovsky, PhD – Slide of the Week

Ruth Litovksy, PhD - Slide of the Week

Title: Evaluating the impact of age, acoustic exposure, and electrical stimulation on binaural sensitivity in adult bilateral cochlear implant patients

Citation: Thakkar, T., Anderson, S., Kan, A., & Litovsky, R.Y. (2020) Evaluating the Impact of Age, Acoustic Exposure, and Electrical Stimulation on Binaural Sensitivity in Adult Bilateral Cochlear Implant Patients. Brain sciences, (invited paper in special issue on Neuroplasticity:, under review)

Abstract: Background: Cochlear implants are provided to people with significant hearing loss, in order to promote communication using oral language. Two (bilateral) implants are provided to promote sound localization and speech understanding in noise. Study Motivation: To understand the impact of age at onset of deafness on binaural hearing sensitivity, so that the window of plasticity can be considered when providing treatment options to patients. Methods: Recruit patients with onset of deafness varying from early childhood to late adulthood. Deliver electrically pulsed stimuli directly to the cochlear electrode arrays, synchronized in the two ears. Measure sensitivity to interaural differences in time (binaural sensitivity). Results: Onset of deafness prior to 18 years of age leads to worse binaural hearing sensitivity (higher thresholds) compared with onset ages 18 years or older. Conclusion: The fact that cochlear implant patients have worse binaural hearing if they became deaf during childhood suggests that deprivation of normal acoustic inputs early in life compromises the ability of the brain to learn to use auditory cues that are important for everyday function such as sound localization.

About the Lab: Research in the Litovsky lab focuses on the ability of children and adults to hear in complex auditory environments (e.g., classrooms, restaurants, playgrounds, and “cocktail parties”). We are typically faced with the challenge of interpreting sounds as they reach the ears, learning to ignore echoes and other irrelevant, distracting signals. The brain has specialized circuits that compute sound location and separate important sounds from background noise. We study the contribution of binaural hearing and the limitations that are experienced by people with hearing loss. In particular, we focus on a unique population of people who are deaf and use cochlear implants. In addition to studying spatial hearing, such as sound localization skills and speech understanding in noise, we are interested in cognitive development and its implications for auditory processing. Another aspect of our research focuses on the effect that challenging listening situations has on listening effort, and the amount of cognitive load exerted during psychophysical testing. Finally, our reverse engineering approaches focus on possible ways in which bilateral cochlear implants can be improved by synchronizing the devices across the ears and utilizing novel strategies to stimulate electrodes in the cochlea that restore near-normal binaural hearing.

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