Research Grants in Hearing and Balance Winners 2021

Abstract: Most children with hearing loss are educated in mainstream classrooms and continue to lag their peers with normal hearing in areas of academic and psychosocial development. It is well-known that classrooms are busy environments filled with competing noise, reverberation, and distracting events. Although the influence of competing noise and reverberation on speech perception of children with hearing loss has been studied extensively, it is unknown how distraction-related attention shifts influence successful communication. This is a significant gap in our understanding of the mechanisms that underly successful communication in complex environments, particularly considering that children with hearing loss orient their attention to unexpected events in the classroom more than twice as much as children with normal hearing.

In this study, we will implement a previously established listening effort paradigm in listening conditions that include repeated auditory distractors. This paradigm will measure the consequences of auditory distraction on speech recognition and listening effort. The proposed work will first validate this paradigm in young adult listeners in normal hearing before applying them to the study of developing listeners with and without hearing loss.

Abstract: The World Health Organization (WHO) and other non-governmental organizations have ongoing public awareness campaigns promoting the use of highly active antiretroviral therapy (HAART) in pregnant and nursing mothers to prevent the transmission of human immunodeficiency virus (HIV) to their children.

Previous studies that indicated harm to the fetus due to a particular drug used in HAART led to a change in WHO guidelines for pregnant and nursing mothers, but no studies to date have analyzed the effect of these drugs on the developing auditory system, despite studies that indicate that in utero exposure to these drugs can cause mitochondrial damage that impacts the highly-energy-consumptive cochlea.

This study aims to investigate the in-utero effects of currently recommended HAART drug cocktails on auditory physiology and how those drugs interact with other known ototoxins such as noise and aminoglycoside antibiotics.

Abstract: Vestibular impairments are identified through measures of vestibular reflexes such as the vestibulo-ocular reflex (VOR). However, the extent of impairment observed through the VOR may not correlate with how patients subjectively experience their symptoms. Perception of vestibular stimuli has been previously studied with a large focus on perceptual thresholds.

At threshold levels of motion, perception is more sensitive at higher frequencies, consistent with the VOR as a high-pass filter. The purpose of this study is to extend previous vestibular psychophysics work by measuring magnitude estimates of angular motion across a range of suprathreshold stimuli and compare perceptual measures to the VOR in a healthy population.

Vestibular stimulation will be provided with a rotary chair, and multiple experimental conditions of sinusoidal harmonic acceleration of varying frequencies, peak velocities, acceleration rates, and displacement will be used. The VOR will be recorded using videonystagmography (VNG) methods while participants provide magnitude estimates of both speed and angle of displacement.

We hypothesize that magnitude estimates will be consistent with a general model of logarithmic scaling according to Steven’s Power Law. Further, we hypothesize similar effects of frequency as observed in threshold studies and weak correlations between suprathreshold perception and physiologic measures of the VOR.