SPATIAL HEARING AND FUNCTIONAL AUDITORY SKILLS OF CHILDREN WHO HAVE UNILATERAL HEARING LOSS

Children with unilateral hearing loss (UHL) are at increased risk for a range of developmental difficulties and delays, but there is substantial variability in developmental outcomes among this population. One explanation for the deficits observed among this population is that children with UHL have a reduced ability to compare sounds arriving at the two ears, which is critical for spatial hearing. Few studies have investigated the specific nature of the spatial hearing deficits that children with UHL experience. Defining this population’s spatial hearing deficits is critical for understanding and remediating the factors that contribute to the marked differences in developmental outcomes observed among children with UHL. The goal of this dissertation was to clarify the spatial hearing deficits experienced by children with UHL in natural listening environments. This goal was accomplished in two experiments under the following specific aims: (1) evaluate the effect of UHL on children’s ability to benefit from spatial separation of target and masker stimuli (spatial release from masking, SRM) for speech recognition in two-talker speech and speech-shaped noise, (2) assess localization on the azimuthal plane, and (3) determine the association between SRM and functional listening abilities as assessed by parent report for children with UHL. The first experiment addressed Aim 1 in a group of school-age children and adults with normal hearing who completed the experiment both with and without an acute simulated conductive UHL. The second experiment addressed Aims 1 through 3 in a group of children with longstanding sensorineural or mixed UHL, age-matched peers with normal hearing, and adults with normal hearing. Results from Aim 1 suggest that the real-world spatial hearing deficits resulting from UHL depend on the UHL type, degree, and/or duration, as well as characteristics of the listening environment. Findings from Aim 2 provide new insight into the spatial hearing cues used by children with UHL to localize sounds. Under Aim 3, results suggest that parent report of children’s functional hearing is associated with SRM for children with UHL. The findings from this dissertation provide a basis for our understanding of the deficits and individual differences observed in children with UHL.Doctor of Philosoph