Audiological Rehabilitation of Children With Unilateral Hearing Loss

More than 5 million children in the United States have hearing loss in one ear, known as unilateral hearing loss (UHL). The primary consequence of UHL is reduced spatial hearing, which is crucial for communication and functioning in everyday listening conditions. Children with UHL (CUHL) are at risk for delays in language and academic outcomes compared to peers with normal hearing in both ears. However, there are large individual differences in developmental outcomes that cannot be explained by the degree of hearing loss in the affected ear. CUHL also have a wide range of spatial hearing abilities, and there is currently limited evidence to link individual differences in spatial hearing to the wide range of developmental outcomes that are observed in CUHL. The lack of predictable patterns of risk for CUHL leads to inconsistent recommendations for audiological intervention or intervention that commences only after a child demonstrates fails to progress in language or academic outcomes. Audiologists have the option to improve spatial hearing in CUHL through fitting a hearing aid on the affected ear, but hearing aids are often not provided or are only provided at later ages, even when UHL is identified in the first few months of life. The lack of consistent practices around provision of hearing aids for CUHL is due to limited evidence that hearing aids can support binaural processing in CUHL. This project seeks to provide mechanistic evidence to support earlier and more timely intervention for CUHL. Researchers will use a metric referred to as auditory dosage to quantify auditory input to the affected ear based on aided and unaided speech audibility and consistency of hearing aid use. Auditory dosage is expected to be the primary predictor of individual differences in outcomes for CUHL. The core hypothesis of the proposal is that CUHL who have higher auditory dosage in their affected ear will have better spatial hearing, which in turn leads to better language and academic outcomes than peers with lower auditory dosage in their affected ear. Experiments will combine behavioral and neuroimaging measures of spatial hearing with and without amplification to assess how auditory dosage in the affected ear influences spatial hearing, language, and academic outcomes in CUHL. Researchers will analyze the effects of hearing aid distortion and auditory dosage on behavioral measures of spatial hearing with and without amplification. Structural and functional neuroimaging, including magnetoencephalography and magnetic resonance imaging, will be used to assess the impact of auditory dosage on spatial hearing in CUHL. The study will use an accelerated longitudinal design to assess the mediating effects of spatial hearing on the association between hearing aid distortion and auditory dosage and language and academic outcomes in CUHL. These experiments will provide mechanistic evidence to help guide decisions about audiological intervention for CUHL and lead to individualized interventions to improve spatial hearing, language, and academic outcomes for CUHL.