Hearing Loss, Prognosis, and Long-Term Impact of Otitis Media with Effusion in Children - PROJECT SUMMARY/ABSTRACT Otitis media with effusion (OME) is a common childhood condition characterized by a non-purulent effusion in the middle-ear space. OME can cause conductive hearing loss (CHL), but hearing status varies substantially from normal hearing to moderate hearing losses (0-55 dB HL), and episodes of OME can last for variable lengths of time. Clinical equipoise exists as to whether to treat OME (i.e., surgical tube placement) or wait for it to resolve spontaneously. While there are risks associated with surgery in young children, waiting for OME to resolve spontaneously may also carry risks. OME has been associated with long-term deficits in speech, language, and auditory processing. However, findings from clinical studies are variable, resulting in a persistent debate regarding the long-term sequelae of OME. We hypothesize that a key risk factor for long-term deficits is the cumulative auditory deprivation associated with OME-related CHL, not by the presence of OME itself. If this is the case, only a subset of children with OME (those with notable hearing losses) would be at risk of long-term deficits. As such, it is critical that we determine the hearing status of all children with OME as well as understand the variability in the effects of this hearing loss on long-term outcomes as a function of the degree and symmetry of the loss. While current diagnostic tools can often indicate the presence or absence of OME, there are significant limitations in our ability to determine the presence, degree, and symmetry of the CHL associated with OME due to the challenges with behavioral audiological testing in young children, and no objective alternative to behavioral testing currently exists. Further, even in cases where hearing status can be determined behaviorally, determination of hearing at one time point does not indicate the stability of hearing thresholds or the risk and magnitude of long-term deficits. Our long-term goal is to address these knowledge gaps comprehensively to refine clinical practice guidelines by identifying children most at risk for long-term deficits to improve treatment recommendations. As a first step, the primary objective of this proposal is to improve the diagnosis and understanding of OME and its related hearing loss and investigate the influence of variability in cumulative auditory deprivation on one sequela of OME, binaural processing. In Aim 1, we will develop a non-invasive objective estimate of hearing loss due to OME. In Aim 2, we will characterize the short-term stability and persistence of OME and its related hearing loss and determine the prognostic value of a non-invasive measure of middle-ear mechanics. In Aim 3, we will determine the influence of OME-related variations in CHL and middle- ear mechanics on individual differences in binaural processing. Completion of these Aims will achieve a first step toward our long-term goal of understanding the consequences of OME and developing tools to identify children most at risk for negative sequelae by both improving our ability to objectively determine prognosis and hearing status over time and improving our understanding of how these factors contribute to individual variability in long- term outcomes.