Longitudinal outcomes of distortion product otoacoustic emissions and wideband reflectance in infants

LONGITUDINAL OUTCOMES OF DISTORTION PRODUCT OTOACOUSTICEMISSIONS AND WIDEBAND REFLECTANCE IN INFANTSbyVIRGINIA RAMACHANDRANDecember 2012Co-Advisors: Dr. Jean E. Andruski and Dr. Kenneth R. BouchardMajor: Communication Sciences and DisordersDegree: Doctor of PhilosophyClinical practice has shown that some infants are born with, or develop atemporary conductive hearing loss characterized by the absence of measurableotoacoustic emissions (OAEs) but normal sensorineural hearing. This transient situationinterferes with the process of universal newborn hearing screening and identification.The purpose of this prospective, longitudinal study was to describe outcomes ofdistortion product OAE (DPOAE) screening in infants at birth, and one, four, eight, andtwelve weeks of age. In addition, wideband reflectance (WBR) measures, which havethe potential to help characterize outer-ear canal and middle-ear function, were examined to determine their potential utility in identifying DPOAE screening outcomes.Beginning with a sample of 50% of ears that passed the initial DPOAE screeningat birth, results showed that passing outcomes rose over the course of time, at rates of 72.1%, 84.6%, 86.0%, and 96.0% at weeks one, four, eight, and twelve, respectively.Rates of new fails – ears that had passed the screening at a previous time point – alsoincreased over time, with the exception of the last time point, at which no new failingoutcomes were seen. These data suggest that twelve weeks would be the most efficient