Access Type

Open Access Dissertation

Date of Award

January 2012

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Communication Sciences and Disorders

First Advisor

Jean A. Andruski

Second Advisor

Kenneth R. Bouchard

Abstract

Clinical practice has shown that some infants are born with, or develop a temporary conductive hearing loss characterized by the absence of measurable otoacoustic emissions (OAEs) but normal sensorineural hearing. This transient situation interferes with the process of universal newborn hearing screening and identification.

The purpose of this prospective, longitudinal study was to describe outcomes of distortion product OAE (DPOAE) screening in infants at birth, and one, four, eight, and twelve weeks of age. In addition, wideband reflectance (WBR) measures, which have the 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 screening at 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 - also increased over time, with the exception of the last time point, at which no new failing outcomes were seen. These data suggest that twelve weeks would be the most efficient time for re-evaluation of infants, and that four weeks would be an appropriate alternative.

Confidence intervals of reflectance measures were calculated for DPOAE outcomes at each time point. Reflectance outcomes were distributed such that fail and pass DPOAE outcomes could be predicted from the highest and lowest values, with an area of ambiguity in between. Receiver operating characteristic curves were calculated to determine the reflectance frequencies that would provide the highest predictive value at each time point. In addition, this method was used to determine how well WBR could be used to predict DPOAE outcomes at future time points. The predictive value of WBR for future DPOAE outcomes was poorer than concurrent prediction and likely has little clinical utility at present. However, low WBR values in the face DPOAE screening failures should cause concern for sensorineural hearing loss and can be used to prioritize such infants for follow-up audiologic evaluation.

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