Multivariate prediction of conductive dysfunction in well and NICU newborns using wideband acoustic immittance with...

The goal of newborn hearing screening is to detect permanent congenital hearing loss. However, the high incidence of middle ear fluid and debris in the ear canal at birth results in only a 5-10% positive predictive value, thus requires repeated screening, and can delay or complicate diagnosis of permanent hearing loss. The overall goal of this study was to assess tympanometric and ambient wideband acoustic immittance (WAI) tests and wideband acoustic reflex thresholds (ART) in well-baby and newborn intensive care (NICU) cohorts with four specific objectives: 1) Assess predictive accuracy of WAI and ART for ears referring on the first or second stages of newborn hearing screening; 2) Identify inadequate tests likely due to probe blockages or leaks; 3) Assess prediction models separately for well-baby and NICU screening outcomes; and 4) Assess prediction models relative to confirmed hearing status determined by diagnostic follow-up auditory brainstem response (ABR).

Prospective, observational study of full-term (n = 514) and premature newborns (n = 239) recruited from well-baby and NICU nursery birth hospital newborn hearing screening program. Wideband tympanometry, ambient absorbance, and acoustic reflexes were tested after Stage 1 transient otoacoustic emissions (TEOAE) screening. The reference standard for Pass or Refer groups was initially defined on the stage 1 TEOAE test result. Pass or Refer groups were then reassigned based on the stage 2 screening ABR for those who referred at Stage 1, and all NICU infants. Multivariate models were developed using reflectance and admittance variables to predict screening referral relative to the screening reference standard in a randomized sub-group of subjects at Stage 1 and Stage 2 screening. Classification accuracy was evaluated on a second, independent sub-group. Individual tests were classified as having inadequate probe fits if they had excessively low values of sound pressure level or susceptance (leak) or absorbance (blockage). WAI prediction models were then assessed relative to hearing status determined with diagnostic ABR in a subset of infants that returned for follow-up.

Differences in ambient absorbance for Pass v. Refer screening groups revealed the greatest differences and effect sizes occurring in frequency bins between 1.4-2 kHz. Screening failure at both Stage 1 and 2 was most accurately predicted by models using ambient absorbance and power level variables at frequencies between 1-2.8 kHz, including ARTs. Tympanometric admittance variables at the positive-pressure tail for frequencies between 1-2.8 kHz in combination with the ART were more accurate predictors than those at peak pressure or the negative-pressure tail. Multivariate models generalized well to an independent group of infants at both Stage 1 and 2 for both the ambient and tympanometric models. Ambient tests revealed more inadequate tests than tympanometric tests, primarily due to blocked probe tips. Exclusion of ears to detect probe leaks or blockages slightly improved the ambient prediction models, but did not affect tympanometric models. Follow-up diagnostic ABR testing showed significant predictive ability for WAI to detect conductive hearing loss based on screening results.

Predictive accuracy of ambient and tympanometric absorbance was highest with inclusion of wideband acoustic reflex tests.. Multivariate prediction models developed for WAI tests were repeatable in an independent group, and for well and NICU infants. Detection of probe blockage or leaks improved prediction for ambient measures. Use of WAI at Stage 1 screening has high positive predictive value (89%) for ears with transient or persistent outer or middle ear problems. Prediction of conductive hearing loss diagnosed with follow-up air and bone conduction ABR provides validation of wideband tests for use in newborn hearing screening programs.