Tympanometry in newborn infants--1 kHz norms.

With the rapid implementation of universal newborn hearing screening (UNHS) programs, a test of middle-ear function for infants is urgently needed. Recent evidence suggests that 1 kHz tympanometry may be effective. Normative data are presented for newborn intensive care unit (NICU) graduates tested at a mean age of 3.9 weeks (Study 1) and full-term infants tested at 2-4 weeks (Study 2) who passed an otoacoustic emissions (OAE) screen. Nearly all infants tested had single-peaked tympanograms. The norms are evaluated for a group of full-term infants who were screened with OAE (Study 3) and two groups of infants (NICU patients and well babies) who were not screened by OAE (Study 4). The 5th percentile for static admittance for NICU and full-term babies was identical, allowing a sinngle pass-fail criterion. Using that criterion, well babies who passed an OAE screen (Study 3) yielded a 91% pass rate. Those who passed the OAE screen had substantially higher 1 kHz static admittance than those who failed, suggesting a strong relationship between middle-ear transmission characteristics and OAE responses. The pass rate was lower for newborn well babies and NICU graduates who were not screened by OAE (Study 4).