BMC Ear, Nose and Throat Disorders

Background: Tone-burst otoacoustic emissions (TBOAEs) have not been routinely studied in pediatric populations, although tone burst stimuli have greater frequency specificity compared with click sound stimuli. The present study aimed (1) to determine an appropriate stimulus level for neonatal TBOAE measurements when the stimulus center frequency was 1 kHz, (2) to explore the characteristics of 1 kHz TBOAEs in a neonatal population. Methods: A total of 395 normal neonates (745 ears) were recruited. The study consisted of two parts, reflecting the two study aims. Part I included 40 normal neonatal ears, and TBOAE measurement was performed at five stimulus levels in the range 60–80 dB peSPL, with 5 dB incremental steps. Part II investigated the characteristics of the 1 kHz TBOAE response in a large group of 705 neonatal ears, and provided clinical reference criteria based on these characteristics. Results: The study provided a series of reference parameters for 1 kHz TBOAE measurement in neonates. Based on the results, a suggested stimulus level and reference criteria for 1 kHz TBOAE measures with neonates were established. In addition, time-frequency analysis of the data gave new insight into the energy distribution of the neonatal TBOAE response. Conclusion: TBOAE measures may be a useful method for investigating cochlear function at specific frequency ranges in neonates. However, further studies of both TBOAE time-frequency analysis and measurements in newborns are needed. Background Click evoked otoacoustic emissions (CEOAEs), as one type of transient evoked otoacoustic emission (TEOAE), have been widely used to assess the functioning of cochlear outer hair cells. Since the CEOAE click stimulus has a broad spectrum, and consequently can stimulate a broad frequency region of the cochlea in a single measurement, CEOAE measurement has been especially applied as a general tool in universal neonatal hearing screening (UNHS) programs. Another type of TEOAE – tone burst evoked OAEs (TBOAEs) – uses narrow bandwidth tone stimuli. This allows stimulus energy to be concentrated on a particular area of the basilar membrane and elicits a more frequency-specific cochlear response [1,2]. Fourier analysis of TBOAEs indicates that emission spectra are similar to that of the tone burst stimulus [3-5]. As to the Published: 17 April 2008 BMC Ear, Nose and Throat Disorders 2008, 8:3 doi:10.1186/1472-6815-8-3 Received: 29 November 2007 Accepted: 17 April 2008 This article is available from: http://www.biomedcentral.com/1472-6815/8/3 © 2008 Zhang et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.