title: Otoacoustic emissions in newborns evoked by 0.5kHz tone bursts.
abstract: BACKGROUND
  Otoacoustic emissions (OAEs) are currently widely used in newborn hearing screening programs. OAEs evoked by transients (TEOAEs) in newborns are usually characterized by large response levels at higher frequencies but lower frequencies are affected by physiological noise. The purpose of the present study was to acquire responses at lower frequencies by measuring OAEs evoked by 0.5kHz tone bursts (TBOAEs).
  
  
  METHODS
  Otoacoustic emissions (OAEs) were recorded from 49 newborns. Measurements were made using the ILO 292 equipment from Otodynamics. In each ear, three measurements were made: first with a standard click stimulus at 80dB pSPL (CEOAEs), a second using a 0.5kHz tone burst at 80dB pSPL (TBOAEs), and a third recording of spontaneous OAEs (SOAEs). Global and half-octave-band values of OAE signal-to-noise ratio (SNR) and response level were used to assess statistical differences between CEOAEs and 0.5kHz TBOAEs. Additionally, time-frequency (TF) analysis of signals was performed using the matching pursuit method.
  
  
  RESULTS
  Global levels were highest for CEOAEs. However, at low frequencies (0.7-1kHz), 0.5kHz TBOAEs had significantly higher levels and SNRs than CEOAEs. At these frequencies, SNRs of CEOAEs were usually below 0dB. At 0.5kHz there were no statistically significant differences between CEOAEs and TBOAEs. In ears with recordable SOAEs, CEOAEs and TBOAEs had higher levels and SNRs than in ears without SOAEs.
  
  
  CONCLUSIONS
  Use of 0.5kHz TBOAEs may be a useful addition to standard CEOAE tests in newborns. They provide information about lower frequencies, a region where CEOAEs are usually prone to noise. The presence of SOAEs affects the magnitudes of both CEOAEs and TBOAEs.
authors.affiliation: Institute of Physiology and Pathology of Hearing, ul. M. Mochnackiego 10, 02-042 Warsaw, Poland; World Hearing Center, ul. Mokra 17, Kajetany 05-830 Nadarzyn, Poland. Electronic address: w.jedrzejczak@ifps.org.pl.
authors.forename: W Wiktor
authors.initials: WW
authors.lastname: Jedrzejczak
authors.affiliation: Department of Otolaryngology Polish Mother's Memorial Hospital-Research Institute Medical University of Lodz, ul. Rzgowska 281/289, 93-338 Lodz, Poland.
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Konopka
authors.affiliation: Institute of Physiology and Pathology of Hearing, ul. M. Mochnackiego 10, 02-042 Warsaw, Poland; World Hearing Center, ul. Mokra 17, Kajetany 05-830 Nadarzyn, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kochanek
authors.affiliation: Institute of Physiology and Pathology of Hearing, ul. M. Mochnackiego 10, 02-042 Warsaw, Poland; World Hearing Center, ul. Mokra 17, Kajetany 05-830 Nadarzyn, Poland.
authors.forename: Henryk
authors.initials: H
authors.lastname: Skarzynski
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening / Q000379:methods; D017084:Otoacoustic Emissions, Spontaneous; D059629:Signal-To-Noise Ratio; D013016:Sound
keywords: CEOAE; Newborns; SOAE; TBOAE; TEOAE