title: Tone burst evoked otoacoustic emissions in different age-groups of schoolchildren.
abstract: BACKGROUND
  Otoacoustic emissions (OAEs) are believed to be good predictors of hearing status, particularly in the 1-4kHz range. However both click evoked OAEs (CEOAEs) and distortion product OAEs (DPOAEs) perform poorly at 0.5kHz. The present study investigates OAEs in the lower frequency range of 0.5-1kHz evoked by 0.5kHz tone bursts (TBOAEs) in schoolchildren and compares them with emissions evoked by clicks.
  
  
  METHODS
  Measurements were performed for two groups of normally hearing schoolchildren. Children from 1st grade (age 6-7 years) and children from 6th grade (age 11-12 years). Tympanometry, pure tone audiometry, and OAE measurements of CEAOEs, 0.5kHz TBOAEs, and spontaneous OAEs (SOAEs) were performed. Additionally, analysis by the matching pursuit method was conducted on CEOAEs and TBOAEs to assess their time-frequency (TF) properties.
  
  
  RESULTS
  For all subjects OAEs response levels and signal to noise ratios (SNRs) were calculated. As expected, CEOAE magnitudes were greatest over the range 1-4kHz, with a substantial decrease below 1kHz. Responses from the 0.5kHz TBOAEs were complementary in that the main components occurred between 0.5 and 1.4kHz. In younger children, TBOAEs had SNRs 4-8dB smaller in the 0.5-1.4kHz range. In addition, CEOAEs had lower SNRs in the 0.7-1.4kHz range, by 3-5dB. TBOAEs in younger children had maximum SNRs shifted toward 1-1.4kHz, whereas in older children it was more clearly around 1kHz. The differences in response levels were less evident. The presence of SOAEs appreciably influenced both CEOAEs and TBOAEs, and TF properties of both OAEs did not differ significantly between grades.
  
  
  CONCLUSIONS
  TBOAEs evoked at 0.5kHz can provide additional information about frequencies below 1kHz, a range over which CEOAEs usually have very low amplitudes. The main difference between the two age groups was that in older children CEOAEs and 0.5kHz TBOAEs had higher SNRs at 0.5-1.4kHz. Additionally, for ears with SOAEs, 0.5kHz TBOAEs had higher response levels and SNRs similar to CEOAEs.
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: 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: Edyta
authors.initials: E
authors.lastname: Pilka
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; Heart Failure and Cardiac Rehabilitation Department of the Medical University of Warsaw, Warsaw, Poland; Institute of Sensory Organs, ul. Mokra 1, Kajetany, 05-830 Nadarzyn, Poland.
authors.forename: Piotr H
authors.initials: PH
authors.lastname: Skarzynski
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: Lukasz
authors.initials: L
authors.lastname: Olszewski
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: D000158:Acoustic Impedance Tests; D000161:Acoustic Stimulation / Q000379:methods*; D000367:Age Factors; D001301:Audiometry, Pure-Tone; D002648:Child; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D012016:Reference Values; D059629:Signal-To-Noise Ratio
keywords: Click evoked otoacoustic emissions; OAE; Schoolchildren; Spontaneous otoacoustic emissions; Tone burst evoked otoacoustic emissions; Transiently evoked otoacoustic emissions