title: Low-frequency otoacoustic emissions in schoolchildren measured by two commercial devices.
abstract: OBJECTIVE
  Click evoked otoacoustic emissions in children are known to be good indicators of hearing function when used in the frequency range 1.5-4 kHz. Using two commercial devices, the present study investigates the usefulness of responses in the lower frequency range of 0.5-1 kHz evoked by 0.5 kHz tone bursts.
  
  
  METHODS
  Otoacoustic emissions (OAEs) were recorded from the ears of 37 schoolchildren (age 12-13 years). OAE measurements were then made using two devices: the ILO 292 (Otodynamics) and the HearId (Mimosa Acoustics). Each device was used for two measurements: first with a standard click stimulus at 80 dB pSPL (CEOAEs) and a second using a 0.5 kHz tone burst at 80 dB pSPL (TBOAEs). Pure tone audiometry and tympanometry were also conducted. Half-octave-band values of OAE signal to noise ratios (SNRs) and response levels were used to assess statistical differences.
  
  
  RESULTS
  Both devices provided similar SNR results for click and tone burst stimuli, although the ILO device generated slightly higher response levels for clicks. For the 0.5 kHz tone bursts, both devices evoked very weak responses at 0.5 kHz and the peak response occurred at 0.7-1 kHz. Generally, CEOAE SNRs were about 10 dB in the 1-4 kHz range, while SNRs for 0.5 kHz TBOAEs were about 10 dB at 0.7-1 kHz.
  
  
  CONCLUSIONS
  0.5 kHz TBOAEs could be measured in children as effectively as CEOAEs. They can provide additional information about the 0.7-1 kHz frequency range, a range over which CEOAEs do not usually contain responses above the noise floor. The main difficulty was that the maxima of the 0.5 kHz TBOAEs occurred at frequencies of 0.7-1 kHz, probably because of spectral splatter from the short tone burst stimulus and from rapidly falling responses of the cochlea and the recording system at low frequencies.
authors: Institute of Physiology and Pathology of Hearing, ul. Mochnackiego 10, 02-042 Warszawa, Poland; World Hearing Center, ul. Mokra 17, Kajetany, 05-830 Nadarzyn, Poland. Electronic address: w.jedrzejczak@ifps.org.pl.
authors: W Wiktor
authors: WW
authors: Jedrzejczak
authors: Anna
authors: A
authors: Piotrowska
authors: Krzysztof
authors: K
authors: Kochanek
authors: Lech
authors: L
authors: Sliwa
authors: Henryk
authors: H
authors: Skarzynski
mesh_terms: D000158:Acoustic Impedance Tests / Q000295:instrumentation* / Q000379:methods; D000293:Adolescent; D001301:Audiometry, Pure-Tone / Q000295:instrumentation* / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology*; D002648:Child; D004867:Equipment Design; D004869:Equipment Safety; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011044:Poland; D011237:Predictive Value of Tests; D012572:School Health Services; D013334:Students / Q000706:statistics & numerical data
keywords: CEOAE; HearID; ILO; Otoacoustic emissions; Schoolchildren; TBOAE; Tone burst