title: Chirp-evoked otoacoustic emissions in children.
abstract: OBJECTIVE
  The purpose of the study was to investigate the properties of otoacoustic emissions (OAEs) evoked by chirp stimuli and compare them with standard click-evoked OAEs. Differences between evoked OAEs in children with and without spontaneous otoacoustic emissions (SOAEs) were also assessed.
  
  
  METHODS
  OAEs were first recorded from 54 children (age 4-10 years) in a screening setup. In each ear five OAE measurements were made using two types of chirps (7.5 ms and 10.5 ms) at around 70 dB pSPL; clicks at 70 and 80 dB pSPL; and a standard synchronized SOAE stimulation protocol. Tympanometry was also conducted. Pass/refer criteria based on signal to noise ratios (SNRs) were applied to all OAEs. Pass/refer rates from all methods (OAEs evoked by chirps and clicks, and tympanometry) were compared. Additionally, half-octave-band values of OAE SNRs and response levels were used to assess statistical differences.
  
  
  RESULTS
  Chirp-evoked OAEs generated a similar number of passes to click-evoked OAEs when the same level of stimulus was used. When using lower stimulus levels, both chirp- and click-evoked OAEs diagnosed nearly all ears that failed tympanometry. The response levels and SNRs of OAEs evoked by clicks and chirps were very similar. The highest response levels were in the 1.4 kHz half-octave band. The SNRs for ears with SOAEs were highest at 1.4 kHz, whereas they were at 4 kHz for ears without SOAEs. Both response levels and SNRs were higher by about 5 dB for ears with SOAEs than ears without SOAEs. Also all ears with SOAEs generated a pass result in screening, while ears without SOAEs gave a pass less frequently (at least 30% fewer cases).
  
  
  CONCLUSIONS
  The results suggest that performance of chirp-evoked OAEs for screening purposes is similar to click-evoked OAEs when the same stimulus level is applied. OAEs evoked with lower stimulus levels (70 vs. 80 dB pSPL) are more sensitive to middle ear pathology. The presence of SOAEs significantly influences the pass rates of OAEs evoked by chirps and clicks.
authors.affiliation: Institute of Physiology and Pathology of Hearing, ul. Zgrupowania AK Kampinos 1, 01-943 Warszawa, Poland. w.jedrzejczak@ifps.org.pl
authors.forename: W Wiktor
authors.initials: WW
authors.lastname: Jedrzejczak
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kochanek
authors.forename: Lech
authors.initials: L
authors.lastname: Sliwa
authors.forename: Edyta
authors.initials: E
authors.lastname: Pilka
authors.forename: Anna
authors.initials: A
authors.lastname: Piotrowska
authors.forename: Henryk
authors.initials: H
authors.lastname: Skarzynski
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods*; D001309:Auditory Threshold / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006311:Hearing Disorders / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011044:Poland; D012016:Reference Values; D012424:Rural Population; D012572:School Health Services; D059629:Signal-To-Noise Ratio