Tone burst evoked otoacoustic emissions in different age-groups of schoolchildren W. Wiktor Jedrzejczak a,b, *, Edyta Pilka a,b , Piotr H. Skarzynski a,b,c,d , Lukasz Olszewski a,b , Henryk Skarzynski a,b a Institute of Physiology and Pathology of Hearing, ul. M. Mochnackiego 10, 02-042 Warsaw, Poland b World Hearing Center, ul. Mokra 17, Kajetany, 05-830 Nadarzyn, Poland c Heart Failure and Cardiac Rehabilitation Department of the Medical University of Warsaw, Warsaw, Poland d Institute of Sensory Organs, ul. Mokra 1, Kajetany, 05-830 Nadarzyn, Poland 1. Introduction Otoacoustic emissions (OAEs) [1] are believed to be good predictors of hearing status, particularly in the 1–4 kHz range. Click evoked OAEs (CEOAEs) are good indicators of cochlear function at 1 kHz, whereas distortion product OAEs (DPOAEs) perform better at higher frequencies. Both CEOAEs and DPOAEs perform poorly at 0.5 kHz [2–4] where there is still room for improvement. There is still some debate on the value of testing the hearing of schoolchildren. Newborn hearing screening has been universally applied in many countries but doing the same for schoolchildren is not widely practiced. Some organizations recommend screening of preschool and school-age children, pointing out the risks associated with undetected hearing loss [5]. There is also some controversy on what screening method is the best. Some studies recommend OAEs [6,7], while others suggest pure tone audiometry [8]. If OAEs could be evoked over a broader frequency range then it International Journal of Pediatric Otorhinolaryngology xxx (2015) xxx–xxx A R T I C L E I N F O Article history: Received 12 April 2015 Received in revised form 29 May 2015 Accepted 31 May 2015 Available online xxx Keywords: Tone burst evoked otoacoustic emissions Click evoked otoacoustic emissions Spontaneous otoacoustic emissions Transiently evoked otoacoustic emissions OAE Schoolchildren A B S T R A C T Introduction: Otoacoustic emissions (OAEs) are believed to be good predictors of hearing status, particularly in the 1–4 kHz range. However both click evoked OAEs (CEOAEs) and distortion product OAEs (DPOAEs) perform poorly at 0.5 kHz. The present study investigates OAEs in the lower frequency range of 0.5–1 kHz evoked by 0.5 kHz 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, 0.5 kHz 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 1–4 kHz, with a substantial decrease below 1 kHz. Responses from the 0.5 kHz TBOAEs were complementary in that the main components occurred between 0.5 and 1.4 kHz. In younger children, TBOAEs had SNRs 4–8 dB smaller in the 0.5–1.4 kHz range. In addition, CEOAEs had lower SNRs in the 0.7–1.4 kHz range, by 3–5 dB. TBOAEs in younger children had maximum SNRs shifted toward 1–1.4 kHz, whereas in older children it was more clearly around 1 kHz. 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. Conclusion: TBOAEs evoked at 0.5 kHz can provide additional information about frequencies below 1 kHz, 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 0.5 kHz TBOAEs had higher SNRs at 0.5–1.4 kHz. Additionally, for ears with SOAEs, 0.5 kHz TBOAEs had higher response levels and SNRs similar to CEOAEs. ß 2015 Elsevier Ireland Ltd. All rights reserved. * Corresponding author at: World Hearing Center, ul. Mokra 17, Kajetany, 05-830 Nadarzyn, Poland. Tel.: +48 22 35 60 574; fax: +48 22 35 60 367. E-mail address: w.jedrzejczak@ifps.org.pl (W.W. Jedrzejczak). G Model PEDOT-7616; No. of Pages 6 Please cite this article in press as: W.W. Jedrzejczak, et al., Tone burst evoked otoacoustic emissions in different age-groups of schoolchildren, Int. J. Pediatr. Otorhinolaryngol. (2015), http://dx.doi.org/10.1016/j.ijporl.2015.05.040 Contents lists available at ScienceDirect International Journal of Pediatric Otorhinolaryngology jo ur n al ho m ep ag e: ww w.els evier .c om /lo cat e/ijp o r l http://dx.doi.org/10.1016/j.ijporl.2015.05.040 0165-5876/ß 2015 Elsevier Ireland Ltd. All rights reserved.