title: Distortion-product otoacoustic emission growth curves in neonates.
abstract: BACKGROUND
  The recording of otoacoustic emissions (OAE) enabled us to prove that the cochlea is able not only to receive sounds but also to produce acoustic energy. Through the use of distortion-product otoacoustic emission measurements, the growth of the response was seen according to the intensity of the sound stimulus presented (growth curve).
  
  
  OBJECTIVE
  to determine the thresholds for the emergence of distortion-product otoacoustic emissions (DPOAE) on frequencies of 2000 and 4000 Hz with a stimulus varying from 20 to 65 dB SPL, and to establish the slope values obtained in the growth curves.
  
  
  METHODS
  39 neonates aged 5 to 28 days without risk indicators of hearing loss were studied. The DPOAE growth curves were obtained on the frequencies from 2000 Hz and 4000 Hz with a level of intensity ranging from 20 to 65 dB SPL divided into two paradigms (20 to 40 dB SPL and 40-65 dB SPL).
  
  
  RESULTS
  there was a statistically significant difference in the thresholds for the emergence of DPOAE depending on the criteria used. The thresholds were on average higher at 4000 Hz than 2000 Hz and the slope was higher on average at 2000 Hz than 4000 Hz, although not statistically significant in either case.
  
  
  CONCLUSIONS
  the thresholds were on average 30 dB SPL at 2000 Hz and 35 dB SPL at 4000 Hz. The slope values varied between 3 and 4 on average, reaching 15 in some cases.
authors: Faculty of Medical Sciences, Santa Casa de São Paulo, São Paulo, SP, Brazil.
authors: Tania Alves
authors: TA
authors: Barbosa
authors: Faculty of Medical Sciences, Santa Casa de São Paulo, São Paulo, SP, Brazil.
authors: Alessandra Spada
authors: AS
authors: Durante
authors: Department of Otorhinolaryngology, Faculty of Medical Sciences, Santa Casa de São Paulo, São Paulo, SP, Brazil.
authors: Lidio
authors: L
authors: Granato
mesh_terms: D000161:Acoustic Stimulation; D001309:Auditory Threshold / Q000502:physiology; D003051:Cochlea / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006320:Hearing Tests; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening / Q000379:methods; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011446:Prospective Studies; D012016:Reference Values; D047929:Term Birth / Q000502:physiology