title: Changes in brainstem auditory response threshold in preterm babies from birth to late term.
abstract: CONCLUSIONS
  The hearing threshold in preterm infants was 23 dB above adult hearing level at 30 weeks gestation, and decreased to around 13 dB at term date. There was no major difference in the threshold for infants born at different gestations. At term, 9% had hearing threshold elevation.
  
  
  OBJECTIVE
  To examine changes in hearing threshold from preterm to term in infants born at 30-36 weeks gestation and to detect the prevalence of threshold elevation.
  
  
  METHODS
  The threshold in brainstem auditory evoked response (BAER) was obtained 656 times from postconceptional age (PCA) 30 to 42 weeks in 268 infants born at 30-36 weeks gestation.
  
  
  RESULTS
  The BAER threshold was 23 dB nHL at the youngest age (PCA 30 weeks), and then decreased to around 13 dB nHL at later preterm and term dates (PCA 35-42 weeks). The threshold was decreased with increasing age at a rate of 1.24 dB per week from PCA 30 to 36 weeks and 0.65 dB per week from PCA 30 to 42 weeks. At PCA 33-42 weeks, there were no significant differences in BAER threshold between the infants born at gestational age (GA) 30-32 weeks and those at GA 33-36 weeks. At term, 9% had threshold elevation (>20 dB nHL).
authors.affiliation: Division of Neonatology, Children's Hospital, Fudan University, Shanghai, China.
authors.forename: Li L
authors.initials: LL
authors.lastname: Ping
authors.forename: Ze D
authors.initials: ZD
authors.lastname: Jiang
mesh_terms: D000367:Age Factors; D001309:Auditory Threshold; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology* / Q000523:psychology; D008297:Male; D012016:Reference Values