title: Continued maturation of the click-evoked auditory brainstem response in preschoolers.
abstract: BACKGROUND
  Click-evoked auditory brainstem responses (ABRs) are a valuable tool for probing auditory system function and development. Although it has long been thought that the human auditory brainstem is fully mature by age 2 yr, recent evidence indicates a prolonged developmental trajectory.
  
  
  OBJECTIVE
  The purpose of this study was to determine the time course of ABR maturation in a preschool population and fill a gap in the knowledge of development.
  
  
  METHODS
  Using a cross-sectional design, we investigated the effect of age on absolute latencies, interwave latencies, and amplitudes (waves I, III, V) of the click-evoked ABR.
  
  
  METHODS
  A total of 71 preschoolers (ages 3.12-4.99 yr) participated in the study. All had normal peripheral auditory function and IQ.
  
  
  METHODS
  ABRs to a rarefaction click stimulus presented at 31/sec and 80 dB SPL (73 dB nHL) were recorded monaurally using clinically-standard recording and filtering procedures while the participant sat watching a movie. Absolute latencies, interwave latencies, and amplitudes were then correlated to age.
  
  
  RESULTS
  Developmental changes were restricted to absolute latencies. Wave V latency decreased significantly with age, whereas wave I and III latencies remained stable, even in this restricted age range.
  
  
  CONCLUSIONS
  The ABR does not remain static after age 2 yr, as seen by a systematic decrease in wave V latency between ages 3 and 5 yr. This finding suggests that the human brainstem has a continued developmental time course during the preschool years. Latency changes in the age 3-5 yr range should be considered when using ABRs as a metric of hearing health.
authors.affiliation: Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL.
authors.forename: Emily
authors.initials: E
authors.lastname: Spitzer
authors.affiliation: Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL.
authors.forename: Travis
authors.initials: T
authors.lastname: White-Schwoch
authors.affiliation: Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL.
authors.forename: Kali Woodruff
authors.initials: KW
authors.lastname: Carr
authors.affiliation: Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL; Current address: Department of Speech, Language, and Hearing Sciences, Department of Psychology Affiliate, Cognitive Science Program Affiliate, University of Connecticut, Storrs, CT.
authors.forename: Erika
authors.initials: E
authors.lastname: Skoe
authors.affiliation: Department of Communication Sciences, Auditory Neuroscience Laboratory, www.brainvolts.northwestern.edu, Northwestern University, Evanston, IL; Department of Neurobiology and Physiology, Department of Otolaryngology, Institute for Neuroscience, Northwestern University, Evanston, IL.
authors.forename: Nina
authors.initials: N
authors.lastname: Kraus
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D001309:Auditory Threshold / Q000502:physiology*; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006320:Hearing Tests; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology