title: Brainstem auditory evoked responses in foals: reference values, effect of age, rate of acoustic stimulation, and neurologic deficits.
abstract: BACKGROUND
  Age and rate of acoustic stimulation affect peak latencies in brainstem auditory evoked responses (BAER) in humans. Those effects are unknown in foals.
  
  
  OBJECTIVE
  Our goals were to (1) establish reference values for BAER in foals by using 3 different stimulation protocols, (2) evaluate the effects of age and stimulation frequencies on BAER tracing in foals up to 6 months old, and (3) compare the data with BAER obtained from foals with central nervous system (CNS) disorders.
  
  
  METHODS
  Thirty-nine neurologically normal foals and 16 foals with neurologic diseases.
  
  
  METHODS
  Prospective observational clinical study. BAER recorded by using 3 protocols of stimulation (11.33 repetitions per second [Hz]/70 decibel normal hearing level [dBNHL]; 11.33 Hz/90 dBNHL; 90 Hz/70 dBNHL).
  
  
  RESULTS
  No effect of age was observed in normal foals (P > .005). No significant difference was observed for latencies and interpeak latencies (IPL) when comparing foals with neurologic diseases and normal foals (P > .05), but 78.6% of foals with neurologic diseases had an asymmetry in their tracing, reflecting a difference in conduction time between the left and right side of the brainstem. Increasing the stimulation rate did not improve detection of CNS disorders.
  
  
  CONCLUSIONS
  We propose BAER reference values for foals up to 6 months of age by using 3 protocols. Most foals with neurologic deficits had abnormal BAER tracing.
authors.affiliation: Département de Sciences Cliniques, Université de Montréal, Saint-Hyacinthe, QC, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Lecoq
authors.forename: M
authors.initials: M
authors.lastname: Gains
authors.forename: L
authors.initials: L
authors.lastname: Blond
authors.forename: J
authors.initials: J
authors.lastname: Parent
mesh_terms: D000375:Aging; D000818:Animals; D002493:Central Nervous System Diseases / Q000175:diagnosis / Q000662:veterinary*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D006734:Horse Diseases / Q000175:diagnosis*; D006736:Horses; D012016:Reference Values
keywords: BAER; Brainstem auditory evoked potentials; Equine neonatology