title: Maturation of the auditory system in clinically normal puppies as reflected by the brain stem auditory-evoked potential wave V latency-intensity curve and rarefaction-condensation differential potentials.
abstract: OBJECTIVE
  To evaluate auditory maturation in puppies.
  
  
  METHODS
  Ten clinically normal Beagle puppies.
  
  
  METHODS
  Puppies were examined repeatedly from days 11 to 36 after birth (8 measurements). Click-evoked brain stem auditory-evoked potentials (BAEP) were obtained in response to rarefaction and condensation click stimuli from 90 dB normal hearing level to wave V threshold, using steps of 10 dB. Responses were added, providing an equivalent to alternate polarity clicks, and subtracted, providing the rarefaction-condensation differential potential (RCDP). Steps of 5 dB were used to determine thresholds of RCDP and wave V. Slope of the low-intensity segment of the wave V latency-intensity curve was calculated. The intensity range at which RCDP could not be recorded (ie, pre-RCDP range) was calculated by subtracting the threshold of wave V from threshold of RCDP RESULTS: Slope of the wave V latency-intensity curve low-intensity segment evolved with age, changing from (mean +/- SD) -90.8 +/- 41.6 to -27.8 +/- 4.1 micros/dB. Similar results were obtained from days 23 through 36. The pre-RCDP range diminished as puppies became older, decreasing from 40.0 +/- 7.5 to 20.5 +/- 6.4 dB.
  
  
  CONCLUSIONS
  Changes in slope of the latency-intensity curve with age suggest enlargement of the audible range of frequencies toward high frequencies up to the third week after birth. Decrease in the pre-RCDP range may indicate an increase of the audible range of frequencies toward low frequencies. Age-related reference values will assist clinicians in detecting hearing loss in puppies.
authors: Department of Anatomy and Embryology, Faculty of Medicine, Free University of Brussels.
authors: L C
authors: LC
authors: Poncelet
authors: A G
authors: AG
authors: Coppens
authors: S I
authors: SI
authors: Meuris
authors: P F
authors: PF
authors: Deltenre
mesh_terms: D000818:Animals; D001306:Auditory Pathways / Q000254:growth & development*; D001933:Brain Stem / Q000502:physiology*; D004285:Dogs / Q000254:growth & development*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D008297:Male; D011930:Reaction Time; D012016:Reference Values