title: Interside Latency Differences in Brainstem Auditory and Somatosensory Evoked Potentials. Defining Upper Limits to Determine Asymmetry.
abstract: OBJECTIVE
  Limits of the interside differences are invaluable when interpreting asymmetry in brainstem auditory evoked potentials and somatosensory evoked potentials (SEP) recordings. The aim of this study was to analyze the normal upper limits of interside latency differences of brainstem auditory evoked potentials and SEP from the posterior tibial nerve and median nerve to determine asymmetry.
  
  
  METHODS
  The authors performed a prospective study in 56 healthy subjects aged 15 to 64 years with no neurological or hearing disorders. They analyzed (1) the latencies of I, III, and V waves and I-III, III-V, and I-V intervals and the amplitude ratios V/I and IV/I for brainstem auditory evoked potentials bilaterally; (2) the latencies of N8, N22, N28, and P37 waves and the interval N22-P37 and the amplitude P37 for posterior tibial nerve SEP bilaterally; and (3) the latencies and amplitudes of N9, N13, and N20 waves and N9-N13 and N13-N20 intervals for median nerve SEP bilaterally. The interside differences for these parameters were calculated and analyzed.
  
  
  RESULTS
  The authors obtained an upper limit for the interside latency differences from brainstem auditory evoked potentials that was significantly lower than the previously published data. However, the upper limits of interside latency differences for SEP were similar to those previously reported.
  
  
  CONCLUSIONS
  The findings of this study should be considered when laboratories analyze asymmetry using the normative data published by another center, however temporarily, in organizing new laboratories.
authors.affiliation: *Clinical Neurophysiology Department, ‡Neurosurgical Department, and †Neurosurgical and Neurotrauma Research Unit, Vall d'Hebron University Hospital, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Dulce
authors.initials: D
authors.lastname: Moncho
authors.forename: Maria A
authors.initials: MA
authors.lastname: Poca
authors.forename: Teresa
authors.initials: T
authors.lastname: Minoves
authors.forename: Alejandro
authors.initials: A
authors.lastname: Ferré
authors.forename: Juan
authors.initials: J
authors.lastname: Sahuquillo
mesh_terms: D000293:Adolescent; D000328:Adult; D004594:Electrophysiology / Q000592:standards*; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D055815:Young Adult