title: Habituation measured by pattern reversal visual evoked potentials depends more on check size than reversal rate.
abstract: OBJECTIVE
  Results have varied between studies of pattern-reversal visual evoked potential (PR-VEP) habituation, possibly caused by differences in stimulation parameters. Our aim was to estimate the interaction between check size and reversal rate on PR-VEP-habituation in healthy subjects.
  
  
  METHODS
  Thirty-four healthy volunteers participated. Mid-occipital monocular PR-VEP was recorded in six consecutive blocks of 50 responses. Four conditions were applied in a random order: 1.5 reversals per second (rps) with 8' checks, 1.5 rps with 65' checks, 3.0 rps with 8' checks and 3.0 rps with 65' checks. N70-P100 and P100-N145 peak-to-peak amplitudes were blindly measured. ANOVA and regression slopes across the six blocks were used to test for habituation.
  
  
  RESULTS
  Significant habituation slopes were found with small 8' checks while responses were stable with large 65' checks for the fast reversal rate. We found a strong trend (p = 0.06) towards a significant interaction between reversal rate and check size on habituation for N70-P100.
  
  
  CONCLUSIONS
  Habituation may not be detectable in healthy subjects using large 65' checks. Reversal rate had less influence than check size on habituation. The faster 3.0 rps reversal rate will reduce examination time and probably prevent drowsiness.
  
  
  CONCLUSIONS
  Small checks and fast reversal rate may be preferable in PR-VEP habituation studies.
authors.affiliation: Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway. petterom@stud.ntnu.no
authors.forename: Petter M
authors.initials: PM
authors.lastname: Omland
authors.forename: Kristian B
authors.initials: KB
authors.lastname: Nilsen
authors.forename: Trond
authors.initials: T
authors.lastname: Sand
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology*; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult