title: Pattern visual evoked potentials for identifying malingering.
abstract: OBJECTIVE
  To investigate the efficacy of pattern visual evoked potentials (VEPs) in evaluating objective visual acuity (VA) and discriminating malingerers.
  
  
  METHODS
  Two hundred and forty-nine eyes of 249 patients aged 20-65 years were included. There were 147 eyes with macular diseases (group 1) and 102 eyes with optic nerve diseases (group 2). Amplitudes and latencies were analyzed and correlated with best-corrected visual acuity by a regression analysis. We found the best-correlated mode of pattern VEP, determined the relations, and then calculated the pattern VEP-estimated VA (PVEP-VA) of all 249 eyes, another 30 malingering eyes, 13 eyes with macular diseases, and 17 eyes with optic nerve diseases, and used a receiver operating characteristic (ROC) curve to determine a cutoff for acceptable variance between PVEP-VA and subjective VA to discriminate malingerers.
  
  
  RESULTS
  The best correlation was between the amplitude of 50' checkerboard size (Amp50') and VA in every group. Significant correlation was between Amp50' and VA, where p < 0.0001 in group 1 and p = 0.020 in group 2. A logarithmic curve best fitted the correlation in the regression analysis, where y = 1.731 - 1.569x (R(2) = 0.611, p < 0.0001) in group 1 and y = 2.413 - 2.169x (R(2) = 0.531, p < 0.0001) in group 2 [x: log(Amp50'), y: PVEP-VA (logMAR)]. By using the relations and ROC curve, we determined a variance value of 0.4041 (logMAR) with 100% sensitivity and 94.0% specificity in group 1 and 0.3658 with 70.6% sensitivity and 50.5% specificity in group 2 to discriminate malingerers.
  
  
  CONCLUSIONS
  The pattern VEP amplitude of 50' checkerboard size was useful to assess VA and can be helpful in discriminating malingering from real disability.
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, 123 Dapi Road, Niao Sung District, Kaohsiung City, Taiwan.
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Sun
authors.forename: Jong-Jer
authors.initials: JJ
authors.lastname: Lee
authors.forename: Hsiu-Mei
authors.initials: HM
authors.lastname: Huang
authors.forename: Hsi-Kung
authors.initials: HK
authors.lastname: Kuo
mesh_terms: D000328:Adult; D000368:Aged; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D008306:Malingering / Q000175:diagnosis* / Q000503:physiopathology; D008875:Middle Aged; D009901:Optic Nerve Diseases; D012372:ROC Curve; D012164:Retinal Diseases; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology; D014794:Visual Fields / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology; D055815:Young Adult