title: Effect of binasal occlusion (BNO) and base-in prisms on the visual-evoked potential (VEP) in mild traumatic brain injury (mTBI).
abstract: OBJECTIVE
  To assess quantitatively the effect and relative contribution of binasal occlusion (BNO) and base-in prisms (BI) on visually-evoked potential (VEP) responsivity in persons with mild traumatic brain injury (mTBI) and the symptom of visual motion sensitivity (VMS), as well as in visually-normal (VN) individuals.
  
  
  METHODS
  Subjects were comprised of 20 VN adults and 15 adults with mTBI and VMS. There were four test conditions: (1) conventional pattern VEP, which served as the baseline comparison condition; (2) VEP with BNO alone; (3) VEP with 2 pd BI prisms before each eye; and (4) VEP with the above BNO and BI prism combination.
  
  
  RESULTS
  In mTBI, the mean VEP amplitude increased significantly in nearly all subjects (∼90%) with BNO alone. In contrast, in VN, it decreased significantly with BNO alone in all subjects (100%), as compared to the other test conditions. These objective findings were consistent with improvements in visual impressions and sensorimotor tasks in the group with mTBI. Latency remained within normal limits under all test conditions in both groups.
  
  
  CONCLUSIONS
  Only the BNO condition demonstrated significant, but opposite and consistent, directional effects on the VEP amplitude in both groups. The BNO-VEP test condition may be used clinically for the objectively-based, differential diagnosis of persons suspected of having mTBI and VMS from the VNs.
authors: Department of Biological and Vision Sciences, SUNY State College of Optometry , New York City, NY , USA.
authors: Naveen K
authors: NK
authors: Yadav
authors: Kenneth J
authors: KJ
authors: Ciuffreda
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001930:Brain Injuries / Q000150:complications / Q000503:physiopathology* / Q000534:rehabilitation; D005074:Evoked Potentials, Visual; D005139:Eyeglasses; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000503:physiopathology* / Q000534:rehabilitation; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013037:Spatial Behavior; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology* / Q000534:rehabilitation; D058609:Visual Field Tests; D014795:Visual Pathways / Q000293:injuries / Q000503:physiopathology*
keywords: Base-in prism; binasal occlusion (BNO); mild traumatic brain injury (mTBI); objective mTBI biomarker; visual motion sensitivity (VMS); visual-evoked potential amplitude; visual-evoked potential latency