title: The effect of spectral filters on VEP and alpha-wave responses.
abstract: OBJECTIVE
  Spectral filters are used to treat light sensitivity in individuals with traumatic brain injury (TBI); however, the effect of these filters on normal visual function has not been elucidated. Thus, the current study aimed to determine the effect of spectral filters on objectively-measured visual-evoked potential (VEP) and alpha-wave responses in the visually-normal population.
  
  
  METHODS
  The full-field (15°H×17°V), pattern-reversal VEP (20' check size, mean luminance 52cd/m(2)) was administered to 20 visually-normal individuals. They were tested with four Intuitive-Colorimeter-derived, broad-band, spectral filters (i.e., gray/neutral density, blue, yellow, and red), which produced similar luminance values for the test stimulus. The VEP N75 and P100 latencies, and VEP amplitude, were recorded. Power spectrum analysis was used to derive the respective powers at each frequency, and peak frequency, for the selected 9-11Hz components of the alpha band.
  
  
  RESULTS
  Both N75 and P100 latencies increased with the addition of each filter when compared to baseline. Additionally, each filter numerically reduced intra-session amplitude variability relative to baseline. There were no significant effects on either the mean VEP amplitude or alpha wave parameters.
  
  
  CONCLUSIONS
  The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75%) to luminance, and in some cases, specific spectral effects (e.g., blue and red). VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared.
authors: Department of Biological and Vision Sciences, SUNY State College of Optometry, 33 West 42nd Street, New York, NY 10036, United States. Electronic address: kwilleford@sunyopt.edu.
authors: Kevin T
authors: KT
authors: Willeford
authors: Department of Biological and Vision Sciences, SUNY State College of Optometry, 33 West 42nd Street, New York, NY 10036, United States.
authors: Vanessa
authors: V
authors: Fimreite
authors: Department of Biological and Vision Sciences, SUNY State College of Optometry, 33 West 42nd Street, New York, NY 10036, United States.
authors: Kenneth J
authors: KJ
authors: Ciuffreda
mesh_terms: D000328:Adult; D004594:Electrophysiology; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D020795:Photophobia / Q000534:rehabilitation; D055139:Sensory Gating / Q000502:physiology*; D014792:Visual Acuity; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Brain injury; Color; Colored filters; Colorímetro Intuitivo; Corteza visual; Electrofisiología; Electrophysiology; Filtro espectral; Filtros coloreados; Intuitive Colorimeter; Lesión cerebral; Potencial evocado visual (PEV); Visual-evoked potential (VEP)