title: Scotopic spatiotemporal sensitivity differences between young and old adults.
abstract: BACKGROUND
  Our lab has previously demonstrated losses in contrast sensitivity to low spatial frequencies under scotopic conditions with older adults. It is not clear, however, whether the temporal frequency of a stimulus alters the relation between age and the spatial contrast sensitivity function (sCSF) under scotopic conditions.
  
  
  METHODS
  A maximum-likelihood, two-alternative, temporal forced-choice QUEST procedure was used to measure threshold to spatially and temporally modulated stimuli in both young (mean = 26 years) and old (mean = 75 years) adults.
  
  
  RESULTS
  In general, the shapes of the spatial and temporal CSFs were low-pass for both young and old observers; contrast sensitivity decreased at approximately the same rate with increasing spatial frequency and temporal frequency for both age groups, although the overall sensitivity of the old group was lower than that of the young group. The high-frequency resolution limit was lower for the old group compared to the young group.
  
  
  CONCLUSIONS
  The differences in contrast sensitivity between the young and old groups suggest a uniform loss in sensitivity of the channels mediating spatial and temporal vision. Because of this loss, the spatial and temporal window of visibility for the older adults is compromised relative to the younger adults.
authors.affiliation: School of Psychological Sciences, University of Northern Colorado, Campus Box 94, Greeley, CO, USA.
authors.forename: Cynthia L
authors.initials: CL
authors.lastname: Clark
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Hardy
authors.forename: Vicki J
authors.initials: VJ
authors.lastname: Volbrecht
authors.forename: John S
authors.initials: JS
authors.lastname: Werner
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D055254:Night Vision / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D012684:Sensory Thresholds / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult