title: The effect of aging on torsional optokinetic nystagmus.
abstract: OBJECTIVE
  The effect of aging on torsional optokinetic nystagmus (tOKN) is unknown. The authors investigated changes in tOKN associated with aging in a group of healthy subjects.
  
  
  METHODS
  Monocular torsional eye movements were recorded from 30 subjects between 19 and 72 years of age. Constant-velocity rotary stimuli in clockwise and counterclockwise directions were used to elicit tOKN at 40 degrees /s and 400 degrees /s.
  
  
  RESULTS
  The number of subjects in whom tOKN could not be detected increased with age and was consistent in both directions of stimulation and at both angular velocities of stimulation.
  
  
  CONCLUSIONS
  tOKN appears to fail increasingly with age, in contrast to previous reports of horizontal and vertical OKN systems. This indicates that the ability to respond to rotary motion is more sensitive to the effects of aging.
authors.affiliation: University of Leicester, Ophthalmology Group, Faculty of Medicine and Biological Sciences, Leicester, UK.
authors.forename: Shegufta J
authors.initials: SJ
authors.lastname: Farooq
authors.forename: Irene
authors.initials: I
authors.lastname: Gottlob
authors.forename: Sherwin
authors.initials: S
authors.lastname: Benskin
authors.forename: Frank A
authors.initials: FA
authors.lastname: Proudlock
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017120:Nystagmus, Optokinetic / Q000502:physiology*; D054159:Torsion, Mechanical