title: Dynamic pupillometry as an autonomic testing tool.
abstract: OBJECTIVE
  To determine normal values for pupillometry indices in healthy control subjects and to examine these indices in patients with autonomic dysfunction and healthy controls.
  
  
  METHODS
  Infrared video pupillometry was used to investigate the pupil response to a brief light flash in 79 healthy controls, 28 patients with normal autonomic function (composite autonomic severity score, CASS < 2), and 26 patients with moderate to severe autonomic failure (CASS > 4) seen in our autonomic laboratory from January 2008 to June 2011. In six subjects, we examined the effects of varying light stimulus intensity and light stimulus duration. Descriptive analysis, correlation, and ANCOVA adjusted for age were performed.
  
  
  RESULTS
  We determined eight indices corresponding to parasympathetic and sympathetic pupil function. Baseline pupil diameter (BPD), maximum constriction velocity (MCV), absolute constriction amplitude (ACA), and maximum dilation velocity (MDV) negatively correlated with age (p < 0.01) among controls. MCV and ACA increased with increasing intensity of light stimulus from 3.5 to 112 μW. Indices of parasympathetic pupil innervation (MCV and ACA) were lower in the high CASS group compared to others (p < 0.0001). Indices of sympathetic pupil function, time to reach 75 % of initial resting diameter during pupillary dilation (T¾), and dilation velocity at T¾ (DV¾) did not differ significantly in the three study groups. However, T¾ corrected for the magnitude of pupillary constriction (T¾:ACA) was higher in the high CASS group suggesting sympathetic dysfunction in that group (p = 0.0003).
  
  
  CONCLUSIONS
  Indices of pupillomotor function significantly differ between patients with moderate to severe autonomic failure and healthy controls.
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, 5323 Harry Hives Blvd, Dallas, TX, 75390-9129, USA, srikanth.muppidi@utsouthwestern.edu.
authors.forename: Srikanth
authors.initials: S
authors.lastname: Muppidi
authors.forename: Beverley
authors.initials: B
authors.lastname: Adams-Huet
authors.forename: Emil
authors.initials: E
authors.lastname: Tajzoy
authors.forename: Maggie
authors.initials: M
authors.lastname: Scribner
authors.forename: Paul
authors.initials: P
authors.lastname: Blazek
authors.forename: Elaine B
authors.initials: EB
authors.lastname: Spaeth
authors.forename: Elliott
authors.initials: E
authors.lastname: Frohman
authors.forename: Scott
authors.initials: S
authors.lastname: Davis
authors.forename: Steven
authors.initials: S
authors.lastname: Vernino
mesh_terms: D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D009460:Neurologic Examination / Q000379:methods*; D012025:Reflex, Pupillary / Q000502:physiology*; D055815:Young Adult