title: Quantitative analysis of gains and catch-up saccades of video-head-impulse testing by age in normal subjects.
abstract: OBJECTIVE
  To evaluate video-head-impulse test (vHIT) results in normal subjects, to determine the normative values of vHIT for the vestibulo-ocular reflex (VOR) and to characterise the catch-up saccades (CSs).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Tertiary care academic referral centre.
  
  
  METHODS
  Fifty healthy subjects with no history of vestibular impairment, ten each in their 20's, 30's, 40's, 50's and 60's, underwent vHITs in the lateral semicircular canal plane.
  
  
  METHODS
  vHIT gains and the incidence and amplitudes of covert and overt CSs.
  
  
  RESULTS
  The mean vHIT gain was 1.02 ± 0.07, and the mean gain asymmetry was 2.39 ± 1.96%, with no significant differences among age groups. CSs were observed during 22.6% of the trials and in 49% of the ears. The incidence of CSs was not associated with age. The mean velocity of CSs was 55.5 ± 16.9°/s, and its mean interaural difference was 11.8 ± 10.7°/s.
  
  
  CONCLUSIONS
  vHIT gains were consistently equal to 1.0 in all age groups (20's to 60's), suggesting that abnormal criteria for vHIT gain (e.g. 0.8) and gain asymmetry (e.g. 8%) can be used, regardless of age. CSs were observed in about half of normal ears, suggesting that VOR is a hypometric system. The amplitudes and interaural difference of CSs were also similar in all age groups, suggesting that abnormal criteria for CS amplitude (e.g. 100°/s) and interaural difference (e.g. 40°/s) can be used, regardless of age.
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: C J
authors.initials: CJ
authors.lastname: Yang
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: B C
authors.initials: BC
authors.lastname: Kang
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: H S
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Otorhinolaryngology-Head & Neck Surgery, Korea University Ansan Hospital, Ansan, Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Yoo
authors.affiliation: Department of Otolaryngology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. dzness@amc.seoul.kr.
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D064087:Head Impulse Test; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D014741:Video Recording