title: Aging of vestibular function evaluated using correlational vestibular autorotation test.
abstract: BACKGROUND
  Imbalance from degeneration of vestibular end organs is a common problem in the elderly. However, the decline of vestibular function with aging was revealed in few vestibular function tests such as vestibular autorotation test (VAT). In the current VAT, there are drawbacks of poor test-retest reliability, slippage of the sensor at high-speed rotations, and limited data about the effect of aging. We developed a correlational-VAT (cVAT) system that included a small, light sensor (less than 20 g) with wireless data transmission technique to evaluate the aging of vestibular function.
  
  
  METHODS
  We enrolled 53 healthy participants aged between 25 and 75 years and divided them into five age groups. The test conditions were vertical and horizontal head autorotations of frequencies from 0 to 3 Hz with closed eyes or open eyes. The cross-correlation coefficient (CCC) between eye velocity and head velocity was obtained for the head autorotations between 1 Hz and 3 Hz. The mean of the CCCs was used to represent the vestibular function.
  
  
  RESULTS
  Age was significantly and negatively correlated with the mean CCC for all test conditions, including horizontal or vertical autorotations with open eyes or closed eyes (P<0.05). The mean CCC with open eyes declined significantly at 55-65 years old and the mean CCC with closed eyes declined significantly at 65-75 years old.
  
  
  CONCLUSIONS
  Vestibular function evaluated using mean CCC revealed a decline with age, and the function of visual-vestibulo-ocular reflex declined 10 years earlier than the function of vestibulo-ocular reflex.
authors.affiliation: Institute of Brain Science, School of Medicine, National Yang-Ming University, Taipei, Taiwan ; Department of Otolaryngology, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Li-Chun
authors.initials: LC
authors.lastname: Hsieh
authors.affiliation: Department of Otolaryngology, Mackay Memorial Hospital, Taipei, Taiwan ; Department of Audiology and Speech Language Pathology, Mackay Memorial Medical College, Taipei, Taiwan.
authors.forename: Hung-Ching
authors.initials: HC
authors.lastname: Lin
authors.affiliation: Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan ; Department of Otolaryngology, Taipei City Hospital, Ren-Ai Branch, Taipei, Taiwan.
authors.forename: Guo-She
authors.initials: GS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014724:Vestibular Function Tests / Q000379:methods*
keywords: aging; correlation analysis; electro-oculography; gyrometry; vestibular autorotation test