title: Association between saccular function and gait speed: data from the Baltimore Longitudinal Study of Aging.
abstract: OBJECTIVE
  To investigate whether otolith function (saccular and utricular) is associated with walking performance.
  
  
  METHODS
  Cross-sectional analysis of observational data collected in the Baltimore Longitudinal Study of Aging.
  
  
  METHODS
  National Institute on Aging Intramural Research Program Clinical Research Unit at Harbor Hospital, Baltimore, Maryland.
  
  
  METHODS
  Community-dwelling participants.
  
  
  METHODS
  Cervical and ocular vestibular evoked myogenic potentials (VEMPs) were used to assess saccular and utricular function, respectively.
  
  
  METHODS
  Cervical and ocular VEMP latency and amplitude responses and usual, rapid, and narrow (20 cm) gait speed assessed over a 6-m course.
  
  
  RESULTS
  In 314 participants (mean age, 73.1 yr; range, 26-96 yr), cervical VEMP amplitude mediated the association between age and gait speed-particularly narrow walk speed-in both men and women. Cervical VEMP latency had an independent association with gait speed in age-, height-, and weight-adjusted analyses, although the direction of the association differed by sex. Greater cervical VEMP latency was associated with slower usual, rapid, and narrow gait speed in women but faster rapid gait speed in men. Neither the amplitude nor latency of ocular VEMP was associated with gait speed in men or women.
  
  
  CONCLUSIONS
  These findings suggest that age-related slowing of gait speed is in part mediated by the decreased magnitude of saccular response associated with age. The sex-related differential association between saccular response latency and gait speed requires further study.
authors.affiliation: *Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, Baltimore; and the †National Institute on Aging, Longitudinal Studies Section, Harbor Hospital, Baltimore, Maryland, U.S.A.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Layman
authors.forename: Carol
authors.initials: C
authors.lastname: Li
authors.forename: Eleanor
authors.initials: E
authors.lastname: Simonsick
authors.forename: Luigi
authors.initials: L
authors.lastname: Ferrucci
authors.forename: John P
authors.initials: JP
authors.lastname: Carey
authors.forename: Yuri
authors.initials: Y
authors.lastname: Agrawal
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D015142:Baltimore; D001835:Body Weight / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012444:Saccule and Utricle / Q000502:physiology*; D058585:Vestibular Evoked Myogenic Potentials / Q000502:physiology*; D016138:Walking / Q000502:physiology