title: Balance performance in head-shake computerized dynamic posturography: aging effects and test-retest reliability.
abstract: BACKGROUND
  The ability of the Sensory Organization Test (SOT) to detect subtle balance problems has been challenged. The Head-Shake Sensory Organization Test (HS-SOT) has been developed to improve the delineation of balance performance.
  
  
  OBJECTIVE
  The purposes of this study were: (1) to examine age-related differences in balance measured with the HS-SOT and (2) to establish the test-retest reliability of the HS-SOT in younger adults who were healthy and older adults who were healthy.
  
  
  METHODS
  A test-retest design was used in this observational measurement study.
  
  
  METHODS
  Ninety-two younger adults who were healthy (mean age=28.3 years) and 73 older adults who were healthy (mean age=60.3 years) underwent the SOT and the HS-SOT. Seventy-seven of them (56 younger adults, 21 older adults) underwent the same assessments 1 to 2 weeks later.
  
  
  RESULTS
  The equilibrium scores in HS-SOT conditions 2 (head movements with eyes closed while standing on a firm surface) and 5 (head movements with eyes closed while standing on a sway-referenced surface) were significantly lower than those in tests without dynamic head movements added (SOT conditions 2 and 5). Older adults attained significantly lower scores in both HS-SOT conditions than their younger peers. The test-retest reliability values, reported as intraclass correlation coefficients (ICC [3,2]), of the HS-SOT scores in conditions 2 and 5 for the younger adults were .85 and .78, respectively; those for the older adults were .64 and .55, respectively. The corresponding minimal detectable change values for the former were 2.7 and 16.2, and those for the latter were 3.6 and 22.7.
  
  
  CONCLUSIONS
  Only head rotation movements on the horizontal plane were tested.
  
  
  CONCLUSIONS
  Adding head movements to the SOT increased the separation of younger adults who were healthy and older adults who were healthy. The HS-SOT has good reliability, and the reported minimal detectable change values may facilitate the interpretation of clinical studies in which the HS-SOT is used to assess changes in balance performance in younger and older adults.
authors.affiliation: Department of Rehabilitation Sciences, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Marco.Pang@inet.polyu.edu.hk
authors.forename: Marco Y C
authors.initials: MY
authors.lastname: Pang
authors.forename: Freddy M
authors.initials: FM
authors.lastname: Lam
authors.forename: Gary H
authors.initials: GH
authors.lastname: Wong
authors.forename: Ivy H
authors.initials: IH
authors.lastname: Au
authors.forename: Dorothy L
authors.initials: DL
authors.lastname: Chow
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D003936:Diagnosis, Computer-Assisted; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012678:Sensation Disorders / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult