title: The development of an accelerometer-based measure of human upright static anterior- posterior postural sway under various sensory conditions: test-retest reliability, scoring and preliminary validity of the Balance Accelerometry Measure (BAM).
abstract: BACKGROUND
  Accelerometers are being used to assess postural control in adults, but there is little to support their reliability and validity.
  
  
  OBJECTIVE
  To estimate the test-retest reliability of the balance accelerometry measure (BAM) and to describe the known-groups validity of the BAM composite score.
  
  
  METHODS
  Two measures of standing postural sway were taken across six sensory (vision/stance surface) and motor stance (feet together or tandem) positions from eighteen patients with vestibular disorders and 84 healthy subjects. Test-retest reliability for postural sway was estimated across all conditions using intraclass correlation coefficient (ICC). A composite measure of sway standardized to young healthy subjects on eyes open firm surface stance was compared between groups.
  
  
  RESULTS
  Test-retest reliability of postural sway was good (ICC ⩾ 0.74) under all sensory conditions except eyes closed/tandem stance, which was slight to poor. Analysis of the receiver operating characteristic curve for composite scores indicated significant accuracy at identification of subjects in the vestibular/balance disorder groups. Composite standard scores equal or greater than 21.1 identified subjects with vestibular disorders with an accuracy of 72% sensitivity and 68% specificity.
  
  
  CONCLUSIONS
  The BAM displays good-excellent reliability for five of six sensory-motor conditions. The composite score appears to differentiate healthy from subjects with vestibular disorders.
authors.affiliation: Department of Physical Therapy, Duquesne University, Pittsburgh, PA, USA Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Marchetti
authors.forename: Jennica
authors.initials: J
authors.lastname: Bellanca
authors.forename: Susan L
authors.initials: SL
authors.lastname: Whitney
authors.forename: James Chia-Cheng
authors.initials: JC
authors.lastname: Lin
authors.forename: Mark C
authors.initials: MC
authors.lastname: Musolino
authors.forename: Gabriel R
authors.initials: GR
authors.lastname: Furman
authors.forename: Mark S
authors.initials: MS
authors.lastname: Redfern
mesh_terms: D061725:Accelerometry / Q000379:methods* / Q000706:statistics & numerical data; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology; D012372:ROC Curve; D015203:Reproducibility of Results; D015837:Vestibular Diseases / Q000175:diagnosis / Q000503:physiopathology; D055815:Young Adult
keywords: Balance; accelerometer; postural control