title: Can an accelerometer enhance the utility of the Timed Up & Go Test when evaluating patients with Parkinson's disease?
abstract: BACKGROUND
  The Timed Up and Go (TUG) test is a widely used measure of mobility and fall risk in older adults and in Parkinson's disease (PD). We tested the hypothesis that body-fixed accelerometers can provide insight into TUG performance in PD patients.
  
  
  METHODS
  We examined 17 patients with PD (Hoehn and Yahr score: 2.7+/-0.7; ON state) and 15 age-matched healthy controls; mean ages were 66.8+/-5.9 years, 67.6+/-9.6 years, respectively. Subjects wore a 3D-accelerometer (ADXL330, Analog Devices) on the lower back while performing the TUG test. Sit-to-Stand and Stand-to-Sit times were extracted from the anterior-posterior (AP) signal. Parameters included Sit-to-Stand, Stand-to-Sit durations, amplitude range (Range) and slopes (Jerk). Acceleration median and standard deviation (SD) were also calculated.
  
  
  RESULTS
  Stopwatch-based TUG duration tended to be higher for the PD patients compared to the control group, although not significantly (p=0.08). In contrast, the TUG duration that was extracted from the acceleration signal was significantly (p<0.02) higher in the PD group compared to the control group. Many acceleration-parameters were also significantly different (p<0.05) between groups; most were not correlated with TUG duration.
  
  
  CONCLUSIONS
  Accelerometer-derived parameters are sensitive to group differences, indicating that PD patients have poorer mobility during specific aspects of the TUG. In addition to test duration, these measures may serve as complementary and objective bio-markers of PD to augment the evaluation of disease progression and the response to therapeutic interventions.
authors: Laboratory for Gait & Neurodynamics, Movement Disorders Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
authors: Aner
authors: A
authors: Weiss
authors: Talia
authors: T
authors: Herman
authors: Meir
authors: M
authors: Plotnik
authors: Marina
authors: M
authors: Brozgol
authors: Inbal
authors: I
authors: Maidan
authors: Nir
authors: N
authors: Giladi
authors: Tanya
authors: T
authors: Gurevich
authors: Jeffrey M
authors: JM
authors: Hausdorff
mesh_terms: D000058:Accidental Falls; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000503:physiopathology*; D011187:Posture; D018570:Risk Assessment; D013997:Time Factors