title: iTUG, a sensitive and reliable measure of mobility.
abstract: Timed Up and Go (TUG) test is a widely used clinical paradigm to evaluate balance and mobility. Although TUG includes several complex subcomponents, namely: sit-to-stand, gait, 180 degree turn, and turn-to-sit; the only outcome is the total time to perform the task. We have proposed an instrumented TUG, called iTUG, using portable inertial sensors to improve TUG in several ways: automatic detection and separation of subcomponents, detailed analysis of each one of them and a higher sensitivity than TUG. Twelve subjects in early stages of Parkinson's disease (PD) and 12 age matched control subjects were enrolled. Stopwatch measurements did not show a significant difference between the two groups. The iTUG, however, showed a significant difference in cadence between early PD and control subjects (111.1 +/- 6.2 versus 120.4 +/- 7.6 step/min, p < 0.006) as well as in angular velocity of arm-swing (123 +/- 32.0 versus 174.0+/-50.4 degrees/s, p < 0.005), turning duration (2.18 +/- 0.43 versus 1.79 +/- 0.27 s, p < 0.023), and time to perform turn-to-sits (2.96 +/- 0.68 versus 2.40 +/- 0.33 s, p < 0.023). By repeating the tests for a second time, the test-retest reliability of iTUG was also evaluated. Among the subcomponents of iTUG, gait, turning, and turn-to-sit were the most reliable and sit-to-stand was the least reliable.
authors.affiliation: Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédéral de Lausanne, Lausanne, CH-1015 Lausanne, Switzerland. salarian@ieee.org
authors.forename: Arash
authors.initials: A
authors.lastname: Salarian
authors.forename: Fay B
authors.initials: FB
authors.lastname: Horak
authors.forename: Cris
authors.initials: C
authors.lastname: Zampieri
authors.forename: Patricia
authors.initials: P
authors.lastname: Carlson-Kuhta
authors.forename: John G
authors.initials: JG
authors.lastname: Nutt
authors.forename: Kamiar
authors.initials: K
authors.lastname: Aminian
mesh_terms: D001696:Biomechanical Phenomena; D003627:Data Interpretation, Statistical; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D010300:Parkinson Disease / Q000503:physiopathology; D004856:Postural Balance / Q000502:physiology*
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