ITUG, a sensitive and reliable measure of mobility

Arash Salarian, Fay B. Horak, Cris Zampieri, Patricia Carlson-Kuhta, John G. Nutt, Kamiar Aminian

Research output: Contribution to journalArticlepeer-review

350 Scopus citations


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° 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° /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 testretest 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.

Original languageEnglish (US)
Article number5446357
Pages (from-to)303-310
Number of pages8
JournalIEEE Transactions on Neural Systems and Rehabilitation Engineering
Issue number3
StatePublished - Jun 2010


  • Balance
  • Gait
  • Mobility
  • Objective assessment
  • Wearable sensors

ASJC Scopus subject areas

  • Internal Medicine
  • Neuroscience(all)
  • Biomedical Engineering


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