The instrumented timed up and go test: potential outcome measure for disease modifying therapies in Parkinson's disease

Abstract

The Timed Up and Go (TUG) test has been used to assess balance and mobility in Parkinson’s Disease (PD). However, it is not known if this test is sensitive to subtle abnormalities present in early stages of the disease, when balance and gait problems are not clinically evident but may be detected with instrumented analysis of movement. We hypothesize that postural transitions and arm swing during gait will be the most sensitive characteristics of the TUG for early PD. In the present study, we instrumented the TUG test (iTUG) using portable inertial sensors, and extended the walking distance from 3 meters (traditional TUG) to 7 meters. Twelve subjects with early-to-moderate, untreated PD and 12 healthy individuals participated. Our findings show that although the stopwatch measure of TUG duration did not detect abnormalities in early-to-mid stage PD, the peak arm swing velocity on the more affected side, average turning velocity, cadence and peak trunk rotation velocity were significantly slower. These iTUG parameters were also correlated with the UPDRS Motor Scale. Thus, the iTUG test is sensitive to untreated PD and could potentially detect progression of PD and response to symptomatic and disease-modifying treatments.

Reliability and validity of the inertial sensor-based Timed “Up and Go” test in individuals affected by stroke

“…Based on algorithms described elsewhere [18][19][28][29], different parameters of gait and postural transition during iTUG performance were measured.…”

“…A normalization of the arm swing on the affected side might be a parameter for recovery of normal gait. Zampieri et al identified the iTUG parameter "peak arm swing velocity" as one of the most sensitive deficits in early PD [19]. It might be that the parameter "arm swing" is also of clinical relevance poststroke.…”

“…However, although the TUG is commonly used to evaluate mobility poststroke, it has some drawbacks. First, it only uses the outcome parameter "time" and fails to detect other balance-and mobility-related parameters [18][19]. Second, although it consists of a number of consecutive tasks, it does not allow analysis of these tasks separately [18][19].…”

“…For example, Vernon et al used a Microsoft Kinect camera-based TUG method for analyzing the specific subcomponents of the test [20]. Furthermore, Zampieri et al revealed the potential benefit of an instrumented TUG (iTUG) system using wearable inertial sensors while assessing individuals with Parkinson disease (PD) [19]. While 10 of the 21 gait and postural transition parameters that were identifiable with the iTUG showed significant differences between individuals with PD and nondisabled controls, the total test performance time was not diverging.…”

Fall-Risk Classification of the Timed Up-And-Go Test with Principle Component Analysis

“…For fall-risk assessment, an instrumented TUG test that uses portable inertial sensors (iTUG test) has been proposed to improve the TUG test in several ways; namely, by allowing for automatic detection and separation of each performance, facilitating a detailed analysis of each and enabling a higher sensitivity than the TUG test [21,[24][25][26]. Sensitive and reliable measures for fall-risk assessment have been provided by measurement of wearable inertial sensors [27].…”