Objective: To create and test a smartphone application that enables self-administration of Timed-up-and-go (TUG) test, under both normal and dual-task conditions.

Background: The TUG test is a valid and reliable functional mobility measure in Parkinson’s disease (PD). The addition of a cognitive task to TUG (dual-task TUG) increases the sensitivity and specificity in predicting fall risks. Therefore, TUG and dual-task TUG are used commonly in clinical and research practice in PD. Such assessments, however, are limited primarily to clinic-based settings. Accurate regular self-monitoring can reduce unnecessary routine appointments, allow for timely intervention and might potentially lower healthcare cost.

Method: A smartphone application using the phone’s motion sensors to capture the time taken for TUG was created. With the phone strapped onto the wrist of the user, a timer was activated when the user pressed start on the smartphone and deactivated automatically once the user completed the TUG by sitting back down on the chair. For dual-task TUG, users were to count the frequency of even numbers being called out from a random presentation of numbers played from the application when performing TUG. 20 participations (10 healthy controls, 10 PwP) completed 3 separate trials of TUG and dual-task TUG, during which data were simultaneously collected via the application and manually using a stopwatch. Validity was evaluated by comparing the average time taken for TUG and dual-task TUG derived from the application and by stopwatch, using correlations and Bland-Altman plots.

Results: Both healthy participants (mean age, 52.3±9.4, 6 female) and PwP (mean age, 60.5 ± 9.1, 2 female, HY Stage ≤2) were able to self-administer the smartphone based TUG and dual-task TUG test. TUG performance derived from the application and stopwatch were highly correlated in both healthy individuals (P<0.001, r=0.90,) and PwP (P=0.002, r=0.85). Similarly, time taken to complete dual-task TUG obtained by the application also had a high correlation with stopwatch measurement in PwP (P<0.001, r=0.97). However, there is only a moderate correlation between dual-task TUG timings derived from the application and stopwatch in healthy individuals (P= 0.098, r= 0.552).

Conclusion: The smartphone-based application we created enabled valid assessments of TUG and dual-task TUG. Additional work is warranted to explore the feasibility of the application to be used in home settings.

References: 1. Vance RC, Healy DG, Galvin R, French HP. Dual tasking with the timed “up & go” test improves detection of risk of falls in people with Parkinson disease. Phys Ther 2005; 95: 95-102. 2. Dorsey ER, Sherer T, Okun MS, Bloem BR. The emerging evidence of the Parkinson pandemic. J Parkinsons Dis 2018; 8: S1-S8. doi:10.3233/jpd-181474

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MDS Abstracts - https://www.mdsabstracts.org/abstract/smartphone-based-mobility-assessment-in-parkinsons-disease-a-validity-study/