Quantitative Timed-Up-and-Go Parameters in Relation to Cognitive Parameters and Health-Related Quality of Life in Mild-to-Moderate Parkinson's Disease

Introduction:
The instrumented Timed Up and Go test (iTUG) provides detailed information on movement sub-phases including sit-to-walk, straight walking, turning, and walk-to-sit. This study examined the contribution of these sub-phases to clinically relevant deficits in Parkinson’s disease (PD). We investigated whether fast speed (FS) or convenient speed (CS) better differentiates mild- to moderate-stage PD patients from controls, which iTUG parameters differ between groups, and how these parameters relate to cognition—especially executive function—and health-related quality of life (HRQoL).

Methods:
Twenty-eight PD patients (65.1 ± 7.1 years; Hoehn & Yahr stages 1–3; medication OFF) and 20 age-matched controls performed the iTUG under CS and FS conditions using wearable sensors. HRQoL was assessed with the PDQ-39, and cognitive and executive functions were evaluated using the Montreal Cognitive Assessment and Trail Making Test.

Results:
Total iTUG duration and sub-phase durations under FS differentiated PD patients slightly better than CS. Prolonged sit-to-walk, turning, and walk-to-sit phases accounted for the increased total duration in PD. iTUG parameters showed no relevant association with general cognition. Turning duration and walk-to-sit maximum flexion velocity correlated most strongly with executive function, while walking-back duration correlated most strongly with HRQoL.

Discussion:
Mild- to moderate-stage PD patients require more time to complete the iTUG than controls. FS appears more sensitive than CS for detecting subtle motor deficits. Furthermore, specific iTUG sub-phases and kinematic parameters may serve as surrogate markers for movement automaticity and reflect executive function and HRQoL in PD.