ABSTRACT
BACKGROUND: Photo-based measurement methods are used to assess axial postural abnormalities (PA) in Parkinson's disease (PD). However, they capture only moments in time. We developed the 2-minute standing endurance test (2â¯M-SET), which specifically captures temporal changes in posture, as a novel dynamic method for measuring axial PA in patients with PD. RESEARCH QUESTION: This study aimed to verify the effectiveness and validity of the 2â¯M-SET for capturing temporal changes in axial PA in patients with PD. METHODS: Twenty-eight patients with PD participated. The participants attempted to maintain an upright posture for 2â¯minutes during three tasks: standing, stepping in place, and walking. The rate of change in postural angle was recorded at 10-second intervals. Based on the results, the 2â¯M-SET was developed. Therapists evaluated the 2â¯M-SET using the NeuroPostureApp© to measure anterior trunk flexion (ATF) angles and lateral trunk flexion (LTF) angles at 0, 10, 30, 60, and 120â¯seconds. To assess reliability, the congruence between the measurements obtained by the therapists and those obtained using a three-dimensional motion-analysis system was examined. For validity, we assessed whether the ATF and LTF angles measured by the therapists could accurately capture postural changes at regular intervals over time. RESULTS: The average postural changes over 2â¯minutes for the standing, stepping in place, and gait tasks were 59.2±83.5%, 37.6±30.7%, and 45.4±50.6%, respectively. The intraclass correlation coefficients showed high reliability, with values of 0.985 and 0.970 for the ATF and LTF angles, respectively. SIGNIFICANCE: The results of our proposed 2â¯M-SET method, which uses temporal photo-based measurements to assess the patient's ability to maintain an upright standing position for 2â¯minutes, demonstrate the potential to capture temporal changes in axial PA. DATA AVAILABILITY STATEMENT: The data supporting the findings of this study are available upon reasonable request and approval from the local ethics committee.