Parkinson's disease patients with stage 1-3 hoehn yahr

This procedure involves obtaining postural sway parameters using the GYKO inertial measurement device during the Time Up and Go (TUG) test and L-Test. No therapeutic intervention is applied.

Time Up and Go Test: Timed Up and Go (TUG) is a standardized functional mobility test used to assess dynamic balance and gait performance. Participants are instructed to stand up from a standard-height chair, walk 3 meters, turn around, walk back to the chair, and sit down. The total time to complete the task (in seconds) is recorded. Higher times indicate reduced mobility.

L Test: Time (in seconds) to complete the L-Test of Functional Mobility. The test requires participants to stand up from a chair, walk 3 m, execute a 90° turn, walk another 7 m, perform a 180° turn, and return along the same path (total walking distance ≈ 20 m). The task ends when the participant sits back down. The total time to complete the task (in seconds) is recorded. Higher times indicate reduced mobility.

Interrater reliability of postural sway will be evaluated using a composite set of parameters derived from GYKO inertial sensor data collected during the Timed Up and Go (TUG) and L-Test procedures. Measurements will be obtained independently by two raters on the same day.

The composite postural sway outcome includes ellipsoid area, displacement-related parameters in the mediolateral and anteroposterior directions, and velocity-related parameters. Although individual variables are expressed in different units, all parameters collectively represent a single postural control construct.

Interrater reliability will be assessed using the intraclass correlation coefficient (ICC 2,1) with 95% confidence intervals.

Test-retest reliability of postural sway will be assessed using a composite set of parameters derived from GYKO inertial sensor data collected during the Timed Up and Go (TUG) and L-Test procedures. Participants will be re-evaluated after a 1-week interval.

The composite postural sway outcome includes ellipsoid area, mediolateral and anteroposterior displacement parameters, and velocity-related parameters, representing a single postural control construct.

Test-retest reliability will be analyzed using the intraclass correlation coefficient (ICC 3,1) with 95% confidence intervals. Paired t-tests will be used to examine differences between test and retest measurements.

Concurrent validity will be examined by analyzing the relationship between the composite GYKO-based postural sway parameters obtained during the Timed Up and Go (TUG) and L-Test procedures and functional mobility performance.

Pearson correlation coefficients will be used to assess the associations between postural sway composite outcomes and TUG and L-Test completion times.