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NCT Number: NCT07327346

GYKO-Based L-Test Reliability in Parkinson's Disease

This study aims to investigate the interrater and test-retest reliability of GYKO-based postural sway measurements collected during the L-Test and Timed Up and Go (TUG) test in individuals with Parkinson's disease (Hoehn & Yahr stages 1-3). Two independent raters will perform GYKO-based assessments of the L-Test and TUG with a 20-minute interval. Participants will return one week later to repeat the same procedures for test-retest reliability. Concurrent validity will be examined using the Berg Balance Scale.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Parkinson Disease Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Movement Disorders Nervous System Diseases Neurodegenerative Diseases Parkinsonian Disorders Synucleinopathies

Age range

50 year–85 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hasan Kalyoncu University

Gaziantep, Şahinbey, 27000, Turkey (Türkiye)

About this study

This study aims to investigate the test-retest and interrater reliability, as well as the concurrent validity, of GYKO-based postural sway measurements obtained during the L-Test and the Timed Up and Go (TUG) test in individuals with Parkinson's disease. Participants diagnosed with idiopathic Parkinson's disease (Hoehn & Yahr stages 1-3) will be evaluated using the GYKO inertial measurement unit, which provides quantitative postural sway parameters including ellipse area, mean length, mediolateral and anteroposterior mean length, mediolateral and anteroposterior mean distance, and velocity.

Two independent raters will perform GYKO-based assessments of the L-Test and TUG on the same day, with a 20-minute interval between raters, to determine interrater reliability. Participants will return one week later to repeat the same procedures, allowing assessment of test-retest reliability.

To examine concurrent validity, participants' functional balance will also be assessed using the Berg Balance Scale, and correlations between GYKO variables and clinical mobility tests (L-Test and TUG) will be analyzed.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of idiopathic Parkinson's disease
  • Hoehn & Yahr stage 1-3
  • Ability to walk independently with or without an assistive device
  • Ability to follow verbal instructions
  • Age 50-85

Exclusion criteria

  • Other neurological, vestibular, or musculoskeletal disorders affecting balance
  • Deep brain stimulation (DBS) implant
  • Severe visual or auditory impairment

Treatment and study plan

GYKO-Based Postural Sway Assessment

Other

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.

Primary outcomes

  1. Interrater Reliability of GYKO-Based Postural Sway Parameters

    Time frame: Day 1

    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.

  2. Test-Retest Reliability of GYKO-Based Postural Sway Parameters

    Time frame: 1 week

    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.

Secondary outcomes

  1. Validity of GYKO Postural Sway Parameters with Functional Mobility (TUG and L-Test)

    Time frame: Day 1

    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.

  2. Relationship Between Postural Sway and Balance Performance (Berg Balance Scale)

    Time frame: Day 1

    Balance performance will be assessed using the Berg Balance Scale at baseline. The relationship between Berg Balance Scale scores and the composite GYKO-based postural sway parameters obtained during the Timed Up and Go (TUG) and L-Test procedures will be analyzed using Pearson correlation coefficients.

  3. L test and TUG Completion Time

    Time frame: 1 week

    Functional mobility will be assessed using the Timed Up and Go (TUG) test and the L-Test. The TUG requires participants to stand up from a chair, walk 3 meters, turn, return, and sit down.

    The L-Test is a modified version of the TUG and consists of standing up from a chair, walking 3 meters, performing a 90° turn, walking an additional 7 meters, performing a 180° turn, and returning along the same path (total walking distance approximately 20 meters).

    The time required to complete each test will be recorded in seconds.

Sponsors and collaborators

Lead sponsor

Hasan Kalyoncu University

Other

Registry information

Official study title

Test-Retest and Interrater Reliability and Validity of Postural Sway Parameters Measured With GYKO During the L Test in Individuals With Parkinson's Disease

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Jan 8, 2026
Registry last updated
Jan 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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