James B Tracy1, Drew A Petersen2, Benjamin C Conner3, Justus G Matteson1, De'Shjuan G Triplett1, Henry G Wright1, Christopher M Modlesky4, Freeman Miller5, Curtis L Johnson6, Jeremy R Crenshaw7. 1. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA. 2. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA; Department of Physical Therapy, Drexel University, Philadelphia, PA, USA. 3. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA; College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA. 4. Department of Kinesiology, University of Georgia, Athens, GA, USA. 5. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA; Department of Orthopedics, Nemours A.I. duPont Hospital for Children, Wilmington, DE, USA. 6. Department of Biomedical Engineering, University of Delaware, Newark, DE, USA. 7. Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA. Electronic address: crenshaw@udel.edu.
Abstract
BACKGROUND: Standing postural sway is often quantified from center of pressure trajectories. During assessments of longer durations, children may fidget, thus limiting the feasibility and validity of sway recordings. RESEARCH QUESTION: Do postural sway sample durations less than 30 s maintain construct and concurrent validity? METHODS: In this case-control, observational study, we measured postural sway in 41 children (age 5-12 years, 23 typically developing (TD); 18 with spastic cerebral palsy (CP), 13 diplegic and 5 hemiplegic, 11 GMFCS level I and 7 level II) for 30-second eyes-opened and eyes-closed conditions. From a single recording, 5-second incremental durations of 5-30 s were considered in this analysis. We quantified anteroposterior, mediolateral, and transverse-plane sway using seven time-domain variables: root-mean-square error, total excursion, mean frequency, mean distance, sway area, and 95 % confidence circle and ellipse areas. Variables were calculated in eyes-opened and eyes-closed conditions, as well as the ratio of the two. Construct validity was evaluated by the persistence of large effect sizes (Glass's Δ ≥ 0.80) between CP and TD participants at shorter durations than 30 s. Concurrent validity was evaluated by the correlations of shorter duration measures to the 30 s measure. RESULTS: Seven sway measures had large between-group effects (Glass's Δ ≥ 1.02) for the 30 s measure that persisted (Glass's Δ ≥ 0.81) at shorter durations (5-25 s) and also maintained concurrent validity (r ≥ 0.83). Six of these seven measures were taken in the eyes-closed condition, and all seven measures were in the mediolateral direction or transverse plane. SIGNIFICANCE: Our analysis suggests that sway durations less than 30 s can uphold construct and concurrent validity. These measures were primarily in the eyes-closed conditions and mediolateral direction. These results are a promising indicator that shorter-duration sway measures may be of utility when fidgeting prevents longer recordings.
BACKGROUND: Standing postural sway is often quantified from center of pressure trajectories. During assessments of longer durations, children may fidget, thus limiting the feasibility and validity of sway recordings. RESEARCH QUESTION: Do postural sway sample durations less than 30 s maintain construct and concurrent validity? METHODS: In this case-control, observational study, we measured postural sway in 41 children (age 5-12 years, 23 typically developing (TD); 18 with spastic cerebral palsy (CP), 13 diplegic and 5 hemiplegic, 11 GMFCS level I and 7 level II) for 30-second eyes-opened and eyes-closed conditions. From a single recording, 5-second incremental durations of 5-30 s were considered in this analysis. We quantified anteroposterior, mediolateral, and transverse-plane sway using seven time-domain variables: root-mean-square error, total excursion, mean frequency, mean distance, sway area, and 95 % confidence circle and ellipse areas. Variables were calculated in eyes-opened and eyes-closed conditions, as well as the ratio of the two. Construct validity was evaluated by the persistence of large effect sizes (Glass's Δ ≥ 0.80) between CP and TD participants at shorter durations than 30 s. Concurrent validity was evaluated by the correlations of shorter duration measures to the 30 s measure. RESULTS: Seven sway measures had large between-group effects (Glass's Δ ≥ 1.02) for the 30 s measure that persisted (Glass's Δ ≥ 0.81) at shorter durations (5-25 s) and also maintained concurrent validity (r ≥ 0.83). Six of these seven measures were taken in the eyes-closed condition, and all seven measures were in the mediolateral direction or transverse plane. SIGNIFICANCE: Our analysis suggests that sway durations less than 30 s can uphold construct and concurrent validity. These measures were primarily in the eyes-closed conditions and mediolateral direction. These results are a promising indicator that shorter-duration sway measures may be of utility when fidgeting prevents longer recordings.
Authors: Jeremy R Crenshaw; Drew A Petersen; Benjamin C Conner; James B Tracy; Jamie Pigman; Henry G Wright; Freeman Miller; Curtis L Johnson; Christopher M Modlesky Journal: Dev Med Child Neurol Date: 2020-03-02 Impact factor: 5.449
Authors: John F Stins; Annick Ledebt; Claudia Emck; Elisabeth H van Dokkum; Peter J Beek Journal: Behav Brain Funct Date: 2009-10-02 Impact factor: 3.759