DOI: 10.5061/dryad.v6wwpzgsd
title: Data From: A new perspective on transient characteristics of quiet stance postural control

description: Postural control provides insight into health concerns such as fall risk
 but remains relatively untapped as a vital sign of health. One
 understudied aspect of postural control involves transient responses
 within center of pressure (CoP) data to events such as vision occlusion.
 Such responses are masked by common whole-trial analyses. We hypothesized
 that the transient behavior of postural control would yield unique and
 clinically-relevant information for quiet stance compared to traditionally
 calculated whole-trial CoP estimates. Three experiments were conducted to
 test different aspects of this central hypothesis. To test whether
 transient, epoch-based characteristics of CoP estimates provide different
 information than traditional whole-trial estimates, we investigated
 correlations between these estimates for a population of young adults
 performing three 60-second trials of quiet stance with eyes closed. Next,
 to test if transient behavior is a result of sensory reweighting after eye
 closure, we compared transient characteristics between eyes closed and
 eyes open conditions. Finally, to test if there was an effect of age on
 transient behavior, we compared transient characteristics during eyes
 closed stance between populations of young and older adults. Negligible
 correlations were found between transient characteristics and whole-trial
 estimates (p&gt;0.08), demonstrating limited overlap in information
 between them. Additionally, transient behavior was exaggerated during eyes
 closed stance relative to eyes open (p&lt;0.044). Lastly, we found
 that transient characteristics were able to distinguish between younger
 and older adults, supporting their clinical relevance (p&lt;0.029). An
 epoch-based approach captured unique and potentially clinically-relevant
 postural control information compared to whole-trial estimates. While
 longer trials may improve the reliability of whole-trial estimates,
 including a complementary assessment of the initial transient
 characteristics may provide a more comprehensive characterization of
 postural control.   
description: Description of methods used for collection/generation of
 data: Reed CA, AMW Chaudhari, LC Worthen-Chaudhari,
 Bigelow KE, Monfort SM (2020). A new perspective on transient
 characteristics of quiet stance postural control. PLOS ONE
 Instrument-specific information needed to interpret the
 data:<br> Vertical force and moments about the x and y axes were
 recorded at 1000 Hz using a balance plate (BP5046; Bertec Corp.; Columbus,
 OH) and captured using custom software written in LabView (National
 Instruments; Austin, TX). The LabVIEW program collected data from the
 balance plate using the Bertec Device SDK provided on Bertec's
 website at: http://www.bertec.com/downloads Standards
 and calibration information, if appropriate:<br> Before the 1st
 trial for every participant, the balance plate was zeroed.
 Methods for processing the data:<br> The data was processed
 in MATLAB using custom-scripts. Medio-lateral and Anterior-posterior CoP
 time series data was calculated using Bertec guidelines. CoP parameters
 were obtained based on calculations described by Prieto et al. (1996).
 Code may be available upon request. Participant
 Information:<br> Experiment 1-- 67 young adults (YA) (24.9 ± 3.9
 years, 75.7 ± 14.7 kg, 1.77 ± 0.09 m, 42 males/25 females)<br>
 Experiment 2-- a subseet of 30 young adults (YA) from Experiment 1 (22.9 ±
 2.6 years, 75.1 ± 11.6 kg, 1.77 ± 0.09 m, 18 males/12 females)<br>
 Experiment 3-- the 67 YA from Experiment 1 and 38 older adults (OA) (83.5
 ± 8.4 years, 66.5 ± 12.9 kg, 1.66 ± 0.09 m, 8 males/30 females)
 Inclusion/Exclusion Criteria:<br> YA = Individuals with a
 known neurological impairment, a prior lower-extremity joint replacement
 surgery, or a lower-extremity injury within the three months prior to
 testing were excluded.<br> OA = Individuals with any known
 neurological impairment or who could not stand for more than 5 minutes
 at a time without some form of assistance (e.g. cane, walker, etc.) were
 excluded. Environmental/experimental
 conditions:<br> Environmental--<br> The collections were
 performed in 3 different settings. The 2017 American Society of
 Biomechanics conference, the Montana State University Neuromuscular
 Biomechanics Lab, and various nursing home/assisted living facilities in
 Bozeman, MT. Experimental--<br> The data were
 collected in two different conditions: quiet, eyes closed (QEC) stance and
 quiet, eyes open (QEO) stance. Describe any
 quality-assurance procedures performed on the data:<br> All trials
 were quality controlled to ensure that they had approximately the same
 amount of data points. Certain trials were excluded due
 to a participant's failure to comply with test protocol, technical
 difficulties with data collection, or interruption of testing by outside
 noise or movement, etc. Within this dataset, the TrialNum (Trial Number)
 indicates the order that the trial was collected, accounting for both
 successful and excluded trials. This explains why certain participants may
 have a trial number above 1, 2, or 3, as some participants required more
 trials in order to obtain 3 successful trials.