<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03755336</url>
  </required_header>
  <id_info>
    <org_study_id>0877-18-EP</org_study_id>
    <nct_id>NCT03755336</nct_id>
  </id_info>
  <brief_title>Variability and Specificity in Reactive Stabilization Movements to Diverse Slip Perturbations</brief_title>
  <official_title>Variability and Specificity in Reactive Stabilization Movements to Diverse Slip Perturbations</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>University of Nebraska</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>University of Nebraska</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      To maintain mobility as we age we must navigate a complex environment that challenges us with&#xD;
      a range of disturbances.&#xD;
&#xD;
      Unfortunately, older adults are often unsuccessful in resisting these disturbances, and fall.&#xD;
      Falls are the greatest source of injury, and for older adults, the greatest source of&#xD;
      injury-related death. Approximately a quarter of falls happen following slips.&#xD;
&#xD;
      Recent research on slips has shown that use of perturbation training to improve specific&#xD;
      motor skills to resist slips can vastly reduce falls. However, these interventions have only&#xD;
      addressed slips occurring at heel-strike, and not the diverse range of slipping disturbances&#xD;
      presented by a complex environment. This project will focus on slips that occur across the&#xD;
      gait cycle, and the reactive stabilization movements that follow. Slips at different phases&#xD;
      of the gait cycle have unique biomechanical contexts, and successful reactive stabilization&#xD;
      movements are likely to be highly specific to that context. Yet nothing is known about the&#xD;
      specificity of the repertoire of reactive stabilization movements to resist different slip&#xD;
      conditions. Furthermore, variability in the repertoire of reactive stabilization movements is&#xD;
      likely to affect the success/failure rate of resisting these disturbances. Thus, the&#xD;
      objective of the proposed project is to determine the roles of variability and specificity in&#xD;
      reactive stabilization movements to resist falling in diverse slipping conditions. A novel&#xD;
      wearable apparatus for slip perturbations will deliver lifelike, unexpected slips in early,&#xD;
      middle and late stance in younger and older adults. Biomechanical analysis based on&#xD;
      three-dimensional motion capture data of the reactive stabilization movements will generate&#xD;
      novel results on the specificity and variability of protective stepping and arm swinging&#xD;
      responses. The central hypothesis is that increases in specificity and decreases in&#xD;
      variability of reactive stabilization movements will reduce fall rates. The first specific&#xD;
      aim is to quantify variability and specificity of reactive responses to diverse slip&#xD;
      perturbations and determine their relationships to fall rates. The second specific aim is to&#xD;
      determine how repeated exposure to diverse slip perturbations affects reactive responses, and&#xD;
      whether it relates to gait variability. The long-term objective of this research is to&#xD;
      support future studies into the repertoire of reactive stabilization movements across the&#xD;
      full range of disturbances faced in navigating the environment.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Subjects will be recruited through fliers from local exercise and community centers,&#xD;
      independent senior living centers, and on the campus of the University of Nebraska at Omaha.&#xD;
      Younger subjects age 19-35 years will be recruited. Older adults age 65-79 years will be&#xD;
      recruited.&#xD;
&#xD;
      At entry in the study, all subjects must self-report to be free from the following: history&#xD;
      of 1 or more falls in the previous year, ear infections, vertigo, Meniere's disease, chronic&#xD;
      dizziness. Subjects will not be excluded, but information will be collected on the following&#xD;
      factors: hip/knee replacements, pain in the body, body-mass index, daily physical activity&#xD;
      measures. A written informed consent approved by the Institutional Review Board of the&#xD;
      University of Nebraska Medical Center (the IRB of record) will be obtained prior to the&#xD;
      screening process.&#xD;
&#xD;
      Study Procedures Overview: Analysis of responses and falls from diverse slip perturbations&#xD;
      will take place in the main Motion Analysis Laboratory of the Biomechanics Research Building&#xD;
      at the University of Nebraska at Omaha. Each subject will participate in 3 visits within the&#xD;
      span of 1 week. On the initial visit, subjects will perform informed consent, then be asked&#xD;
      to provide demographic information (age, gender, height, body mass), a medical questionnaire&#xD;
      to assess exclusion criteria, and a physical activity questionnaire. Upper and lower body&#xD;
      strength will be measured using a hand-held dynamometer during the first and last visits. On&#xD;
      each of the three visits, subjects will perform a gait variability assessment followed by a&#xD;
      diverse slip perturbation assessment.&#xD;
&#xD;
      Gait variability assessment procedures: Before recording data, retroreflective markers will&#xD;
      be placed on specific anatomical locations. These locations are defined to create a full-body&#xD;
      dynamics model. Following familiarization, subjects will walk on a treadmill for 5 minutes at&#xD;
      a prescribed pace of 1.3 meters per second while whole body kinematics are collected. Both&#xD;
      linear and nonlinear measures of gait variability will be calculated (Table 1) to determine&#xD;
      possible relationships between these measures and other outcome variables such as learning&#xD;
      rate for reactive movements, and fall rate.&#xD;
&#xD;
      Diverse slip perturbation assessment procedures: subjects will walk overground back and forth&#xD;
      across a large motion capture area. Previous studies show that walking speed is highly&#xD;
      correlated with some outcome measures, specifically variations in whole body angular&#xD;
      momentum, gait variability measures, and loss of balance following a slip. Therefore, we will&#xD;
      control gait speed across all subjects to 1.3 ± 0.2 m/s, a typically comfortable speed for&#xD;
      both younger and older adults. Participants will be informed that a slip may occur, and that&#xD;
      if slipped, they should attempt to maintain balance and continue walking. Subjects will then&#xD;
      be slipped without warning at a randomly chosen time after 1 to 3 minutes of walking. Slips&#xD;
      will be administered to both feet simultaneously during early, middle or late stance in a&#xD;
      randomized order.&#xD;
&#xD;
      After each slip, subjects will rest seated for 5 minutes. During this rest period, motion&#xD;
      capture data and force data from the harness will be recorded, and the WASP will be reset for&#xD;
      the next trial. Subjects will complete four slips in each of early, middle, and late stance&#xD;
      on each visit. Measures of falls, slip severity, and reactive stabilization movements will be&#xD;
      calculated.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Recruiting</overall_status>
  <start_date type="Actual">December 1, 2019</start_date>
  <completion_date type="Anticipated">August 1, 2024</completion_date>
  <primary_completion_date type="Anticipated">January 1, 2024</primary_completion_date>
  <phase>Early Phase 1</phase>
  <study_type>Interventional</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <allocation>Non-Randomized</allocation>
    <intervention_model>Single Group Assignment</intervention_model>
    <primary_purpose>Basic Science</primary_purpose>
    <masking>None (Open Label)</masking>
  </study_design_info>
  <primary_outcome>
    <measure>Fall Percentage</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>Percentage of slip perturbations that result in a fall are assessed. Trials are classified as falls if the maximum force on the load cell in the harness system exceeds 30% body weight.</description>
  </primary_outcome>
  <secondary_outcome>
    <measure>Total Heel Displacement of the Slipping Foot Following Slip Perturbation</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>The total displacement of the slipping foot from the point of administered slip perturbation, until the foot stops sliding is assessed.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Trunk Angular Momentum Following Slip Perturbation</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>Angular momentum of the trunk is assessed during the period of time from the onset of slip perturbation until the subject recovers or falls.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Position of the Recovery Step Following Slip Perturbation</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>Position of the placement of the swing foot relative to the center of mass in the transverse plane following slip perturbation will be assessed.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Coefficient of Variation of Stride Time Time Series</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>The coefficient of variation of the time series of stride times during treadmill walking is assessed.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Maximum Heel Sliding Velocity of the Slipping Foot Following Slip Perturbation</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>The maximum velocity of the slipping foot will be assessed within the period from the administered slip perturbation, until the foot stops sliding.</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Time of the Recovery Step Following Slip Perturbation</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>Time of the placement of the swing foot relative to the onset of the administered slip perturbation is assessed</description>
  </secondary_outcome>
  <secondary_outcome>
    <measure>Sample Entropy of Stride Time Time Series</measure>
    <time_frame>Up to 7 days</time_frame>
    <description>The sample entropy of the time series of stride times during treadmill walking is assessed.</description>
  </secondary_outcome>
  <enrollment type="Anticipated">62</enrollment>
  <condition>Slip Perturbations</condition>
  <intervention>
    <intervention_type>Other</intervention_type>
    <intervention_name>Administered Slip Perturbations</intervention_name>
    <description>Slips will be administered in early, middle or late phases of stance during overground walking.</description>
  </intervention>
  <eligibility>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
          -  Age 19-35 years for younger adults group, or age 65-79 for older adults group.&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Uncontrolled hypertension&#xD;
&#xD;
          -  Peripheral arterial disease&#xD;
&#xD;
          -  Vertigo&#xD;
&#xD;
          -  Meniere's disease&#xD;
&#xD;
          -  Chronic dizziness&#xD;
&#xD;
          -  History of back or lower extremity injury&#xD;
&#xD;
          -  Surgery that affects the subject's mobility&#xD;
&#xD;
          -  Any neurological disease or impairment that affects limits the ability to walk, e.g.&#xD;
             Stroke, Parkinson's disease, Multiple sclerosis&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>19 Years</minimum_age>
    <maximum_age>79 Years</maximum_age>
    <healthy_volunteers>Accepts Healthy Volunteers</healthy_volunteers>
  </eligibility>
  <overall_contact>
    <last_name>Nathaniel H Hunt, Ph.D.</last_name>
    <phone>4025544195</phone>
    <email>nhunt@unomaha.edu</email>
  </overall_contact>
  <overall_contact_backup>
    <last_name>Angela Collins, B.S.</last_name>
    <phone>4025543228</phone>
    <email>afcollins@unomaha.edu</email>
  </overall_contact_backup>
  <location>
    <facility>
      <name>Biomechanics Research Building</name>
      <address>
        <city>Omaha</city>
        <state>Nebraska</state>
        <zip>68182</zip>
        <country>United States</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Nate Hunt, PhD</last_name>
      <phone>402-554-4195</phone>
      <email>nhunt@unomaha.edu</email>
    </contact>
  </location>
  <location_countries>
    <country>United States</country>
  </location_countries>
  <verification_date>May 2023</verification_date>
  <study_first_submitted>November 21, 2018</study_first_submitted>
  <study_first_submitted_qc>November 26, 2018</study_first_submitted_qc>
  <study_first_posted type="Actual">November 27, 2018</study_first_posted>
  <last_update_submitted>July 11, 2023</last_update_submitted>
  <last_update_submitted_qc>July 11, 2023</last_update_submitted_qc>
  <last_update_posted type="Actual">July 13, 2023</last_update_posted>
  <responsible_party>
    <responsible_party_type>Sponsor</responsible_party_type>
  </responsible_party>
  <patient_data>
    <sharing_ipd>Undecided</sharing_ipd>
    <ipd_description>This study will be registered at ClinicalTrials.gov prior to enrollment of the first subject. This will be completed by the PI. Research results will be made available in peer-reviewed publications, presentation at professional scientific conferences, uploaded to clinicaltrials.gov, and uploaded to the NCBI website, pubmed.gov. Informed consent documents will include a specific statement about posting clinical trial information at ClinicalTrials.gov. This will be complete by the PI. The University of Nebraska at Omaha makes every effort to adhere to the rules and recommendations regarding clinical trial registration and reporting.</ipd_description>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03755336
org study id: 0877-18-EP
nct id: NCT03755336
lead sponsor: 
has dmc: No
is fda regulated drug: No
is fda regulated device: No
To maintain mobility as we age we must navigate a complex environment that challenges us with
      a range of disturbances.

      Unfortunately, older adults are often unsuccessful in resisting these disturbances, and fall.
      Falls are the greatest source of injury, and for older adults, the greatest source of
      injury-related death. Approximately a quarter of falls happen following slips.

      Recent research on slips has shown that use of perturbation training to improve specific
      motor skills to resist slips can vastly reduce falls. However, these interventions have only
      addressed slips occurring at heel-strike, and not the diverse range of slipping disturbances
      presented by a complex environment. This project will focus on slips that occur across the
      gait cycle, and the reactive stabilization movements that follow. Slips at different phases
      of the gait cycle have unique biomechanical contexts, and successful reactive stabilization
      movements are likely to be highly specific to that context. Yet nothing is known about the
      specificity of the repertoire of reactive stabilization movements to resist different slip
      conditions. Furthermore, variability in the repertoire of reactive stabilization movements is
      likely to affect the success/failure rate of resisting these disturbances. Thus, the
      objective of the proposed project is to determine the roles of variability and specificity in
      reactive stabilization movements to resist falling in diverse slipping conditions. A novel
      wearable apparatus for slip perturbations will deliver lifelike, unexpected slips in early,
      middle and late stance in younger and older adults. Biomechanical analysis based on
      three-dimensional motion capture data of the reactive stabilization movements will generate
      novel results on the specificity and variability of protective stepping and arm swinging
      responses. The central hypothesis is that increases in specificity and decreases in
      variability of reactive stabilization movements will reduce fall rates. The first specific
      aim is to quantify variability and specificity of reactive responses to diverse slip
      perturbations and determine their relationships to fall rates. The second specific aim is to
      determine how repeated exposure to diverse slip perturbations affects reactive responses, and
      whether it relates to gait variability. The long-term objective of this research is to
      support future studies into the repertoire of reactive stabilization movements across the
      full range of disturbances faced in navigating the environment.
Subjects will be recruited through fliers from local exercise and community centers,
      independent senior living centers, and on the campus of the University of Nebraska at Omaha.
      Younger subjects age 19-35 years will be recruited. Older adults age 65-79 years will be
      recruited.

      At entry in the study, all subjects must self-report to be free from the following: history
      of 1 or more falls in the previous year, ear infections, vertigo, Meniere's disease, chronic
      dizziness. Subjects will not be excluded, but information will be collected on the following
      factors: hip/knee replacements, pain in the body, body-mass index, daily physical activity
      measures. A written informed consent approved by the Institutional Review Board of the
      University of Nebraska Medical Center (the IRB of record) will be obtained prior to the
      screening process.

      Study Procedures Overview: Analysis of responses and falls from diverse slip perturbations
      will take place in the main Motion Analysis Laboratory of the Biomechanics Research Building
      at the University of Nebraska at Omaha. Each subject will participate in 3 visits within the
      span of 1 week. On the initial visit, subjects will perform informed consent, then be asked
      to provide demographic information (age, gender, height, body mass), a medical questionnaire
      to assess exclusion criteria, and a physical activity questionnaire. Upper and lower body
      strength will be measured using a hand-held dynamometer during the first and last visits. On
      each of the three visits, subjects will perform a gait variability assessment followed by a
      diverse slip perturbation assessment.

      Gait variability assessment procedures: Before recording data, retroreflective markers will
      be placed on specific anatomical locations. These locations are defined to create a full-body
      dynamics model. Following familiarization, subjects will walk on a treadmill for 5 minutes at
      a prescribed pace of 1.3 meters per second while whole body kinematics are collected. Both
      linear and nonlinear measures of gait variability will be calculated (Table 1) to determine
      possible relationships between these measures and other outcome variables such as learning
      rate for reactive movements, and fall rate.

      Diverse slip perturbation assessment procedures: subjects will walk overground back and forth
      across a large motion capture area. Previous studies show that walking speed is highly
      correlated with some outcome measures, specifically variations in whole body angular
      momentum, gait variability measures, and loss of balance following a slip. Therefore, we will
      control gait speed across all subjects to 1.3 ± 0.2 m/s, a typically comfortable speed for
      both younger and older adults. Participants will be informed that a slip may occur, and that
      if slipped, they should attempt to maintain balance and continue walking. Subjects will then
      be slipped without warning at a randomly chosen time after 1 to 3 minutes of walking. Slips
      will be administered to both feet simultaneously during early, middle or late stance in a
      randomized order.

      After each slip, subjects will rest seated for 5 minutes. During this rest period, motion
      capture data and force data from the harness will be recorded, and the WASP will be reset for
      the next trial. Subjects will complete four slips in each of early, middle, and late stance
      on each visit. Measures of falls, slip severity, and reactive stabilization movements will be
      calculated.
allocation: Non-Randomized
intervention model: Single Group Assignment
primary purpose: Basic Science
masking: None (Open Label)
measure: Fall Percentage
time frame: Up to 7 days
description: Percentage of slip perturbations that result in a fall are assessed. Trials are classified as falls if the maximum force on the load cell in the harness system exceeds 30% body weight.
measure: Total Heel Displacement of the Slipping Foot Following Slip Perturbation
time frame: Up to 7 days
description: The total displacement of the slipping foot from the point of administered slip perturbation, until the foot stops sliding is assessed.
measure: Trunk Angular Momentum Following Slip Perturbation
time frame: Up to 7 days
description: Angular momentum of the trunk is assessed during the period of time from the onset of slip perturbation until the subject recovers or falls.
measure: Position of the Recovery Step Following Slip Perturbation
time frame: Up to 7 days
description: Position of the placement of the swing foot relative to the center of mass in the transverse plane following slip perturbation will be assessed.
measure: Coefficient of Variation of Stride Time Time Series
time frame: Up to 7 days
description: The coefficient of variation of the time series of stride times during treadmill walking is assessed.
measure: Maximum Heel Sliding Velocity of the Slipping Foot Following Slip Perturbation
time frame: Up to 7 days
description: The maximum velocity of the slipping foot will be assessed within the period from the administered slip perturbation, until the foot stops sliding.
measure: Time of the Recovery Step Following Slip Perturbation
time frame: Up to 7 days
description: Time of the placement of the swing foot relative to the onset of the administered slip perturbation is assessed
measure: Sample Entropy of Stride Time Time Series
time frame: Up to 7 days
description: The sample entropy of the time series of stride times during treadmill walking is assessed.
intervention type: Other
intervention name: Administered Slip Perturbations
description: Slips will be administered in early, middle or late phases of stance during overground walking.
criteria: 
gender: All
minimum age: 19 Years
maximum age: 79 Years
healthy volunteers: Accepts Healthy Volunteers
last name: Nathaniel H Hunt, Ph.D.
phone: 4025544195
email: nhunt@unomaha.edu
last name: Angela Collins, B.S.
phone: 4025543228
email: afcollins@unomaha.edu
facility: 
status: Recruiting
contact: 
country: United States
responsible party type: Sponsor
sharing ipd: Undecided
ipd description: This study will be registered at ClinicalTrials.gov prior to enrollment of the first subject. This will be completed by the PI. Research results will be made available in peer-reviewed publications, presentation at professional scientific conferences, uploaded to clinicaltrials.gov, and uploaded to the NCBI website, pubmed.gov. Informed consent documents will include a specific statement about posting clinical trial information at ClinicalTrials.gov. This will be complete by the PI. The University of Nebraska at Omaha makes every effort to adhere to the rules and recommendations regarding clinical trial registration and reporting.