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Evaluating a New Knee-Ankle-Foot Brace to Improve Gait in Children With Movement Disorders

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT01961557
Recruitment Status : Recruiting
First Posted : October 11, 2013
Last Update Posted : May 19, 2023
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC)

Brief Summary:


- Cerebral palsy (CP) is the most common motor disorder in children. CP often causes crouch gait, an abnormal way of walking. Knee crouch has many causes, so no single device or approach works best for everybody. This study s adjustable brace provides many types of walking assistance. Researchers will evaluate brace options to find the best solution for each participant, and whether one solution works best for the group.


- To evaluate a new brace to improve crouch gait in children with CP.


  • Children 5 17 years old with CP.
  • Healthy volunteers 5 17 years old.


  • All participants will be screened with medical history and physical exam.
  • Healthy volunteers will have 1 visit. They will do motion analysis, EMG, and EEG described below.
  • Participants with CP will have 6 visits.
  • Visit 1:

<TAB>1. Motion analysis: Balls will be taped to participants skin. This helps cameras follow their movement.

<TAB>2. EMG: Metal discs will be taped to participants skin. They measure electrical muscle activity.

<TAB>3. Participants knee movement will be tested.

<TAB>4. Participants will walk 50 meters.

<TAB>5. Participants legs will be cast to make custom braces.

  • Visit 2:
  • Participants will wear their new braces and have them adjusted.
  • Steps 1 3 will be repeated.
  • EEG: Small metal discs will be placed on the participants scalp. They record brain waves.
  • Participants will have electrical stimulation of their knees and practice extending them.
  • Participants will take several walks with the braces in different settings.
  • Visits 3 5: participants will repeat the walking and some other steps from visit 2.
  • Visit 6 will repeat visit 2.

Condition or disease Intervention/treatment Phase
Incomplete Spinal Cord Injury Muscular Dystrophy Spina Bifida Cerebral Palsy Device: EA-KAFO Not Applicable

Detailed Description:


The purpose of this protocol is to evaluate several configurations of a prototype Extension Assist Knee-Ankle-Foot Orthosis (EA-KAFO) in patients with cerebral palsy (CP), muscular dystrophy (MD), spina bifida (SB), or incomplete spinal cord injury (iSCI) who have knee extension deficiency. Three forms of assistance will be provided at the knee joint including a passive-damper component, functional electrical stimulation (FES) to the quadriceps, and a motorized assist. One form will provide controllable resistance at the knee to strengthen muscles and promote knee extension after the resistance is removed. These will be compared to traditional bracing which typically improves crouch by blocking some or all motion at one or both joints. We hypothesize that all assistive configurations will improve gait alignment and performance compared to the non-assisted conditions. We further hypothesize that a best solution for each participant will exist, but may vary across subjects due to the heterogeneity of these movement disorders. Preliminary data on brain activation using EEG will be collected during all walking conditions.

Study population

Thirty (30) subjects, age 5 and above, diagnosed with crouch gait from diplegic CP, (30) subjects, age 5 and above, with knee extension deficiency from MD, SB, or iSCI (15 from each group) and 10 age-matched healthy volunteers will be recruited.


This protocol will evaluate an EA-KAFO prototype consisting of a custom fabricated brace combined with a modular knee joint with three modes of operation: hinge (no assist), a passive spring-damper, and an active motorized assist. Since crouch can also be precipitated at the ankle, the orthotic ankle joint has an adjustable dynamic resistance (ADR) mechanism that can be locked (passive assist) to simulate a standard brace, free, or provide variable resistance to assist knee extension. Additionally, we will combine quadriceps FES with the hinge and the passive damper to create two hybrid configurations. The hinge and the passive damper (Ultraflex ) knee modules, and ADR ankle brace are FDA-approved (Class I), commercially available devices. This protocol for evaluation of the active motorized joint module, the two hybrid configurations, and the controllable resistance device (PowerWalk by Agilik Technologies) has been reviewed by the FDA as a medical device study and was determined by the FDA to be non-significant risk. Healthy controls will come for one visit, and participants with movement disorders will complete 6-10 visits: 1) initial assessment and casting for custom leg brace; 2) EA-KAFO configuration; 3) initial data collection and practice; 4-5) accommodation to brace configurations; 6) final data collection. Additional accommodation visits may be added if necessary, up to the maximum of 10 total visits. Participants with movement disorders will be permitted to re-enroll in the protocol is a minimum of 1 year has passed from their prior final visit. Motion capture, force plates, and electromyography (EMG) will be used for gait analysis while electroencephalography (EEG) will measure brain activity during walking.

Outcome measures

The primary outcome is the amount of knee flexion during gait. The optimal solution for each individual will be that which provides the greatest reduction in peak knee angle. Secondary outcomes will include gait speed, knee extensor moment, and EEG activation profiles.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 85 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Device Feasibility
Official Title: Evaluating an Extension Assist Knee Ankle Foot Orthosis to Improve Gait in Children With Movement Disorders
Actual Study Start Date : July 2, 2015
Estimated Primary Completion Date : January 31, 2024
Estimated Study Completion Date : December 31, 2025

Arm Intervention/treatment
Experimental: There is a single study arm in this feasibility study.
All participants will be evaluated using the different configurations of the EA-KAFO (see Table 1 in the protocol), which includes the configuration that contains the Active Motorized KAFO and the configuration that contains the Powerwalk Knee Exoskeleton. Each subject will serve as their own control to assess the effect of each configuration of the EA-KAFO interventions.
Device: EA-KAFO
This study tests a single device that contains multiple potential configurations as outlined in Table 1 of the protocol. Each participant be evaluated in multiple configurations, minimally including the baseline configuration and the motor assist condition at the knee.

Primary Outcome Measures :
  1. Peak knee angle [ Time Frame: This outcome will be assessed twice, at the initial and final data assessment visits, as indicated in the protocol. ]
    The primary outcome measure will be the effect of the intervention on crouch, as measured by peak knee angle during walking with the EA-KAFO. the outcome description refers to the general Extension Assist Knee Ankle Foot Orthosis (EA-KAFO). The outcome measure will be assessed across the different configurations of the EA-KAFO, which includes the configuration that contains the Active Motorized KAFO and the configuration that contains the Powerwalk Knee Exoskeleton.

Secondary Outcome Measures :
  1. Secondary outcome measures [ Time Frame: At the same time ]
    Secondary outcome measures, assessed at the same time frame and across the same configurations of the EA-KAFO as the primary outcome measure, include Gait Speed and Knee Joint Moment.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   5 Years and older   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
  • Age 5 years and above
  • Either a healthy volunteer, have crouch gait with a diagnosis of spastic diplegic cerebral palsy, or have lower extremity weakness resulting in gait pathology from a diagnosis of muscular dystrophy, spina bifida, or incomplete spinal cord injury.
  • Able to understand and follow simple directions based on parent report and physician observation during history and physical examination.
  • Able to provide verbal/written assent.
  • Less than 5 degrees of knee flexion contracture with hip extended in supine position. Hamstring contracture as assessed by straight leg raising test does not limit ability to participate in the study.
  • Less than 10 degrees of plantar flexion contracture in neutral foot alignment.
  • A measured foot-thigh angle of -10 to 25 degrees in prone position.
  • Diagnosed with knee extension deficiency as indicated by a crouched posture during gait lacking at least 20 degrees of knee extension at mid stance during walking as assessed visually, knee extensor muscle weakness which prevents full extension of the limb, or reliance upon braces or other aids which lock the knee during walking. (The exact level of knee extension deficiency, or crouch, will be quantified after inclusion using gait analysis.)
  • Able to walk at least 10 feet without stopping with or without a walking aid
  • Agreement to not drink caffeine for 24 hours before each EEG assessment (CP only) visit because it can modify brain activity


  • Any neurological, musculoskeletal or cardiorespiratory injury, health condition, or diagnosis other than cerebral palsy, muscular dystrophy, spina bifida, or incomplete spinal cord injury that would affect the ability to walk as directed for short periods of time.
  • Participation in this protocol within the previous 1 year.


  • A history of a seizure in the past year.
  • Pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01961557

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Contact: Jesse H Matsubara (301) 451-7530
Contact: Thomas C Bulea, M.D. (301) 451-7533

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United States, Maryland
National Institutes of Health Clinical Center Recruiting
Bethesda, Maryland, United States, 20892
Contact: For more information at the NIH Clinical Center contact Office of Patient Recruitment (OPR)    800-411-1222 ext TTY dial 711   
Sponsors and Collaborators
National Institutes of Health Clinical Center (CC)
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Principal Investigator: Thomas C Bulea, M.D. National Institutes of Health Clinical Center (CC)
Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: National Institutes of Health Clinical Center (CC) Identifier: NCT01961557    
Other Study ID Numbers: 130210
First Posted: October 11, 2013    Key Record Dates
Last Update Posted: May 19, 2023
Last Verified: March 3, 2023
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Plan Description: .Protocol is silent about sharing IPD.

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Keywords provided by National Institutes of Health Clinical Center (CC):
incomplete spinal cord injury
Cerebral Palsy
Muscular Dystrophies
Additional relevant MeSH terms:
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Muscular Dystrophies
Spinal Cord Injuries
Cerebral Palsy
Movement Disorders
Spinal Dysraphism
Spinal Cord Diseases
Central Nervous System Diseases
Nervous System Diseases
Trauma, Nervous System
Wounds and Injuries
Brain Damage, Chronic
Brain Diseases
Muscular Disorders, Atrophic
Muscular Diseases
Musculoskeletal Diseases
Neuromuscular Diseases
Genetic Diseases, Inborn
Neural Tube Defects
Nervous System Malformations
Congenital Abnormalities