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Evaluating a New Knee-Ankle-Foot Brace to Improve Crouch Gait in People With Cerebral Palsy

This study is currently recruiting participants.
Verified June 15, 2017 by National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier:
First Posted: October 11, 2013
Last Update Posted: October 19, 2017
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.
Information provided by (Responsible Party):
National Institutes of Health Clinical Center (CC)


- 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.

Cerebral Palsy

Study Type: Observational
Study Design: Observational Model: Case-Control
Time Perspective: Prospective
Official Title: Evaluating an Extension Assist Knee Ankle Foot Orthosis to Improve Crouch Gait in Cerebral Palsy

Resource links provided by NLM:

Further study details as provided by National Institutes of Health Clinical Center (CC):

Primary Outcome Measures:
  • Reduction in knee crouch (effectiveness) [ Time Frame: Assessed at Visit #2 and #6 while wearing devices ]
  • Subjective opinions about each brace option (tolerability/acceptability) [ Time Frame: Immediately after each use. ]

Estimated Enrollment: 40
Study Start Date: October 10, 2013
Estimated Study Completion Date: September 30, 2020
Estimated Primary Completion Date: September 30, 2020 (Final data collection date for primary outcome measure)
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) who have a crouch gait pattern. 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 variable resistance at the ankle joint which can also promote knee extension. 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 CP and of crouch gait. 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 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. The active motorized joint module and the two hybrid configurations have been evaluated by the FDA as non-significant risk to human subjects (Appendix F). Healthy controls will come for one visit, and participants with CP will complete 6 visits: 1) initial assessment and casting for custom leg brace; 2) EA-KAFO configuration and initial data collection; 3-5) accommodation to brace configurations; 6) final data collection. 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 crouch 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.


Information from the National Library of Medicine

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Ages Eligible for Study:   5 Years and older   (Child, Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
  • Age between 5 years and above
  • Either a healthy volunteer or have crouch gait with a diagnosis of spastic diplegic cerebral palsy
  • 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 crouch gait lacking at least 20 degrees of knee extension at mid stance during walking as assessed visually (exact level of crouch will be quantified after inclusion using gait analysis).
  • Able to walk at least 30 feet without stopping with or without a walking aid (GMFCS Level I-III)
  • Agreement to not drink caffeine for 24 hours before each EEG assessment visit because it can modify brain activity


-Any neurological, musculoskeletal or cardiorespiratory injury, health condition, or diagnosis other than cerebral palsy that would affect the ability to walk as directed for short periods of time.


-A history of a seizure in the past year.

  Contacts and Locations
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 ClinicalTrials.gov identifier (NCT number): NCT01961557

Contact: Thomas C Bulea, M.D. (301) 451-7533 buleatc@mail.nih.gov

United States, Maryland
National Institutes of Health Clinical Center, 9000 Rockville Pike Recruiting
Bethesda, Maryland, United States, 20892
Contact: For more information at the NIH Clinical Center contact Patient Recruitment and Public Liaison Office (PRPL)    800-411-1222 ext TTY8664111010    prpl@mail.cc.nih.gov   
Sponsors and Collaborators
National Institutes of Health Clinical Center (CC)
Principal Investigator: Thomas C Bulea, M.D. National Institutes of Health Clinical Center (CC)
  More Information

Additional Information:
Responsible Party: National Institutes of Health Clinical Center (CC)
ClinicalTrials.gov Identifier: NCT01961557     History of Changes
Other Study ID Numbers: 130210
First Submitted: October 10, 2013
First Posted: October 11, 2013
Last Update Posted: October 19, 2017
Last Verified: June 15, 2017

Keywords provided by National Institutes of Health Clinical Center (CC):
Cerebral Palsy

Additional relevant MeSH terms:
Cerebral Palsy
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Brain Damage, Chronic
Brain Diseases
Central Nervous System Diseases