Testing an Adjustable Ankle Orthosis During Walking in Cerebral Palsy

An Adjustable Stiffness Orthosis to Maintain Muscle Engagement and Push-off Power in Cerebral Palsy

This study seeks to determine how an adjustable stiffness ankle braces affects walking performance and biomechanics in cerebral palsy.

Study Overview

• Status: Completed
• Conditions: Cerebral Palsy
• Intervention / Treatment: Device: Differential and adjustable stiffness AFO (DAS-AFO)

Detailed Description

Our first aim is to confirm that the differential and adjustable stiffness (DAS) AFO improves plantarflexor push-off power and range of motion compared to standard (physician prescribed) AFOs during walking in CP.

Our second aim is to confirm that the differential and adjustable stiffness (DAS) AFO improves plantarflexor muscle activity while maintaining improved posture compared to standard AFOs during walking in CP.

Our third aim is to validate the need and usability of real-time stiffness adjustment during play and school activities; obtain feedback from the children, their parents, and orthotists to design the MVP.

• Study Type: Interventional
• Enrollment (Actual): 11
• Phase: Early Phase 1

Contacts and Locations

Study Locations

• United States
  • Arizona
    • Flagstaff, Arizona, United States, 86011
      • Northern Arizona University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 8-35 years old, inclusive
• Diagnosis of cerebral palsy (CP)
• Gross motor functional classification score level I, II, or III
• Physician-prescribed AFOs of common design (i.e., rigid molded thermoplastic)
• Ability to walk for 6 minutes on a treadmill
• At least 20° of passive plantar-flexion range of motion
• No concurrent treatment other than those assigned during the study
• No condition other than CP that would affect safe participation
• No surgery within 6 months of participation.

Exclusion Criteria:

-Excessive knee flexion during walking caused by CP

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Study group; Participants will walk with the new AFO, their own AFOs, and no AFOs.	Device: Differential and adjustable stiffness AFO (DAS-AFO); Walking with a differential and adjustable stiffness AFO (DAS-AFO)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Muscle Activity	Change in integrated soleus electromyography (mV/mV) muscle activity during stance phase of walking.	day 1
Change in Metabolic Cost of Transport	Change in metabolic cost of transport during walking. To calculate the metabolic cost of transport, the standing baseline metabolic rate for each participant and each trial was subtracted from their walking metabolic rate to estimate the net metabolic rate of walking. Next, we normalized the net metabolic rate of walking by each participant's body mass (m) and walking speed to calculate the metabolic cost of transport (J/kg*m), averaged over the last two minutes of each condition.	day 1
Change in Ankle Power	Change in peak ankle power during stance phase measured in w/kg. Ankle kinematics and kinetics were calculated in OpenSim using the collected three-dimensional motion capture and the ground reaction forces. The joint kinematics and ground reaction forces were filtered using a low pass fourth order recursive Butterworth filter with a cut-off frequency of 6 Hz before being used to calculate joint kinetics. The ground reaction forces were collected using two force places associated with the instrumented treadmill (Bertec Corp, Columbus, USA) collected at 1200 Hz. The resultant joint kinetics were then further filtered using the same filtering parameters. Ankle joint power was calculated as the product of the joint moment and joint angular velocity.	1 day during walking

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pictorial Children's Effort Rating Table (PCERT)	Pictorial Children's Effort Rating Table (PCERT) score (Range: 0:10; higher score means higher exertion)	day 1
System Usability Score (SUS) questionnaire	System Usability Scale Score (Range: 0:100; higher score means better usability)	day 1

Collaborators and Investigators

• Sponsor: Northern Arizona University

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2024
• Primary Completion (Actual): June 1, 2024
• Study Completion (Actual): June 1, 2024

Study Registration Dates

• First Submitted: January 29, 2024
• First Submitted That Met QC Criteria: February 8, 2024
• First Posted (Actual): February 15, 2024

Study Record Updates

• Last Update Posted (Actual): May 25, 2025
• Last Update Submitted That Met QC Criteria: May 22, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Brain Damage, Chronic; Cerebral Palsy
• Other Study ID Numbers: 2137249

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No