Trial Summary
What is the purpose of this trial?Objective: The goal of this study is to implement and test a neuro-mechanical gait assist (NMGA) device to correct walking characterized by muscle weakness, incoordination or excessive tone in Veterans with hemiparesis after stroke that adversely affects their ability to walk, exercise, perform activities of daily living, and participate fully in personal, professional and social roles.
Research Plan: A prototype NMGA device will be used to develop a finite state controller (FSC) to coordinate each user's volitional effort with surface muscle stimulation and motorized knee assistance as needed. Brace mounted sensors will be used to develop a gait event detector (GED) which will serve the FSC to advance through the phases of gait or stair climbing. In addition, a rule-base intent detection algorithm will be developed using brace mounted sensors and user interface input to select among various functions including walking, stairs climbing, sit-to-stand and stand-to-sit maneuvers. The FSC controller tuning and intent algorithm development and evaluation will be on pilot subjects with difficulty walking after stroke. Outcome measures during development will provide specifications for a new prototype NMGA design which will be evaluated on pilot subjects to test the hypothesis that the NMGA improves walking speed, distance and energy consumption of walking. These baseline data and device will be used to design a follow-up clinical trial to measure orthotic impact of NMGA on mobility in activities of daily living at home and community.
Methodology: After meeting inclusion criteria, pilot subjects will undergo baseline gait evaluation with EMG activities of knee flexors and extensors, ankle plantar and dorsiflexors and isokinetic knee strength and passive resistance. They will be fitted with a NMGA combining a knee-ankle-foot-orthosis with a motorized knee joint and surface neuromuscular stimulation of plantar- and dorsi- flexors, vasti and rectus femoris. Brace mounted sensor data will be used for gait event detector (GED) algorithm development and evaluation. The GED will serve the FSC to proceed through phases of gait based on supervisory rule-based user intent recognition algorithm detected by brace mounted sensors and user input interface. The FSC will coordinate feed-forward control of tuned stimulation patterns and closed-loop controlled knee power assist as needed to control foot clearance during swing and stability of the knee during stance. Based on data attained during controller development and evaluation, a new prototype NMGA will be design, constructed and evaluated on pilot subjects to test the hypothesis that a NMGA device improves safety and stability, increases walking speed and distance and minimizes user effort.
Clinical Significance: The anticipated outcome is improved gait stability with improved swing knee flexion, thus, increasing the safety and preventing injurious falls of ambulatory individuals with hemiplegia due to stroke found in large and ever-increasing numbers in the aging Veteran population. Correcting gait should lead to improved quality of life and participation.
Eligibility Criteria
This trial is for Veterans with hemiparesis after a stroke, who can walk at least 10ft with some help and have enough upper body function to use a cane. They should be over 6 months post-stroke and have specific ranges of motion in their hips and ankles. People with severe muscle tone issues, joint contractures, infections, pregnancy, certain heart conditions or severe cognitive impairments cannot participate.Inclusion Criteria
I can use a cane with my arms.
I can move my ankle up to a neutral position without help when my leg is straight.
I can lift my knee toward my chest at least halfway.
+6 more
Exclusion Criteria
My knee is very stiff, needing a lot of force to bend.
I have stiffness in my ankles and hips that limits their movement.
Pregnancy
+12 more
Participant Groups
The study tests a new device called NMGA that helps correct walking problems caused by strokes. It combines leg braces with motorized knee joints and electrical muscle stimulation. The goal is to improve walking speed, distance covered, energy used when walking, safety and stability.
1Treatment groups
Experimental Treatment
Group I: Neuromechanical Gait AssistExperimental Treatment1 Intervention
All participants will participate in developing controllers to coordinate device assistance with walking ability. Walking will be compared before gait training and after gait training. Walking will be evaluated both with and without device assistance.
Find a Clinic Near You
Research Locations NearbySelect from list below to view details:
Louis Stokes VA Medical Center, Cleveland, OHCleveland, OH
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Who Is Running the Clinical Trial?
VA Office of Research and DevelopmentLead Sponsor