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Toward a hybrid exoskeleton for crouch gait in children with cerebral palsy: neuromuscular electrical stimulation for improved knee extension
- Source :
- Journal of NeuroEngineering and Rehabilitation, Vol 17, Iss 1, Pp 1-14 (2020), Journal of NeuroEngineering and Rehabilitation
- Publication Year :
- 2020
- Publisher :
- BMC, 2020.
-
Abstract
- Background Neuromuscular Electrical Stimulation (NMES) has been utilized for many years in cerebral palsy (CP) with limited success despite its inherent potential for improving muscle size and/or strength, inhibiting or reducing spasticity, and enhancing motor performance during functional activities such as gait. While surface NMES has been shown to successfully improve foot drop in CP and stroke, correction of more complex gait abnormalities in CP such as flexed knee (crouch) gait remains challenging due to the level of stimulation needed for the quadriceps muscles that must be balanced with patient tolerability and the ability to deliver NMES assistance at precise times within a gait cycle. Methods This paper outlines the design and evaluation of a custom, noninvasive NMES system that can trigger and adjust electrical stimulation in real-time. Further, this study demonstrates feasibility of one possible application for this digitally-controlled NMES system as a component of a pediatric robotic exoskeleton to provide on-demand stimulation to leg muscles within specific phases of the gait cycle for those with CP and other neurological disorders who still have lower limb sensation and volitional control. A graphical user interface was developed to digitally set stimulation parameters (amplitude, pulse width, and frequency), timing, and intensity during walking. Benchtop testing characterized system delay and power output. System performance was investigated during a single session that consisted of four overground walking conditions in a 15-year-old male with bilateral spastic CP, GMFCS Level III: (1) his current Ankle-Foot Orthosis (AFO); (2) unassisted Exoskeleton; (3) NMES of the vastus lateralis; and (4) NMES of the vastus lateralis and rectus femoris. We hypothesized in this participant with crouch gait that NMES triggered with low latency to knee extensor muscles during stance would have a modest but positive effect on knee extension during stance. Results The system delivers four channels of NMES with average delays of 16.5 ± 13.5 ms. Walking results show NMES to the vastus lateralis and rectus femoris during stance immediately improved mean peak knee extension during mid-stance (p = 0.003*) and total knee excursion (p = 0.009*) in the more affected leg. The electrical design, microcontroller software and graphical user interface developed here are included as open source material to facilitate additional research into digitally-controlled surface stimulation (github.com/NIHFAB/NMES). Conclusions The custom, digitally-controlled NMES system can reliably trigger electrical stimulation with low latency. Precisely timed delivery of electrical stimulation to the quadriceps is a promising treatment for crouch. Our ultimate goal is to synchronize NMES with robotic knee extension assistance to create a hybrid NMES-exoskeleton device for gait rehabilitation in children with flexed knee gait from CP as well as from other pediatric disorders. Trial registration clinicaltrials.gov, ID: NCT01961557. Registered 11 October 2013; Last Updated 27 January 2020.
- Subjects :
- Male
030506 rehabilitation
medicine.medical_specialty
Foot drop
Functional electrical stimulation (FES)
Adolescent
Knee Joint
medicine.medical_treatment
Powered exoskeleton
Electric Stimulation Therapy
Health Informatics
Prosthesis Design
Cerebral palsy
lcsh:RC321-571
Graphical user interface (GUI)
03 medical and health sciences
Physical medicine and rehabilitation
Gait (human)
Spastic
Humans
Medicine
Spasticity
lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry
Gait Disorders, Neurologic
Rehabilitation
business.industry
Cerebral Palsy
Research
Exoskeleton Device
medicine.disease
Crouch gait
Exoskeleton
Muscle Spasticity
medicine.symptom
0305 other medical science
business
human activities
Subjects
Details
- Language :
- English
- ISSN :
- 17430003
- Volume :
- 17
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Journal of NeuroEngineering and Rehabilitation
- Accession number :
- edsair.doi.dedup.....29c600d42c65c202bfd40ee4458da890