FES to Improve Gait in CP

Shriners Hospitals for Children2 enrolled

Overview

The goal of this proposal is to mitigate the typical decline in walking function experienced by children with cerebral palsy (CP) via a Functional Electrical Stimulation (FES)-assisted treadmill training intervention. In this study, the investigators intend to use thier CP FES Gait Training System to assess the neurotherapeutic effects of an FES-assisted treadmill training intervention on walking performance in children with CP. The research design consists of a randomized, controlled, two-treatment study in which the control subjects will cross-over into one of the two treatment groups. An FES-assisted training group will undergo twelve weeks of FES-assisted treadmill training using a distributive practice protocol consisting of alternating bouts of walking with and without FES assistance, followed by over ground walking reinforcement. A treadmill-only training group will undergo the same training regimen without FES-assistance. Finally, a non-intervention group will serve as a control. The investigators will analyze treatment efficacy via functional and biomechanical and measures collected pre-training, post-training and after a twelve-week follow-up period.

Aim 1: Assess the neurotherapeutic effects of FES-assisted treadmill and treadmill-only training on walking function relative to each other and to the control group. 1.1 The FES-assisted treadmill and treadmill-only groups will demonstrate greater improvements in walking speed and walking distance than the control group post-training and at follow-up. The FES-assisted treadmill group will show greater improvements than the treadmill-only group. 1.2 The FES-assisted treadmill and treadmill-only groups will demonstrate greater improvement in walking energy efficiency than the control group post-training and at follow-up. The FES-assisted treadmill group will show greater improvement than the treadmill-only group. 1.3 The FES-assisted treadmill and treadmill-only groups will demonstrate greater improvements in GMFM, perceived functional mobility, quality of life and self-perception measures than the control group post-training and at follow-up. The FES-assisted treadmill group will show greater improvements than the treadmill-only group. Aim 2: Assess the differential neurotherapeutic effects of FES-assisted treadmill and treadmill-only training on walking biomechanics. The investigators will measure these effects using instrumented motion capture. 2.1 The FES-assisted treadmill group will demonstrate greater improvements in gait kinematics in stance phase (higher peak hip and knee extension and lower peak ankle dorsiflexion) and swing phase (higher peak knee extension and larger knee excursion) than the treadmill only and non-intervention groups 2.2 The FES-assisted treadmill group will demonstrate greater improvements in lower extremity kinetics (lower hip and knee extensor moments and increased ankle plantarflexion power) than the treadmill only and non- intervention groups. 2.3 The FES-assisted treadmill group will demonstrate greater improvements in spatiotemporal gait parameters (increased step length and gait velocity, decreased step width and double support time) than the treadmill- only and control groups. Aim 3: Identify predictive measures of training efficacy. 3.1 Pre-training walking speed and energy efficiency will correlate with improvements in walking performance measures of Aim 1. 3.2 Increased neuroprosthetic correction of gait biomechanics measures achieved by FES will be positively correlated with walking performance measures of Aim 1.

Interventions

Functional Electrical Stimulation protocolOTHER

FES-assisted treadmill walking followed by a 12-week follow-up period. Subjects will train three times a week walking at a target speed corresponding to 60-80% of their age-predicted maximum heart rate. Each training session will consist of five six-minute walking bouts, with five-minute rest periods between bouts. Each treadmill bout consists of alternating one- minute intervals of FES on and FES off. For the last walking bout, the first three minutes will be FES-assisted on the treadmill and the last three minutes will be overground walking without FES assistance to promote carryover effects. Total walking time is 30 minutes and the entire training session lasts approximately 50 minutes.

Treadmill only protocolOTHER

We will implement a 12-wk Treadmill training protocol consisting of treadmill walking followed by a 12-week follow-up period. Subjects will train three times a week walking at a target speed corresponding to 60-80% of their age. Each training session will consist of five six-minute walking bouts, with five-minute rest periods between bouts. Total walking time is 30 minutes and the entire training session lasts approximately 50 minutes.

Eligibility

Sex: ALLMin age: 10 YearsMax age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age 10-18 * Diagnosis of spastic diplegic CP * Gross Motor Functional Classification Scale (GMFCS) level I-III * Hip migration \< 40% * Displays crouch, equinus, or jump type gait * At least 0° passive dorsiflexion range of motion (can come to a neutral position) * Sufficient visuoperceptual, cognitive and communication skills * Seizure-free or well-controlled seizures * No other neurological or musculoskeletal disorders (e.g. dystonia, severe scoliosis, hip instability) * Ability to travel to University of Delaware or Shriners Hospital for children multiple times per week for training and assessment * Ability to communicate pain or discomfort * Ability to consent (if 18 years old) or obtain parent/guardian consent (if under 18) Exclusion Criteria: * Diagnosis of athetoid or ataxic CP * Scoliosis with primary curve \> 49% * Spinal fusions extending into pelvis * Lower Extremity (LE) joint instability or dislocation * Severe tactile hypersensitivity * LE botulinum (Botox) injections in the past 6 mo. * Implanted medical device contraindicative of FES * Pregnancy * Severe LE spasticity (Modified Ashworth Scale score of 4 or greater) * History of pulmonary disease limiting exercise tolerance (Asthma Control screen) * History of cardiac disease (AHA screen) * Excessive LE joint pain during walking * Severely limited joint range of motion / irreversible muscle contractures, i.e.\> 10°knee flexion, \>15° hip flexion contractures, or \>5° plantarflexion contractures * LE surgery or significant injury within 1 yr.

Outcomes

Primary Outcomes

Muscle Tone

We use the Modified Ashworth Scale to measure resistance to passive movement about a joint with varying degree of velocity (Muscle tone/spasticity). Score ranges from 0-4, with 6 choices where score of 0 means no increase in tone and score of 4 means rigid limb with no flexion or extension. Our training approach using repetitive electrical stimulation may also lower spasticity, which can also facilitate improved functional mobility.

Time frame: Three assessment points in time: a Pre Assessment before beginning training (Week 1), a Post Assessment following training (Week 14), and a Follow-Up Assessment twelve weeks after completion of training (Week 27).

Walking Speed

Walking speed is an indicator of functional mobility. By our training methods, we hypothesize making improvements in motor learning and gait biomechanics. Improved walking speed would indicate that such improvements have occurred.

Walking Distance

Walking distance (in a fixed period of time) is an indicator of endurance. Improved motor learning and gait biomechanics from our training methods would improve gait efficiency and thus, endurance.

Energy Expenditure

Energy expenditure is a measure of cardiovascular fitness and walking efficiency. By means of exercise at 60-80% max heart rates, it is expected that cardiovascular fitness would improve. Energy expenditure measurements allow for measurement of cardiovascular fitness.

Gross Motor Function Measure

Gross Motor Function Measure (GMFM) is a measure of motor function that indicates disablement. Improved motor control and gait biomechanics from training should be reflected in overall gross motor function, which is assessed via the GMFM.

Balance Evaluation Systems Test

Balance Evaluation Systems Test (BESTest) is a measure of balance function. The BESTest will allow for assessing the impact of anticipated improvements in motor control and gait biomechanics from training on balance.

Timed Up-And-Go

Timed Up-And-Go (TUG) is a measure of functional mobility and will allow for assessing the impact of anticipated improvements in motor control and gait biomechanics.

Instrumented Gait Analysis

Joint Kinematics

Electromyography

Muscle activation timing measured with electromyography during gait analysis allows for mechanistic study of anticipated improvements in motor control and gait as well as comparison to typical norms.

Activities-Specific Balance Scale

The Activities-Specific Balance Scale (ABC Scale) survey allows measurement of perceived functional mobility by assessing balance confidence to perform daily activities of living without falling. 16 items are rated on a rating scale with range of 0-100. Score of 0 means no confidence and 100 means complete confidence. Average score of 16 items is the overall score. Such measures will assess the impact of anticipated improvements in motor control and gait bio-mechanics from training.

Participation in Life Events

Participation in life events (LIFE-H) survey measures how much a person is engaging or participating with their peers and community. Weighted score ranges between 0-10 with 0 score being no accomplishment and 10 means complete accomplishment. Such measures will assess the impact of anticipated improvements in motor control and gait biomechanics from training.

Self-Perception

Self-Perception (Piers-Harris-2) survey measures physical and emotional well-being and self-esteem and will allow assessment of the impact of anticipated improvements in motor control and gait biomechanics from training.