Functional Electrical Stimulation During Walking in Cerebral Palsy

Study Overview
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Brief Summary
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Children with spastic cerebral palsy (CP) often walk with insufficient ankle dorsiflexion in the swing phase. A pathological gait, known as drop-foot gait, can be the result and this has 2 major complications: foot-slap during loading response and toe-drag during swing. This is partly caused by weakness of the anterior tibial muscle and partly due to co-contraction of both the fibular- and anterior tibial muscle. For classification of gait, the Winters scale can be used, where unilateral CP with dropfoot is classified as type I. In daily life these problems cause limited walking distance and frequent falls, leading to restrictions in participating in daily life. The current guideline for spastic cerebral palsy describes the following therapies: 1) conservative therapy (physiotherapy, orthopaedic shoes and orthoses) 2) drugs suppressing spasticity 3) surgical interventions. Functional electrical stimulation (FES) may be an effective alternative treatment for children with spastic CP and a drop foot. By stimulating the fibular nerve or the anterior tibial muscle directly during the swing phase, dorsiflexion of the foot is stimulated. In contrast to bracing, FES does not restrict motion, but does produce muscle contraction, and thus has the potential to increase strength and motor control through repetitive neural stimulation over time. In a systematic review the investigators found that FES immediately improves ankle dorsal flexion and reduces falls and these effects also sustain. However, it should be noted that the level of evidence is limited. Until now, the use of FES in CP is limited and no data exist about the effects on walking distance (activity level) and participation level. The overall objective of this study is to conduct a randomised cross-over intervention trial in children with unilateral spastic CP with 12 weeks of FES (for every participant) and 18 weeks of conventional therapy. The effectiveness of FES will be examined at participation leven, using individual goal attainment. Next to that the effect at gait will be measured. An additional goal is to investigate the cost effectiveness of FES, which, in case of a positive effect, may support allowance by insurance companies.

Detailed Description
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Children with spastic cerebral palsy often walk with insufficient ankle dorsiflexion in the swing phase or with eversion of the foot. A pathological gait, known as drop-foot gait, can be the result and this has 2 major complications: foot-slap during loading response and toe-drag during swing. This is partly caused by weakness of the anterior tibial muscle and partly due to co-contraction of both the fibular- and anterior tibial muscle. In time, the disorder appears to be progressive due to atrophy and contractures of the muscle and increasing bodyweight. For classification of gait, the Winters scale can be used, where unilateral CP with dropfoot is classified as type I. In daily life these problems cause limited walking distance and frequent falls. This can lead to restrictions in participating in daily activities at school and in leisure. The current guideline for spastic cerebral palsy describes the following therapies: 1) conservative therapy, which includes physiotherapy, orthopaedic shoes and orthoses. 2) systemically and locally applied drugs suppressing spasticity. 3) surgical interventions, e.g. tenotomy, transposition and osteotomy. In each intervention, there is the risk of side effects, such as sedation with oral medications, pressure sores and atrophy in a static orthosis, temporary effect in a Botulinum toxin A treatment and surgical complications due to a result of the surgery, and on the other hand as a result of the execution. Functional electrical stimulation (FES) may be an effective alternative treatment for children with spastic CP and a drop foot. By stimulating the fibular nerve or the anterior tibial muscle directly during the swing phase, dorsiflexion of the foot is stimulated. In contrast to bracing, FES does not restrict motion, but does produce muscle contraction, and thus has the potential to increase strength and motor control through repetitive neural stimulation over time. In a systematic review the investigators found that FES immediately improves ankle dorsal flexion and falls. In addition, longer sustained effects of FES on ankle dorsal flexion and falls are found. However, it should be noted only two study studies (4 articles) were of level II class evidence (small RCT) and all other studies used a single subject design. Until now, the use of FES in CP is limited and no data exist about the effects on walking distance (activity level) and participation level. The overall objective of this study is to conduct a randomised cross-over intervention trial in children with unilateral spastic CP with 12 weeks of FES for every participant and 18 weeks of conventional therapy. The effectiveness of FES will be examined at participation leven, using individual goal attainment. With every individual a goal at walking distance will be set, next to possible other goals. Next to that, results will be measured at the activity and functional level: the effect at gait kinematics (such as ankle dorsiflexion and balance), walking distance, falls, spasticity and muscle force. The type of brain damage of the patients is also taken in to account. An addition al goal is to investigate the cost effectiveness of FES, which, in case of a positive effect, may support allowance by insurance companies.

Official Title
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Functional Electrical Stimulation of the Ankle Dorsiflexors During Walking in Children With Unilateral Spastic Cerebral Palsy: a Randomized Crossover Intervention Study

Conditions
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Cerebral Palsy, Spastic, Foot Drop

Intervention / Treatment
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* Device: FES


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Unilateral foot drop of central origin, particularly the absence of initial heel contact Participants are currently treated with ankle-foot orthoses or (adapted) shoes to wear on a daily basis Participants ambulate independently, and thus classified as Gross Motor Function Classification System (GMFCS) levels I or II and have a gait type 1 according to Winters et al (4). Participants are able to walk for at least 15 minutes Confirmed cerebral abnormality with MRI (showing medial infarction, maldevelopment of the brain, or porencephaly). Participants are aged 4-18 years at time of inclusion Exclusion Criteria: Plantarflexion ankle contracture of more than 5 degrees plantarflexion with the knee extended Botulinum toxin A injection to the plantar or dorsiflexor muscle groups within the 6 months before the study Orthopaedic surgery to the legs in the previous year Uncontrolled epilepsy with daily seizures

Ages Eligible for Study
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Minimum Age: 4 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: randomisation for the order of treatments and thereby for the total length of the 'conventional therapy phase'.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: FES start<br>Start: 4 weeks 'adaptation phase' and 8 weeks 'FES phase'. Adaption phase: the stimulus (in Volt) will gradually be increased up to an effective level and the wear time has to be increased from 30 minutes to 6 hours a day. FES phase: the participants have to wear the FES device for minimal 6 hours a day during walking. Usual physiotherapy can be continued during the FES phase. Second: after the FES phase, this group will enter the 'wash-out' period of 6 weeks for fading of the therapeutic effects, in which they return to their conventional therapy. Afterwards, 12 weeks of conventional therapy (orthoses/shoes and usual physiotherapy) with measurements at start and end will follow. | Device: FES<br>* Functional electrical stimulation of the ankle dorsiflexors during walking, using a (superficial) neurostimulator with tilt sensor.<br>|
| Other: Conventional start<br>Start: wearing usual orthoses/shoes on a daily basis for the first 12 weeks of the study. Usual physiotherapy can be continued. Second: after 12 weeks this group will enter a 6 week watch out phase, and next be switched to FES treatment for 12 weeks, consisting of: 4 weeks 'adaptation phase' with gradual increase of the treatment and 8 weeks 'FES phase'. | Device: FES<br>* Functional electrical stimulation of the ankle dorsiflexors during walking, using a (superficial) neurostimulator with tilt sensor.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in goal attainment scale (GAS) | Goal attainment scale: definition of an individual goal at start, followed by a 6- point numeric scale indicating to what extent the goal is (score 0 till +2) or is not (-3 indicating detoriation till -1) reached. | Setting of goal(s) at start, assessment at every end of a phase: week 12, 18 and 30. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in participation | as measured in the Cerebral Palsy Quality of Life Questionnaire (see reference). | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in walking distance | Measured by the 6 minute walking test and the functional mobility scale (3 items, 6-point rating scale). | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in physical activity | measured by activity monitor | assessment at start and end of a phase (except for the wash-out phase): week 12 and 30. | 
| Change in frequency of falling | measured by a questionnaire | assessment at every end of a phase: week 12, 18 and 30. | 
| Change in stability during walking | measured by variation of center of mass and margins of stability assessed during 3D gait analysis | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in ankle dorsiflexion angle | measured in degrees during gait analysis during 3D gait analysis | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in calf muscle activation | Assessed by spasticity measurement and electromyography (EMG) during 3D gait analysis | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in ankle plantarflexion strength during walking | Calculated by net push off moments during 3D gait analysis | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in ankle dorsiflexion and plantarflexion strength | measured in Newton by handheld dynamometer | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in feelings about donning and doffing | measured by a questionnaire | assessment at start and every end of a phase: week 12, 18 and 30. | 
| Change in patient satisfaction | measured by a visual analogue scale with smileys (0 = unsatisfied, 6 = perfectly satisfied). | assessment at start and every end of a phase: week 12, 18 and 30. | 
| The compliance and acceptability of FES | derived from delivered stimulations and hours of wear time in the log file | the FES devices measures this automatically during wearing; so this will happen during the 12 weeks of FES therapy | 
| Type of brain lesion in relation to FES success | Derived from available brain imaging | Assessment and analysis of available imaging will be done after completion of the study by the patient, so after week 30, up to week 50 to collect a batch of finished patients. No imaging will be performed because of the study. | 
| Cost-effectiveness of FES | compared to conventional therapy | analysis after study completion, week 30, using the EQ-5D-Y results. | 
| Change in health | EQ-5D-Y Questionnaire, youth version | assessment at every end of a phase: week 12, 18 and 30. |