Hemiplegia
Conditions
Keywords
Electric Stimulation, Hemiplegia, walking
Brief summary
The purpose of this research is to find the optimal patterns of functional electrical stimulation (FES) of muscles in the lower legs that will improve walking ability in those who have had a stroke and at the same time ensure walking stability. FES involves applying small electric currents to the nerves, which cause the muscles to contract. FES research projects vary from simple investigations of the therapeutic effects of exercise on muscle function and skin health, to more complex studies of functional movements such as standing or walking.
Detailed description
The study aims to find the optimal patterns of functional electrical stimulation (FES) of muscles in the lower legs that will improve walking ability in those who have had a stroke and at the same time ensure walking stability will be achieved through an analytical approach comprised of computational models and gait simulations to objectively determine patient-specific patterns of muscle activation. The investigators will develop a computer simulation of the dynamics of hemiplegic gait characterized by unilateral plantarflexor weakness. Then, the investigators will relate the results of the computer model results to real data collected from subjects with known plantarflexor weakness to provide a theoretical basis for improving gait efficiency and stability with FES.
Interventions
DEVICEFES
Surface stimulation to contract the muscles in the lower extremity
Sponsors
VA Office of Research and Development
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
This study includes stroke survivors greater than 18 years of age, \>180 days from first clinical hemorrhagic or nonhemorrhagic stroke with: * Unilateral hemiparesis with sufficient endurance and motor ability to ambulate \>30 feet continuously without an AFO requiring no more than 25% physical help * Berg Balance Scale score \>23 without assistive devices * Standing ankle dorsiflexion strength of \<4/5 * Foot-drop during ambulation with gait instability or inefficient gait defined as supervision need * Possible use of physical assistance or assistive device (cane, walker) * Evidence of foot-drop as seen by dragging or catching of affected toes during limb swing or circumducting affected limb * Vaulting of the unaffected limb or hiking the affected hip to clear toes. * Intact and electrically ex-citable lower motor neurons * Ankle dorsiflexion to at least neutral while standing with electrical stimulation of common peroneal and tibial nerves without painful hypersensitivity to stimulation * Adequate social support and stability * Medically stable with intact skin in affected lower limb * Willingness to comply during research procedures * No systemic co-morbidities * No history of potentially fatal cardiac arrhythmias i.e. ventricular tachycardia, supraventricular tachycardia and rapid ventricular response atrial fibrillation with hemodynamic instability * No psychological problems or chemical dependency * No acute medical complications such as depression or chronic anxiety requiring long term pharmacological therapy. Able-bodied controls must be of similar age, body mass and stature as those with hemiparesis and must be free of any medical and disabling orthopedic problems.
Exclusion criteria
In addition to failure to meet the inclusion criteria, participants will be excluded from the study for the following: * Requires an ankle foot orthosis (AFO) to prevent knee flexion collapse in stance * Excessive edema of affected extremity * Absent sensation in affected limb * History of potentially fatal cardiac arrhythmias such as ventricular tachycardia, supraventricular tachycardia, and rapid ventricular response, atrial fibrillation with hemodynamic instability * Demand pacemakers or any implanted electronic systems * Pregnancy * Uncontrolled seizure disorder * Ipsilateral lower limb lower motor neuron lesion * Parkinson's disease * Spinal cord injury * Traumatic brain injury * Multiple sclerosis * Ankle plantar flexor contraction * Severely impaired cognition and communication * Painful hypersensitivity to neuromuscular stimulation of common peroneal nerve * Knee hyperextension (genu recurvatum) that cannot be adequately corrected with peroneal nerve stimulation * History of botulinum toxin to the lower extremity within the prior three months.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Walking Stability and Speed | pre-stimulation (volitional) and post-stimulation (FES), day of the study | This was a feasibility study of computational models and gait simulations to objectively determine patient-specific patterns of muscle activation. We developed computer models and walking simulations of hemiplegic gait from 8 subjects. We related the model results (muscle activations) to the optimized data collected from hemiplegic subjects & calculated the FES pattern to be delivered in 2 forms (open loop & foot switch triggered). The primary outcome measure turned out to be the feasibility of the methods because after developing our computer modeling and computational optimization framework we could only test walking with the 2 forms of FES at the same preferred walking speed on a treadmill. Thus, the simulated walking speed and the real walking speed pre and post FES turned out to be the same. Walking stability was measured with variability in work performed at the ankle. The additional volitional and FES biomechanical data that were measured are listed in the secondary measures. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Peak Ankle Power | Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study | This is the peak ankle power during walking normalized by body weight. |
| Positive Ankle Work | Same day; pre-stimulation (volitional) and post-stimulation (FES), day of the study | This is the amount of positive work performed by the ankle during walking normalized by body mass. |
| The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. | Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study | The is the magnitude of ground reaction force over time per step in the anterior direction during walking. |
Countries
United States
Participant flow
Pre-assignment details
Computational optimization was via tracking joint angles & ground reaction forces from an able walking subject.We optimized the hemiparetic (HP) subject's model to able data & their walking data producing optimization solutions for muscle activations in each case.The able subject was not considered enrolled,only 9 HPsubjects were actually enrolled.
Participants by arm
| Arm | Count |
|---|---|
| Arm 1: FES Case-control study: pre- and post-stimulation (FES).
FES: Surface stimulation to contract the muscles in the lower extremity where subjects serve as their own control. | 8 |
| Total | 8 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | One participant did not respond to FES. | 1 |
Baseline characteristics
| Characteristic | Arm 1: FES | — |
|---|---|---|
| Age, Categorical <=18 years | 0 Participants | — |
| Age, Categorical >=65 years | 6 Participants | — |
| Age, Categorical Between 18 and 65 years | 2 Participants | — |
| Age, Continuous | 64.1 years STANDARD_DEVIATION 14 | — |
| Race and Ethnicity Not Collected | — | — Participants |
| Region of Enrollment United States | 8 Participants | — |
| Sex: Female, Male Female | 2 Participants | — |
| Sex: Female, Male Male | 6 Participants | — |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 9 |
| serious Total, serious adverse events | 0 / 9 |
Outcome results
Primary
Walking Stability and Speed
This was a feasibility study of computational models and gait simulations to objectively determine patient-specific patterns of muscle activation. We developed computer models and walking simulations of hemiplegic gait from 8 subjects. We related the model results (muscle activations) to the optimized data collected from hemiplegic subjects & calculated the FES pattern to be delivered in 2 forms (open loop & foot switch triggered). The primary outcome measure turned out to be the feasibility of the methods because after developing our computer modeling and computational optimization framework we could only test walking with the 2 forms of FES at the same preferred walking speed on a treadmill. Thus, the simulated walking speed and the real walking speed pre and post FES turned out to be the same. Walking stability was measured with variability in work performed at the ankle. The additional volitional and FES biomechanical data that were measured are listed in the secondary measures.
Time frame: pre-stimulation (volitional) and post-stimulation (FES), day of the study
Population: Volitional and FES data available for participants with hemiparesis.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Arm 1: FES | Walking Stability and Speed | Volitional | 0.1055 Joules/body mass in kilograms | Standard Deviation 0.0117 |
| Arm 1: FES | Walking Stability and Speed | FES: Open loop | 0.0390 Joules/body mass in kilograms | Standard Deviation 0.0716 |
| Arm 1: FES | Walking Stability and Speed | FES: Foot switch Trigger | 0.0206 Joules/body mass in kilograms | Standard Deviation 0.0209 |
Secondary
Peak Ankle Power
This is the peak ankle power during walking normalized by body weight.
Time frame: Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study
Population: Volitional and FES data available for participants with hemiparesis.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Arm 1: FES | Peak Ankle Power | Volitional | 0.9162 Watts/body mass in kilograms | Standard Deviation 1.0242 |
| Arm 1: FES | Peak Ankle Power | FES: Open Loop | 1.1392 Watts/body mass in kilograms | Standard Deviation 1.1438 |
| Arm 1: FES | Peak Ankle Power | FES: Foot switch Trigger | 0.6315 Watts/body mass in kilograms | Standard Deviation 0.6106 |
Secondary
Positive Ankle Work
This is the amount of positive work performed by the ankle during walking normalized by body mass.
Time frame: Same day; pre-stimulation (volitional) and post-stimulation (FES), day of the study
Population: Volitional and FES data available for participants with hemiparesis.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Arm 1: FES | Positive Ankle Work | Volitional | 0.1097 Joules/body mass in kilograms | Standard Deviation 0.0909 |
| Arm 1: FES | Positive Ankle Work | FES: Open loop | 0.1423 Joules/body mass in kilograms | Standard Deviation 0.1122 |
| Arm 1: FES | Positive Ankle Work | FES: Foot switch Trigger | 0.0869 Joules/body mass in kilograms | Standard Deviation 0.0447 |
Secondary
The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass.
The is the magnitude of ground reaction force over time per step in the anterior direction during walking.
Time frame: Same day: pre-stimulation (volitional) and post-stimulation (FES), day of the study
Population: Volitional and FES data available for participants with hemiparesis.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Arm 1: FES | The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. | Volitional | 0.0100 Newtons*seconds/body mass in kilograms | Standard Deviation 0.0081 |
| Arm 1: FES | The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. | FES: Open loop | 0.0106 Newtons*seconds/body mass in kilograms | Standard Deviation 0.0081 |
| Arm 1: FES | The Impulse of the Anterior Ground Reaction Force Normalized by Body Mass. | FES: Foot switch Trigger | 0.0109 Newtons*seconds/body mass in kilograms | Standard Deviation 0.0102 |