Functional Electrical Stimulation-Assisted Walking: Enhancement of Voluntary Walking Function Among Persons with Severe Hemiplegia Post Stroke

Transcription

1 Functional Electrical Stimulation-Assisted Walking: Enhancement of Voluntary Walking Function Among Persons with Severe Hemiplegia Post Stroke Naaz Kapadia Date: May 10, 2010 Research Coordinator-Physiotherapist Toronto Rehabilitation Institute Lyndhurst Centre

2 Background Stroke is a leading cause of death and disability throughout the developed world [1,2]. According to the Heart and Stroke Foundation of Canada, between 40,000 and 50,000 Canadians suffer a stroke each year. According to Mayo et al. [3] 85% of individuals who have had a stroke do not reach their age-specific norms for gait speed 3 months after stroke and 40% do not recover any walking function at all. Functional electrical stimulation (FES) is currently the most promising approach to promote recovery of walking function in people with severe hemiparesis. It was first developed in 1961 as a means to correct drop-foot, a common condition resulting from stroke in which the foot drops down from its own weight and the muscles spanning the ankle are unable to lift it [4].

3 Background (contd.) FES walking systems for stroke can be divided into two categories: 1) Drop-foot stimulators, and 2) multi-channel stimulators. Recently it was established that single-channel FES (mainly used to stimulate dorsi flexors) combined with conventional therapy was not superior to conventional therapy alone, suggesting that single channel, drop-foot FES system has little added benefit to therapy [5]. Bogataj et al. [6] in 1995 presented one of the most promising reports of the efficacy of multi-channel stimulation in restoration of voluntary walking ability in severe stroke. They provided preliminary evidence that non-ambulatory patients improved to a greater extent following 3-weeks of multi-channel FES than following conventional physiotherapy, as measured by Fugl-Meyer scale. Longer duration intervention studies that include a follow-up period are warranted.

4 Objectives The primary objective of the proposed pilot randomized controlled trial (RCT) is to explore whether an FES-assisted walking intervention can stimulate or improve walking ability in individuals with severe lower extremity paresis secondary to hemiplegic stroke. The secondary objectives of the study are to explore whether the FES-assisted walking intervention has a positive impact on balance, activities of daily living, and whole body and leg lean mass in the same patient population.

5 Rationale for the pilot RCT To date there is no precedent to FES-assisted walking therapy in individuals with severe stroke. The purpose of this pilot RCT with stratification (non ambulators and home ambulators) by ambulatory status is to establish whether a larger RCT of FES-assisted walking therapy in individuals with severe stroke is warranted. To determine whether it is necessary to target individuals with some walking ability at baseline (as has been done in the past with other FES therapies), and to determine if other outcomes (e.g. balance, muscle mass) can be improved besides improvements in walking ability with FES. In addition, this study should help us determine appropriate recruitment rates, adherence rates, and whether or not the selected primary and secondary outcome measures are appropriate for the prospective larger RCT.

6 Study population and Inclusion/Exclusion Criteria Sample size: 40 Basic Inclusion Criteria: * Individuals 65 years or older * Individuals who have suffered cortical or sub-cortical hemiplegia in the motor cortex area, which resulted in severe unilateral lower extremity paralysis. * Individuals who are at least 12 months post stroke prior to joining the study. More stringent inclusion/exclusion criteria will be applied at the time of on site screening assessments. Individuals who agree to participate will be stratified by ambulation status into two categories prior to randomization i.e. Non ambulators or home ambulators.

7 Outcome Measures 2 min walk test Functional Ambulatory Category Time taken to perform sit to stand transition Berg Balance Scale Spatial and Temporal Parameters of balance derived during quite standing on the Force plates. Activities-specific Balance Confidence (ABC) Scale. Whole Body and Leg Lean Mass Leg and Foot Components of the Chedoke-McMaster Stroke Assessment Scale (CMSAS) Functional Independence Measure

8 Screening Assessment Visits Telephone screening Onsite screening assessment 1 *Informed consent *Medical history and chart review *ECG *2 min walk test and TUG *FES screening Onsite screening assessment 2 *Cardiac screening by a Cardiologist If all inclusion/exclusion criteria are met then Baseline assessments commence.

9 Baseline and Follow up assessments The baseline assessments will be completed over two visits. The assessments will include analysis of all outcome measures. Upon completion of the assessment, participants will be randomized to intervention or control group, stratified by ambulation category so that there are 10 individuals from each ambulation category (i.e., nonambulators and home-ambulators) in each group. Participants will be randomized using a computergenerated randomization schedule. Participants will be re-assessed on all outcome measures upon completion of the 8-week intervention, and at a follow-up visit 6 months after the baseline visit.

10 Treatment protocol for the intervention group Licensed physiotherapists will administer the therapy 45 minutes daily, 3 days per week for 8 weeks. A patient specific FES walking protocol will be developed for the participant using fully programmable transcutaneous (surface) electrical stimulation system, Compex Motion [7]. Once the number of stimulation electrodes, their placement and the stimulation patterns are chosen the patient will be invited to participate in the first FESassisted walking session. The stimulation electrodes will be placed on the participant s skin at the motor points above the nerves corresponding to the muscles that will be targeted with FES.

11 Electrode placement during therapy

12 Treatment protocol for the intervention group (contd.) Stimulus signals will be balanced, biphasic, and pulsewidth modulated with constant current regulation. Pulse amplitudes from 8 to 125 ma will be used (subject and muscle dependent), and pulse-widths will vary from 0 to 300 µs. Pulse frequencies from 20 to 50 Hz will be used. The Compex Motion stimulator will provide open-loop stimulation sequences triggered by a pushbutton, which will be pressed by a therapist to initiate each step. Walking exercises will be performed on a treadmill Loko 70 (Woodway, USA) to ensure safety of the participants during therapy.

13 Treatment protocol for the intervention group (contd.) The Loko 70 includes an overhead harness that attaches to cables and pulleys. The harness will be used only as a safety mechanism to prevent injury in the case a patient looses balance during FES-assisted walking therapy. The participants will use the treadmill hand rails to maintain balance during walking. Walking exercises will be performed at the following speeds: a) as tolerated for non-ambulators and b) preferred/comfortable walking speed plus 20% for home-ambulators. Manual assistance will be applied when needed to the participant s lower extremities and lower back to facilitate proper gait.

14 Treatment protocol for the control Two physiotherapists will administer the therapy 45 minutes daily, 3 days per week for 8 weeks The placebo FES protocol will be the same as the FES protocol used with the intervention group, except that the stimulation levels will be sub-threshold levels, i.e. the stimulation will not generate muscle contractions and the muscle stimulation pattern will not have any bearing on the muscle activation required during gait.

15 Statistical Analysis The results of participant demographics and medical history and all outcome assessments will be summarized using descriptive summary measures: expressed as mean (standard deviation) or median (minimum-maximum) for continuous variables; and number (percent) for categorical variables. Linear regression models will be used for continuous outcome measures. For all models, we will report the odds ratios (for logistic regression) or coefficient (for linear regression), corresponding standard error, 95% confidence intervals and associated p-values. We will report p-values to 3 decimal places with p-values less than reported as p< For all tests, we will use alpha = 0.05 level of significance.

16 Projected results We are anticipating that improvements on all outcomes will be significantly higher in the FES group, and there will be an ambulatory status x FES/control interaction. There will be at least a 30% improvement in walking speed on a 2 min walk test in home ambulators post therapy compared to baseline. The non ambulators will be able to walk a distance greater than 10 mts in 25 seconds achieving a minimum speed of 0.4m/s during a two-minute walking test.

17 References 1. Hesse S., Rehabilitation of gait after stroke: evaluation, principles of therapy, novel treatment approaches, and assistive devices, Topics in Geriatric Rehabilitation 2003;19(2): Johansen H.L., Wielgosz A.T., Nguyen K., and Fry R.N.. Incidence, comorbidity, case fatality and readmission of hospitalized stroke patients in Canada, Canadian Journal of Cardiology. 2006;22(1): Mayo N.E., Wood-Dauphinee S., Ahmed S., Gordon C., Higgins J., McEwen S., and Salbach N., Disablement following stroke, Disability and Rehabilitation, 1999;21: Liberson W.T., Holmquest H.J., Scot D., and Dow M., Functional electrotherapy: Stimulation of the peroneal nerve synchronized with the swing phase of the gait of hemiplegic patients, Archives of Physical Medicine and Rehabilitation. 1961;42: Daly J.J., Kollar K., Debogorski A., Strasshofer B., Marsolais E.B., Scheiner A. et al. Performance of an intramuscular electrode during functional neuromuscular stimulation for gait training post stroke, Journal of Rehabilitation Research and Development 2001;38(5):

18 References (contd.) 6. Bogataj U., Gros N., Kljajic M., Acimovic R., and Malezic M., The rehabilitation of gait in patients with hemiplegia: A comparison between conventional therapy and multichannel functional electrical stimulation therapy, Physical Therapy 1995;75(6): Popovic M.R. and Keller T., Modular transcutaneous functional electrical stimulation system, Medical Engineering and Physics.2005; 27(1): TRI Council Policy Statement concerning Ethical Conduct for Research Involving Humans, published by Canadian Institutes of Health Research, Daly J.J., Roenigk K., Holcomb J., Rogers J.M., Butler K., Gansen J., McCabe J., Fredrickson E., Marsolais E.B., and Ruff R.L.A., A randomized controlled trial of functional neuromuscular stimulation in chronic stroke subjects, Stroke, 2006;37(1): Dobkin, B.H., Rehabilitation after stroke, The New England Journal of Medicine, (16):

19 References (contd.) 11. The Glasgow Augmented Physiotherapy Study Group, Can augmented physiotherapy input enhance recovery of mobility after stroke? A randomized controlled trial, Clinical Rehabilitation, (5): Yan T., Hui-Chan C.W., and Li L.S., Functional electrical stimulation improves motor recovery of the lower extremity and walking ability of subjects with first acute stroke: a randomized placebo-controlled trial, Stroke, (1): Popovic M.R., Thrasher T.A., Zivanovic V., Takaki J., and Hajek V., Neuroprosthesis for restoring reaching and grasping functions in severe hemiplegic patients, Neuromodulation (1): Popovic, M.R. and Thrasher, T.A. Neuroprostheses, in Encyclopedia of Biomaterials and Biomedical Engineering, G.E. Wnek and G.L. Bowlin, Eds.: Marcel Dekker, Inc., : Thrasher T.A., Flett H.M., and Popovic M.R., Gait training regimen for incomplete spinal cord injury using functional electrical stimulation, Accepted for publishing in Spinal Cord in August Popovic M.R., Thrasher T.A., Adams M.E., Takes V., Zivanovic V., and Tonack M.I., Functional electrical therapy: Retraining grasping in spinal cord injury, Spinal Cord, (3):

20 Thank you