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Functional Electrical Stimulation (FES) - a re-emerging technology. Ian Swain Dept. of Medical Physics and Biomedical Engineering, Salisbury District Hospital, U.K. Academic Biomedical Engineering Research Group, Bournemouth University, U.K.
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Functional Electrical Stimulation (FES) - a re-emerging technology Ian Swain Dept. of Medical Physics and Biomedical Engineering, Salisbury District Hospital, U.K. Academic Biomedical Engineering Research Group, Bournemouth University, U.K.
What are the Prerequisites for a Clinical FES Service • Clinical demand • Evidence that the technique works • Management, Consultant, GP/PCT and patient support - all ideally needed • Adequate and reliable funding • Information • Reliable equipment • Trained staff
118,000 new strokes per year in UK, 10,000 under 50 1,000 under 30 80% survival, 30% complete recovery about 10,000 left with dropped foot 85,000 MS in UK CP Head injury Incomplete Spinal cord injury Demand
Evidence -Randomised controlled trial of the Odstock Dropped Foot Stimulator Jane Burridge, Paul Taylor, Ian Swain Salisbury District Hospital
Study • 32 subjects who had had a Stroke randomly allocated to an FES and a control group • Each group received 10 one hour sessions of physiotherapy over 1 month. The FES group used the stimulator in the sessions and at home • Assessments at start, 1 month and three months
Assessments • Walking speed • Physiological Cost Index (PCI) • Spasticity - Watenberg pendulum drop test • Mobility questionnaire • Nothingham QoL Health profile • Hospital Anxiety and Depression index • Use of stimulator questionnaire
Walking speed at 3 months • With stimulation 20.5% p < 0.01 • No Stimulation 0.12% p = 1 • Control 5.2% p = 0.38
PCI at 3 months • With Stimulation -24.1% p < 0.01 • No stimulation -11.8% p = 0.67 • Controls -3.9 % p = 0.47
Quadriceps Spasticity • A reduction in spasticity seen in the control group after 10 sessions of physiotherapy. This was lost after 2 months • A reduction in spasticity in the FES group at the third assessment
Treatment Group Depression 5.5 3.5 p = 0.0028 Anxiety 5.3 3.0 p = 0.0047 Control Group Depression 4.3 3.8 p = 0.441 Anxiety 4.8 3.7 p = 0.096 Hospital Anxiety and Depression Index (HAD)
Conclusions • Significant increase in walking speed in FES group - no change in control group • Significant fall in PCI in FES group - no change in the control group • Reduction in spasticity in FES group only • Reduced HAD score • Positive cost-benefit (QALY gain of 0.042)
Patients treated in Salisbury (7/04/05) • Service running for eleven years • Over 2000 patients referred to the service and seen, not including the many who have participated in clinical trials • 880 CVA, 540 MS, 120 SCI, 63 CP, 25 facial, 31 TBI, plus other neurological conditions
Reliable equipment • MUST meet patients needs • User involvement essential to design process • large numbers needed to trial, then modify design accordingly, iterative process • RELIABLE • ODFS footswitch works every time, fifteen years development ~1-200,000 cycles, ~6/12 use • Safe, and built to recognised standards • Quality control, e.g. ISO 9000 • CE marked
Equipment Currently Available • Few practical systems available such as the FreeHand, HandMaster, Vocair (Brindley Bladder Stimulator), ODFS etc • From Salisbury we can supply (to registered users) • ODFS • 2 channel ODFS • 2 and 4 channel exercise stimulators • consumables • implanted dropped foot system - STIM-U-STEP
Stim-U-Step • 2 channel implanted stimulator • CE marked, clinical service later this year • Deep branch • dorsiflexion + inversion • Superficial branch • dorsiflexion + eversion • Developed with EU funding with, Salford, Het Roessingh and Finetech
Staff Training • FES equipment has a tendency to be sold from back pages of newspapers • FES is not a treatment in itself it is a part of a rehabilitation programme • use with BoTox, orthotics, therapy etc • Only trained staff can order and fit equipment. • Therefore continuous training, education and support needed
Patient Support • Clinical guidelines/ Care pathways • 82%success at initial assessment • Prompt repair service • Ongoing support for staff and patients • 86%compliance at 1 year • Audit and regular questionnaires
Stroke Use every day 48% Use 4-6 days 15% 10 to 100 yds 38% 100 to 500 yds 33% 500 yds to 1 m 12% 1 m + 8% MS Use every day 40% Use 4-6 days 28% 10 to 100 yds* 40% 100 to 500 yds** 38% 500 yds to 1 m 8% 1 m + 5% *EDSS 6 - 6.5 **EDSS 4 - 5.5 How is the ODFS used?
Stroke Less effort 27% Long term hope 20% Carryover 22% More confident 10% MS Less effort 33% Trip less 28% Walk further 10% More confident 10% No stick 10% Most important reason
Clinical Treatment Stroke • very good 85% • good 12% MS • very good 75% • good 25%
Exercises • Reciprocal flexion and extension of the wrist and fingers, optionally with the lumbrical muscles. • Exercises began at two periods of 15 minutes a day, increasing to two periods of 1 hour by three months • 20 Hz, 300 micro Seconds, up to 80 mA.
Measurements • 1. The Jebsen-Taylor hand function test. • 2. Static two point discrimination • 3. Power, pinch and key grip strength
JEBSEN-TAYLOR % CHANGE 200 150 100 %CHANGE % CHANGE 50 0 1 3 5 7 9 11 13 15 17 19 -50 SUBJECTS
Conclusions • 1. There are statistically significant improvements in static two point discrimination score, Jebsen-Taylor test score and key grip strength following three months of electrical stimulation exercises. • 2. It is not clear if there are significant benefits in ADL, though some anecdotal evidence was reported. • 3. There is evidence to support the use of FES in shoulder subluxation (Chae,J) and useful in improving hygiene in severe spasticity.
Clinical Service 1 • Dropped foot correction • Bilateral dropped foot • More complex movement problems • 2 channel stimulator • in conjunction with orthotics • Upper limb function • Facial stimulation • Orthopaedic
Clinical Service 2 (07/04/05) • In Salisbury - • up to 6 new patients per week, usually 4 • 42 follow up sessions per week • 1180 ODFS users, 266 2 Channel, over 350 upper limb & over 350 lower limb exercise • At present new patients are approx. 50%NHS and 50% private
Clinical Service 3 • Set up: • 2 consecutive days • each session 1 to 1 1/2 hours • Follow up 6 weeks later • Then 3 months later • Then 6 months later • Then yearly for as long as the system is used.
Clinical Service 4 • ISO 9000 system in place • Rapid assistance if experiencing problems • Rapid repair service • Telephone advice • User questionnaire/ comment book
Advantages of running a clinical service for a research centre • Increases clinical experience • Ensures research is to the advantage of patients • Improves recruitment for trials • Constantly raises new areas of research • Completes the design process, iterative • What’s the point without it.
Advantages of running a purely clinical FES centre • Better treatment for patient • Evidence based treatment • Ongoing treatment for a group of patients who often feel neglected • chronic CVA, MS, TBI etc • Service well liked by patients
Disadvantages of running a clinical FES centre • Long term commitment to patients, often many years • Problems with new, untrained staff coming into the service • Ever increasing patient numbers • Time
Conclusions (7/04/05) • In Salisbury we have seen over 2000 patients • over twelve years longest usage • results improve to 41/2 months then constant • estimated UK prevelence 75,000 incidence 6000 • ODFS recognised by DEC and RCP and RSCG • over 90 courses run, 940+ staff trained • Equipment production, ISO 9000, CE marking • 2370 ODFS sold • sold stimulators to 175 centres to date, £1m income
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