L10/11: Functional Electrical Stimulation Flashcards
What is the purpose of Functional electrical stimulation (FES)?
Uses ES to produce a functional movement or series of movements
What is ES?
EXAM QUESTION
Any type of electrical stimulation
What is EMS?
EXAM QUESTION
Electrical muscle stimulation to excite denervated muscle directly
What is NMES?
EXAM QUESTION
Neuromuscular electrical stim used to stim a peripheral nerve & to cause a sensory, motor or noxious response
What is TENS?
EXAM QUESTION
Transcutaneous electrical nerve stimulation used as an analgesic without causing muscle contraction
What is TES?
EXAM QUESTION
Therapeutic electrical stimulation causing a muscle contraction which aims to improve impairments after stimulation
What is FES?
EXAM QUESTION
Functional electrical stimulation causing a muscle contraction to assist the performance of function during stimulation
When are 2 scenarios when ES is used?
EXAM QUESTION
- Stimulation of motor nerves (e.g. Stroke)
- Stimulation of denervated muscle (e.g. Spinal cord injury)
What are the 6 uses of FES?
- When individuals do not have ‘enough movement to work with’ – insufficient motor drive to produce an active movement
- Used during physiotherapy treatment / rehabilitation – to facilitate / activate / exercise the muscle (therapeutic)
- Used during everyday life to replace lost function
- Upper and lower limb function
- Bowel and bladder function
- Respiratory functon
What are the 3 types of FES?
- Surface vs. intramuscular
- Single vs. multi-channel
- Applications – manual vs. cyclic vs. triggered vs. controlled
What are 4 characteritics surface FES?
- Most common clinical application
- Non-invasive, low cost
- Easy to apply and remove electrodes
- Electrodes &stimulators available
What are 3 disadvantages of surface FES?
- Pain from stimulation intensity used
- Lack of muscle selectivity- deep muscles & in severe
- Reproducibility affects by accuracy of electrode placement
What is Surface FES similar to?
TENS
Why do you need to draw around the electrodes (on the skin) when using surface FES?
- Usually draw on electrodes
- Able to maintain consistency
- Spend time on first time (good placement)
What are 4 characteristics of intramuscular FES?
- Percutaneous – indwelling wires through the skin
- Fully implanted electrodes and circuits
- Bypass skin and cutaneous sensory fibres so less painful contractions, more efficient, less current
- More selective & sensitive to small EMG signals
What are the 3 disadvantages of intramuscular FES?
- Research applications or research trials
- Invasive – percutaneous or surgical
- Maybe only used in spinal cord injuries -Activate muscles long term
What are the 2 types of channel FES?
- Single
- Multichannel
What is single channel FES?
Single ES to one muscle group for therapeutic use (to exercise / activate)
What is multi-channel FES?
Multi-channel ES to several muscle groups (simultaneous, alternating) for therapeutic use (to exercise / activate
What are 4 applications of FES?
- Manual
- Cyclic
- Triggered
- Controlled
What is the manual application of FES?
operator controlled
What is the cyclic application of FES?
activates paretic muscle at set duty cycle for set time period.
Patent is passive recipient.
What is the triggered application of FES?
stimulation is triggered by an event
What is the controlled application of FES?
ES is controlled by events like initiation, maintenance and termination of a contraction
What are 6 characteristics of manual ES?
- Stimulation controlled by a hand-switch
- Hand switch controls work and rest timing
- Allows timing of muscle contraction to co- incide with activities
- Allows active engagement
- Allows client to control the movement
- Needs someone who understands movement trying to achieve to be present at all times
What is important for the person controlling the machine in manual ES?
Person controlling machine needs to know parameters
What are 3 characteristics of cyclic ES?
- Mild to moderate, chronic paresis
- Single joint movements
- No to minimal cognitive investment
What is the purpose of cyclic ES?
- Prevention of shoulder subluxation
- Muscle activation
- No need to think about it (not consciously comtrolled)
What are 3 outcomes of cyclic ES?
✔ Impairments – ROM, strength
✔ Impairments – Shoulder sublux
X Activity
What is the clinical implication of cyclic ES?
Cyclic ES machines are simple &cheap BUT … need to incorporate into active task oriented practice
What are the 6 types of triggered ES?
- Positional feedback ES
- Pressure-switch triggered ES
- Electromyogram-triggered ES
- Contralateral-triggered ES
- Outcome-triggered ES
- Accelerometer-triggered ES
What are 3 characteristics of positional feedback ES?
- Achievement of a preset degree of wrist extension triggered ES
- Moderate to severe, chronic paresis
- Single joint movements + > cognitive investment & goal setting ? greater potential for motor learning
What is the outcome of positional feedback ES?
Good outcome
What are the clinical implications of the positive feedback ES?
- Research undertaken in 1970’s
- Not commercially available
What are 4 characteristics of pressure-switch triggered ES?
- Pressure switch connected by wires or wireless technology inserted into footwear – must wear footwear
- Allows for timing of stimulation to match gait cycle Allows for augmented muscle activity during weightshift or standing exercises
- Most commonly worn under heel
Where are pressure-switched triggered ES usually worn?
Worn under the heel
Why is pressure-switch triggered ES usually worn under the heel?
Used (bioness) for foot drop
’
Activates TA when heel is up, TA turns off when heel touches the ground
When TA is not working –> chronic problem –> use FES (neuro-prosthesis) C
ompensating = increase energy cost and risk of falling
Circumduction
Bolting (lift hip up higher)
What does EMG-triggered ES look like?
- Detect what is happening at the muscles
- Certain threshold of activity –> stimulate the stimulation to come on –> activity
- Need some activity in target muscle for the EMG (to begin)
What is required from the beginning for EMG-triggered to work?
- cognitive engagement
- some activity in target muscle
- Some activity in the target muscle (otherwise, muscles can’t be activated)
How does EMG-triggered Eswork? List the 4 steps.
- Electrodes placed over target muscle
- Patient voluntarily contracts muscle
- Needs to reach a preset level of activity to then make the stimulation work
- Stimulation then helps to complete full movement
How does automatic adjustment work in EMG-triggered ES?
Automatic adjustment – if patient can’t achieve set level – device automatically reduces threshold – or if does meet it – automatically raises threshold
When is EMG-triggered ES used?
Motor learning based –> retraining motor tasks (eg. reaching)
- Mild, moderate, chronic paresis
- Moderate to severe, acute paresis
- Single joint mulG joint
What are the 2 outcomes of EMG-triggered ES?
- Impairment (wr & fingers) – level 1 - 3RCTs
- AcGvity (UL) (improves activity but no benefit over usual care) – 8 RCTs – mixture severity levels ´
What is contralateral triggered ES?
Unaffected arm triggers delivery of stimulation to affected arm
What are the 5 clinical implications of contralateral triggered ES?
- Not available outside research
- Unimpaired hand is engaged – loss of good hand functionally
- Does it work partly due to bilateral facilitation of movement?
- Synchronous bilateral v asynchronous bilateral task
- Only can do bilateral symmetrical task –> might not be functional
What are 4 characteristics of outcome-triggered ES?
- Moderate to severe, acute paresis
- Multiple and severe impairments
- Multi joint movement
- Combined with an ancillary device
How does outcome-triggered ES work?
Had to reach a certain distance
Why is outcome-triggered ES good?
Sometimes cheating when activating muscle –> reward poor performance (false)