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Functional electrical stimulation or FES is a treatment that is used to produce movement in a muscle that is weak or paralysed. FES uses small electrical impulses to activate nerves supplying the weakened muscles producing a contraction. The muscle contraction is controlled to facilitate a functional movement, for example lifting the foot whilst walking. Electrical activity is produced by a small battery powered electronic device that supplies impulses to electrodes, which are attached on or under the skin. The electrical stimulation device is usually worn on the leg or waist.
Surface or External FES
With surface FES the electrodes are placed over the skin on the required muscles and nerves. Surface electrodes are self-adhesive sticky pads which attach easily to the skin. There are several different types of surface electrodes depending on what is best for you and your comfort, hypoallergenic pads are used if you have sensitive skin. The self-adhesive pads are easy to use, can be reused a number of times and do not involve any invasive procedures.
Implanted or Internal FES
With internal FES surgery is involved to place the electrodes directly onto the nerve. Internal FES fixes the electrodes in place therefore you do not need to worry about the placement of electrodes. The FES activity is controlled wirelessly outside of the body through the FES device. This is usually tested with an external FES device first to ensure suitability.
Surface electrodes are more commonly used in FES treatment than implanted electrodes. You and your therapist can discuss what option may be most suitable for you during the assessment.
Functional electrical stimulation (FES) is used for conditions that affect the brain and spinal cord, for example:
Functional electrical stimulation (FES) is used as a method to strengthen but also re-educate certain muscles. It can be used on most muscles but is commonly used in the legs and foot or in the hand, arm or shoulde
The most common use of FES is for the correction of dropped foot. This is the inability to lift the foot while walking due to weakness or over activity in the calf muscles. FES activates the correct muscles resulting in foot clearance when walking. Having the ability to clear the floor successfully with the help of an FES device can assist in decreasing falls and improving confidence.
Before being fitted with a functional electrical stimulation (FES) device a full assessment will be carried out with one of our specialists, to ensure your suitability for FES. The assessment will firstly involve finding out more about your goals, what you want to achieve with FES and ensuring your understanding of how it works.
A physical assessment will then be completed. This will involve assessing your muscles, movement and will include functional tasks such as walking or gripping. Following this an FES will be fitted and trialled. The user will experience a 'pins and needles' sensation when the current is applied. However, most people become accustomed to it quickly.
You will be required to have a number of follow up appointments following the initial assessment and fitting. The first follow up appointment is usually after one week of using the FES device, following this there will also be regular reviews. This is to assess how you are finding the treatment, ensure you are using the FES device correctly and to make any adjustments that may be required.
The functional electrical stimulation (FES) device will be set up by your therapists to ensure the appropriate and most beneficial settings are implemented.
It is important each time the electrodes are used that they are placed in the correct position to ensure the appropriate movement is produced. Therefore, a good understanding of where the electrodes need to be placed is required by you or a carer. There are a number of methods that can be used to ensure the accuracy of electrode placement such as photographs or written guidelines.
FES primarily works as a long term orthosis for example preventing foot drop whilst walking. During walking the FES device is activated by a pressure sensor placed in the heel of your shoe. An impulse is applied when the heel is lifted causing the foot to lift into the correct position required for walking and preventing foot drop. As the foot is placed back on the ground, pressure is reapplied to the switch and the impulse stops.
The FES device can also be used as a warm up or an exercise programme. Settings can be changed to enable therapeutic training, increasing the benefits of the device and improving function in the muscles.
The FES device can be used every day.
As electrical stimulation is first applied you may feel a 'pins and needles' sensation on your skin. For most people this is not a problem and they will get used to the effect, however some may find the effect uncomfortable. A change in settings such as a reduction in intensity may help to reduce any discomfort.
Occasionally, people find that the stimulation or the electrodes cause irritation of the skin. This can be reduced by changing the type of stimulation used or by using hypoallergenic electrodes.
There are many benefits to using functional electrical stimulation (FES), these include:
Allowing people to stand or walk successfully
During standing a number of muscles are required to keep you up in an upright position. When these muscles are weak or not working correctly there is increased difficulty to stand and maintain position. FES stimulates the weakened muscles to help generate enough activity when standing. The FES machine therefore results in you being able to stand for longer with less fatigue.
Improved function whilst walking
The most common problem that people face whilst walking is foot drop. This is the inability to lift the foot up during walking, which can lead to falls. An FES machine can be placed on certain muscles in the legs to prevent foot drop from occurring. Research suggests that FES for foot drop can help to increase a person's walking speed, distance and reduce the number of falls that occur.
Improved venous return from lower limbs
Venous return is the blood pumping back to the heart from your legs. If your muscles in your legs are weakened or not working effectively blood will not pump as efficiently back to your heart. The FES machine can be set up as an exercise programme which will involve movement of the joints and muscles. This movement of the muscles and joints encourages the blood to pump back to the heart, improving circulation in you lower limbs and preventing any complications from occurring.
Restoring hand and upper limb function
FES can be used to strengthen hand and forearm muscles and enable increased function in these muscles. Muscles in the arm can be stimulated in a coordinated way to help with the ability to grasp, hold and release objects. FES electrodes can also be placed on muscles around the shoulder. This is commonly used for shoulder subluxation which tends to be a result of low tone. The FES machine will stimulate muscle activity around the shoulder, providing more support and stability and resulting in increased function of the whole arm.
FES can be used not only to improve function, but also as a way of reducing spasticity during a functional task. This is often done by stimulating the opposite muscle. Spasticity has been shown to reduce even after the time of stimulation. These carry over effects of reduction in spasticity can be useful in further treatment or for example in improving gait.
Improved strength and range of movement
The FES machine can be placed in an exercise mode. This involves a muscle group being stimulated to cause a contraction. This contraction is repeated a number of times over a set period. The repetitive nature of the exercise setting strengthens the pathways from your brain to your muscle and eventual helps to increase strength and movement in the muscles.
This repetitive nature of the FES machine also helps to improve range of movement by producing regular stretching in the muscles.
All of the above benefits can result in long term therapeutic effects. They can further enhance independence, confidence and result in an improved quality of life.