Functional electrical stimulation (FES)

Functional Electrical Stimulation (FES) uses electrical impulses to stimulate muscles that are weak or paralysed. This is done using sticky pads which are placed on the skin over the muscle. It has a very similar set up to a TENS machine. TENS is used to treat pain and FES is used to strengthen muscles.

This is an example of an FES machine that we use at Sheffield Children’s Hospital, but there are many different types.

Can FES help me?

FES can be useful for children with neurological conditions such as:

• acquired brain injury
• stroke
• spinal cord injury (above T12 level)

If your child has a lower nerve injury, for example a lower level spinal cord injury (below T12), FES may not work for them. If you would like more information, please ask your physiotherapist.

Is it safe?

Yes, FES is safe to use for children. We always complete a medical screen before using FES, as there are some conditions where we would not use it.

What are the benefits of using FES?

Benefits of using FES include:

• strengthening weak muscles
• prevention of muscle atrophy
• improved blood flow to the area
• sensory stimulation

Are there any precautions?

Yes, FES would not be used with:

• an unstable fracture (broken bone)
• a medical implant such as a pacemaker or Vagal Nerve Stimulator (VNS)
• in pregnancy

We are cautious using FES if you have:

• broken, sensitive or fragile skin
• epilepsy
• cancer
• autonomic dysreflexia (a problem that can happen after a spinal cord injury)
• medical devices such as a baclofen pump
• metal work such as orthopaedic plates and screws

Are there any side effects?

The most common side effect is reaction to the sticky pads where the skin may be red underneath after using. This should fade within 20 minutes. To avoid this, we recommend building up time using FES slowly and changing the pads once they start to lose their stickiness, which tends to happen after about a month of regular use.

What does it feel like?

Many children describe the feeling under the pads as tickly, buzzy, or like pins and needles. It should not feel painful and we increased the intensity slowly. Stop if there is any discomfort. If you have any problems with sensation, you may not feel anything. The machine is battery powered, meaning it uses the same power source as your remote control.

As you turn up the settings, you may see flickers of activity in the muscle, your muscle contracting, or see movement around a joint.

How often should I use it?

The evidence tells us that FES should be used 3 times a week minimum, for around 6 weeks to see the best results. You can use it more, but you will need to build up the time slowly to avoid irritating the skin, or tiring out your muscles.

How do I use it?

Your physiotherapist or occupational therapist will review which muscles to stimulate and show you where to place the pads. They will find the correct settings for you. You may want to take a picture of the pads to help you remember where to place them. Attach the sticky pads to the machine using the wires and remember which channel leads to which muscle. The leads have a black and red end. We recommend attaching the black end to the pad closest to the spine.

The power button has a green circle around it in the image above. The screen will light up blue when switched on.

The arrow pointing up circled in red starts to increase the strength of electrical impulse. It is this button that will allow you to control the intensity (how strong you want the impulses to be). The number also circled red tells you the intensity and goes from 0 to 100.

You can see there are 4 channels (CH1, CH2, CH3, CH4). Each channel has its own up and down arrow so you can have different intensities on different muscles.

There is a light where the orange square is on the picture. When the light comes on the impulse is on the machine is sending impulses and be off when it is not. Your therapist will set the timing and can adjust it for you.

Your therapist will enter the settings to use and then you can start to gently increase the power until you start to feel a sensation (like the buzzy or tickly feeling). Start at 5, pressing the button in red and increase slowly (normally by 2 or 3 each time). We call this the sensory level, where you can feel the stimulation. Most children find their sensory level is around 5 to 15, but it can be much higher. Note down this number.

Slowly increase the power until you can start to see or feel flickers of movement or the muscle contracting. We call this the motor level. Note down this number. The motor level can vary but you may start noticing flickers as low as 15. These numbers will help you start at the right place you know is comfortable the next time you use the machine.

Sensory level:

Motor level:

Once you have found the right settings, your therapist can show you how to use FES as part of your therapy programme or home exercise programme.

Can I take the machine home when I leave hospital?

Unfortunately you cannot take the machine home with you, as we do not currently have an outpatient FES service. Speak to your therapist about funding options, or purchasing an FES machine.

If you have any questions or need more information about FES, please call the Neuro-oncology therapy team office on 0114 226 0646.