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This is a routine test performed in specialist hospitals.
The EMG (electromyography) records the electrical messages that muscles produce. The nerve conduction test measures the speed at which the messages travel along a nerve. These tests help us to work out how well your child’s nerves and muscles are working. Together they are often called an EMG test and may include one or both of the above techniques.
EMG stands for electromyography.
Your appointment with the consultant will last about an hour. Whilst we try to keep to appointment times, very occasionally there can be a delay.
Nerve conduction tests record how fast nerves send messages to the brain and back. We send messages to the nerves using pads or rings placed on the surface of your child’s skin. We can then record how fast the message travels to another point where it is recorded using pads placed on the skin. This tells us how fast the nerve is working.
This studies the electrical activity in the muscles. The EMG is recorded using a fine needle electrode inserted into the muscle, which produces a short pinprick sensation. Younger children are offered the option to attend early so that anaesthetic cream may be applied. We also have a coolant spray which may be used to numb the area during the test. Once the needle is in place the activity in the muscle can be observed at rest and then whilst being used.
During the nerve conduction test we send messages to the nerves and they will feel a tapping/tingling sensation. Most children do not find this too uncomfortable. Staff are experienced in comforting anxious children and children with sensory or special needs.
If your child has any implanted electronic device such as cardiac pacemaker, vagal nerve stimulator, then please tell us when you ring in to make their appointment. They can still have the test but we need to modify the position of the electrodes slightly. You must also tell us if they are currently taking anticoagulant (blood thinning) treatment for example, Warfarin tablets. They can still have the nerve conduction part of the test but we may not perform the EMG.
The measurements we take help us to find out whether your child has any trapped or damaged nerves. It can also investigate a wide range of nerve and muscle disorders. The results from the tests can help your child’s consultant to provide the right treatment for them.
The test is performed in a recording room on E Floor, Grey Stair/Lifts, at Sheffield Children’s Hospital, S10 2TH.
The nearest entrance to the department is on Damer Street around the corner from the Emergency Department. Then follow the signs to grey lifts or stairs and travel to E floor and report to reception. You can also follow the signs for Grey lifts from the Main Entrance.
Public transport is the best way to travel to Sheffield Children’s Hospital. We are well served by bus services (51, 52, 273, 274, 275) and close to the tram route. Find out more on our public transport webpage: www.sheffieldchildrens.nhs.uk/patients-and-parents/public-transport
Please allow plenty of time for delays and roadworks. For up-to-date parking information visit our webpage on parking:
We have no provision for accompanying children to be supervised whilst your child is having the EMG. If you have any problems arranging childcare, please ring the department to discuss this. 0114 271 2129
Before you have the test, you should make sure your child:
On the day of your child’s test, we will take them into the room where the test will be done. We will make them comfortable in an appropriate position on a couch, in their pushchair or on your knee. If their hands or feet are cold then we will put them in warm water. This is because if they are cool it can affect the results. At this time you will be able to ask any questions you have.
There are 3 parts to the test and these are described below. Your child may not need all 3. It depends on the clinical problem and the doctor’s findings during the test.
During the test they will need to stay as still and relaxed as possible. First we clean the skin with an alcohol wipe. This improves contact between their skin and the rings or pads which gives better results. Then the nerves supplying sensation are tested using rings on the fingers or buttons on other parts of the body. For a short time they will feel a repetitive tapping or tingling sensation.
We will also measure between the electrodes using a tape measure and a marker pen. This means small dots are made on the skin but these will wash off. The test checks the sensory nerves for any delays in sending messages along your child’s limbs.
This part of the test allows us to check the nerve supply to the muscles. Your child will feel a tapping or tingling sensation similar to that felt during part 1, this time it sends a message to the muscle. The muscle we are testing gives a small twitch. Then we will mark points and take measurements. Any delays in the message being sent can give valuable information to the doctor about the nerve supply.
To look at the EMG signals, we will need to insert a small needle into the muscles to be tested. The needle we use is for single use and is disposed of after each child. It is designed to carry a very fine recording wire.
The doctor will examine the electrical activity whilst the muscle is at rest. During the next part of the test we will ask your child to use their muscles, so that we can observe their pattern of activity. The activity is displayed on a screen and can be heard on a speaker as a crackling sound. We may repeat the test for different muscles. This activity helps the doctor to decide whether the problem is a disorder affecting the nerve supply to the muscle or a disorder of the muscle itself. This is very important when making a diagnosis.
We must have your consent for any procedure beforehand. Staff will explain all the risks, benefits and alternatives before they ask for your consent. If you are not sure about any aspect of the proposed procedure, please do not hesitate to ask for more information.
You will not get the results on the same day because we will need to make further measurements and analysis. The consultant who referred your child for the test will be sent a report by post within 5 working days.
If you would like any further information please ring:
Department of Clinical Neurophysiology
0114 271 2129
Monday to Friday 8.30am to 4.30pm
Please note this is a generic information sheet relating to care at Sheffield Children’s. The details in this resource may not necessarily reflect treatment at other hospitals. This information is not intended as a substitute for professional medical care. Always follow your healthcare professionals’ instructions. If this resource relates to medicines, please read it alongside the medicine manufacturer’s patient information leaflet. If you have specific questions about how this resource relates to your child, please ask your doctor.
Switchboard: 0114 271 7000
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