• Reference Number: HEY-784/2023
• Departments: Neurophysiology
• Last Updated: 29 March 2023

Introduction

This leaflet has been produced to give you general information about your procedure.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor, but may act as a starting point for discussion.  If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What are EMG and NCS?

EMG and NCS are an examination of your muscles and peripheral nerves.  This is done by recording the electrical activity they produce either at rest, when moving or when being stimulated by a small electrical current.

Why do I need an EMG and NCS?

Your doctor has requested an EMG and NCS to be performed because you have reported some symptoms that raise the possibility of a problem affecting your nerves or muscles.  There are many conditions that can cause these problems. You may need either EMG or NCS or sometimes both.

Can there be any complications or risks?

• Preparation of the skin prior to the examination may cause a temporary reddening of the skin. This will fade quickly and is not uncomfortable.
• Sometimes people may find the examination uncomfortable. The sensations have been described as similar to a TENS machine (a TENS machine is a device used to help relieve pain which applies small electrical impulses to parts of the body which are felt as a tingling sensation).  They are not harmful and do not persist once the examination is over.
• The needle may cause a small amount of bleeding, and there is a small chance of localised bruising and the muscles tested may feel sore for a short time after the examination. If you are concerned about any changes please contact your GP.

How do I prepare for the EMG and NCS?

Please read this information leaflet.  Share the information it contains with your family (if you wish) so that they can be of help and support.  There may be information they need to know, especially if they are taking care of you during/following this examination.

• Your skin needs to be warm for this examination. Therefore please keep your hands and/or feet warm by wearing gloves and socks on your way to the hospital.
• Your skin needs to be free from greasy substances.  Please refrain from using skin creams/ointments for 12 hours prior to your appointment unless these have been prescribed for you.
• Wear loose fitting clothing to allow the limbs being tested to be accessed easily.
• Please remove all jewellery from your upper and/or lower limbs.  If you are unable or unwilling to remove any rings please advise a member of staff.
• Please do not bring any children with you as we are unable to accommodate them in the treatment room.  You may bring someone to supervise them in our waiting area.
• Take your medication as normal unless otherwise directed by your doctor and bring along a list of current medication with you.
• IF YOU ARE TAKING BLOOD THINNING MEDICATIONS YOU SHOULD TELL THE DOCTOR BEFORE THE TEST STARTS.

What will happen?

• On your arrival in the department we will obtain your verbal consent for the procedure before your investigation begins.
• The doctor performing the examination and anyone assisting will introduce themselves, explain the test to you and will be happy to answer any questions you may have.
• We will check your details with you and then the doctor will ask you some questions regarding your condition.  This will determine the most appropriate way of examining you and interpreting the results.
• We will measure the temperature of your hands or feet and if they are not warm enough we will ask you to sit with your hands or feet in warm water until the correct temperature is achieved.
• You will be asked to lie on a bed or sit in a chair. The doctor will place some electrodes (small sticky pads) on your skin, usually on your arms or legs. An electrical impulse will be applied to the skin and a measurement is taken.  This may be repeated in several different areas of the arms or legs.
• Depending on your symptoms the doctor may need to put a small needle into some of your muscles. This measures the electrical activity your muscles produce and how your muscles are working.
• If you require both NCS and EMG, the test will last approximately 30 to 60 minutes.

What happens afterwards?

• The electrodes will be removed from your skin/muscle.
• The results will be sent to your referring doctor. This usually takes up to two weeks.
• After both tests you will be able to continue your daily activities as normal, including driving. These tests are not a treatment but will help the doctor to understand the reasons for your symptoms.

This leaflet was produced by the Neurophysiology Department, Hull University Teaching Hospitals NHS Trust and will be reviewed in March 2026.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Neurophysiology Department on:

Tel: (01482) 675339 / 675318

This leaflet was produced by the Neurophysiology Department, Hull University Teaching Hospitals NHS Trust and will be reviewed in March 2026.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

• you must be able to give your consent
• you must be given enough information to enable you to make a decision
• you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.