Nerve conduction studies

Your nerves are similar to electrical cables. They use electrical impulses to facilitate communication between your brain and other parts of your body. Your brain sends signals in the form of electrical impulses that travel to your nervous system via your spinal cord, which starts at your brain stem and runs all the way down your back.

These nerves can be motor nerves (attached to your muscles and responsible for contraction) or sensory nerves (responsible for feeling things like heat or touch). If your nerves are damaged, the speed of your nerve impulses is reduced. Nerve conduction tests allow your consultant to confirm the speed (or conduction velocity) of your nerve impulses.

If you are experiencing muscle weakness, tingling, or numbness in your extremities (arms, legs, hands, feet) or face, muscle cramps or spasms, or paralysis of any muscles, you may need a nerve conduction study test. There are a number of conditions that a nerve conduction study test can help to diagnose. Some of these include:

Carpal tunnel syndrome

This is a common condition that occurs when your median nerve (a nerve that starts at your arm and goes down to your hand), which passes through your carpal tunnel, becomes compressed, leading to pain, numbness, and weakness in your hand, making it hard to grip objects and do certain daily activities. Your carpal tunnel is a narrow passageway surrounded by bones and ligaments on the lower palm side of your hand. If this area narrows due to swelling - maybe because of an injury or a specific condition like rheumatoid arthritis - it squeezes your median nerve.

Herniated disc

Also known as a slipped disc, a herniated disc occurs in instances where the soft jelly-like centre of the cushions (discs) that lie between your spinal bones (vertebra) is pushed out of the rubbery exterior of your disc due to a tear of this area. This tends to affect your lower back, and often happens because of a sudden twisting motion.

Due to the damage caused to the cushions responsible for supporting the shape of your spine, your nerves end up pressing against your spinal canal, leading to pain and numbness in the affected area.

Chronic inflammatory polyneuropathy and neuropathy

Chronic inflammatory polyneuropathy and neuropathy refers to a rare neurological condition (a condition affecting your brain) that causes inflammation of your nerve roots and the destruction of the fatty protective surface (known as your myelin sheath) that covers your nerve fibres (the part of the nerve that conducts electrical impulses). Damage to your myelin sheath leads to your nerve signals slowing down, which can lead to weakness, paralysis, or impaired motor function - usually in your arms and legs.

Sciatica

A fairly common condition, found usually with older people, sciatica occurs when your sciatic nerve (the nerve that runs from your lower back down to your feet) becomes irritated or compressed. This can happen for a number of reasons, such as a slipped disc or bone spurs (growths that form on your bones, usually due to arthritis or a fracture). Sciatica can cause swelling, pain, and numbness in your leg.

Guillain-Barré syndrome

Guillain-Barré syndrome is a condition that occurs when your immune system, which is usually responsible for attacking dangerous invading organisms that cause viruses or infections, starts to attack your nerves instead. When this happens, the protective covering around your nerves (myelin sheath) becomes damaged. This damage means that your nerves can no longer transmit signals to your brain, leading to weakness, numbness, and even paralysis - typically starting at your toes or feet.

Charcot-Marie-Tooth disease

This is an inherited condition that leads to damage to your motor and/or sensory peripheral nerves, which can cause muscle weakness, atrophy (when body tissue degenerates), and even sensory loss (deafness or blindness). You will initially feel these symptoms in the muscles of your lower arms, legs, hands, and feet. This happens because you are no longer able to effectively send electrical signals around your body.

ALS

ALS (amyotrophic lateral sclerosis), sometimes referred to as Lou Gehrig's disease, is a nervous system disease that effects the nerve cells in your brain and spinal cord. Your motor neurons reach from your brain to your spinal cord, ahead of your spinal cord transmitting these motor neurons throughout the body, allowing for movement to occur. With ALS, your motor neurons degenerate, which means your brain can no longer control muscle movement, causing you to lose the ability to speak, eat, move, and breathe.

Your consultant will begin by taking a medical history, asking about where you feel your pain or numbness, what started it, how long it's been going on for, and whether you've had any treatments for the issue already. Once they have a picture of what your symptoms are and where you feel them, they may do a physical examination of your affected area, taking care to see where and when you feel discomfort. Some of these tests may involve:

• Pressing down or tapping along the affected area to check for any tingling sensations
• Holding the affected area to see if there's any numbness or tingling
• Checking for weakness or reduced function in your affected muscles by asking you to do a physical exercise that tests out your muscle
• Delicately tapping your affected area while your eyes are closed to see how sensitive it is

Your consultant may also do an MRI scan. This scan uses powerful magnetic waves to produce clear images of your soft tissues (ligaments, muscles, tendons, cartilage) and enables your consultant to see if they are pressing against one of your nerves, along with helping them check if there are any problems with your nerve itself.

To properly understand the nature of your problem and confirm that your symptoms are due to issues with your nerves, your consultant may suggest a nerve conduction test. This is typically done alongside an EMG (electromyography) test, which detects whether your muscle is working properly in response to your nerve signals.

You won't need to do much preparation for your nerve conduction study test. Nonetheless, there are some things that you'll need to consider before coming to the hospital. Your consultant will speak to you about these at your initial consultation.

Check medications

Your consultant will ask you about the medications you are taking. If you are on muscle relaxants or drugs that block the action of acetylcholine (which is responsible for neurotransmission between muscles), they may ask you to stop taking these a few days before your nerve conduction test.

You should also note if you have a pacemaker or cardiac defibrillator (a small device used if you have dangerously abnormal heart rhythms), as special steps will need to be taken before the nerve conduction test if you have one of these devices.

Avoid lotions or perfumes

You'll need to avoid using lotions, oils, or perfumes on your skin in the days leading up to your nerve conduction test. This is due to the fact that these substances can make it harder for the electrodes to properly stick to your skin.

Keep a regular temperature

Nerve conduction studies do not work as effectively if you are too cold, because this may slow down the waves of electricity during the test. So, take care to stay warm ahead of your visit to the hospital.

Remove jewellery

If your consultant is going to do nerve conduction tests on your hands, please remove any bracelets, rings, or watches in advance, as these can interfere with the test as well. Don't worry if you're unable to remove a ring; we can safely work around it.

Nerve conduction studies are done on an outpatient basis, meaning you'll be able to go home on the same day. Sometimes they are carried out as part of your treatment during a longer stay in hospital. The test can last anywhere between 15 minutes and an hour, depending on how many areas of your body need to be studied, and generally follows these steps:

• You will change into a hospital gown and be asked to either sit or lie down on the treatment table
• Your consultant will pinpoint the nerve(s) to be studied
• Once they have located the appropriate nerves, your consultant, using a special paste, attaches a recording electrode the skin that sits over your nerve
• Your consultant then places another stimulating electrode away from the recording electrode at a specified distance
• A mild and brief electric shock is given through the stimulating electrode, which causes your nerve to send electrical signals (you may experience minor discomfort for a few seconds)
• The stimulation of your nerve and the speed of its response to these electrical impulses will be displayed on a monitor, allowing your consultant to see if there are any problems with your nerve

Your consultant will remove the paste that was used to attach your electrodes. After nerve conduction studies, you can return to your normal activities on the same day, such as driving and working, unless your consultant advises you otherwise. They may suggest that you avoid doing any physically strenuous activities for the rest of the day.

There are no reported side effects of nerve conduction tests. You may feel a slight tenderness or tingling at the site where the tests took place, but this will not last for long. In extremely rare cases, you might have some bruising.

When you choose to go private with Circle Health Group, you can expect:

• Flexible appointment times and locations to fit your routine
• The freedom to choose which hospital and consultant aligns best with your needs
• Personalised, consultant-led treatment plans tailored to your particular requirements
• Comfortable and safe private facilities maintained by expert multidisciplinary teams
• Private ensuite rooms as standards and delicious healthy meals
• Affordable, fixed-price packages with aftercare included
• Flexible payment options to help you spread the cost of your care

If you would like to learn more about nerve conduction studies, or receive support for a nerve-related condition, book your appointment online today or call a member of our team directly on 0141 300 5009.

Content reviewed by Circle in-house team in January 2023. Next review due January 2026.

1. Nerve conduction studies, Patient Info
2. EMG and nerve conduction study, WebMD
3. EMG and nerve conduction studies, Medline Plus
4. Guillain-bare syndrome, Mayo Clinic
5. Nerve conduction studies, John Hopkins Medicine