Electro-diagnostic tests


a.k.a. (EMG/NCS)

The electro-diagnostic examination can be helpful in evaluating the cause of pain, numbness, tingling, weakness, fatigue and muscle cramping. Just as X-rays and MRIs show the anatomy of bones and soft tissues. Electro-diagnostic tests look at nerve and muscle function to see if a nerve is "pinched" or not functioning well.

Such tests can help your surgeon establish the cause of your condition, determine prognosis, and properly manage your condition.

The examination usually takes 30 to 60 minutes, sometimes longer, depending on the complexity of your condition. The testing may include nerve conduction studies (NCS) and needle electromyography (EMG).

What will I feel?

Nerve Conduction Studies (NCS)

With Nerve Conduction Studies, you will feel small shocks in the examined arm (or leg). These shocks test how well signals travel along a nerve and can help find the cause of abnormal nerve function. The small electric pulses cause a short tingling/shock-type feeling with accompanied twitching of muscles. Several nerves may need to be tested depending on the type of problem.

Needle Electromyography (EMG)

During the needle EMG portion of the examination, the clinical neuro-physiology specialist inserts a small needle into a muscle to ‘listen’ to electrical activity of the muscle. There is no shocking in this part of the exam. If there is something wrong with the muscle or nerve, abnormal sounds and signals can be detected. The muscles tested and the number of muscles evaluated depends on what kind of problem you are having.

Will this test hurt?

There is usually some discomfort when your nerves are stimulated during the Nerve Conduction Study and when the needle is inserted into the muscle during the EMG exam. Every person's tolerance for discomfort is different, but the vast majority of people get through the test without difficulty and find the discomfort of the test tolerable. A new disposable sterile needle is used for each person so there is an extremely low risk of infection.

Do I need to do anything special on the day of the test?

There are no restrictions on activity before or after the testing and there are no lasting after effects. You may take your regular medications including any pain medicines you may be taking. You will be awake for the entire test and able to talk at all times with the specialist (such as Sibte Hasan or his colleagues) performing the test. We do not provide anaesthesia or "knock you out" for the test -to do so would adversely affect the information derived.

You should inform the specialist prior to the examination if you are on blood thinners (Warfarin or Clopidogrel) or if you have haemophilia. The physician should also be informed if you have a cardiac pacemaker, implanted defibrillator, or use a TENS unit (trans-cutaneous electrical nerve stimulator).

Skin lotions affect the quality of the signals detected so please avoid using skin lotions the day of the test.

What about test results?

When the examination is complete, the specialist will analyse the results and report them back to the clinician who referred you for the test.

You may be given some verbal preliminary findings, and the final written report is sent to your clinician’s office over the coming days and a follow up appointment made for you to discuss the implications.