Single Fibre EMG (SFEMG)
This examines the communication between the nerve and muscle by using a disposable thin sterile needle to record information from the muscle – nothing is administered via the needle.
Your arm will be resting on a pillow. The needle is inserted in to a muscle in the forearm while you gently raise your fingers up from the pillow. You will be coached during the test to contract the muscle more or less depending on the response on the screen. Some minor discomfort may be felt with the needle puncturing the skin similar to the discomfort of a blood test. There may also be discomfort as you contract the muscle. Occasionally the needle may result in a bruise within the muscle. It is very important to notify staff if you are on any blood thinning medication e.g. aspirin, Plavix, warfarin, Eliquis, Xarelto, etc.
This test requires processing of all the data once it has been collated by the software, which will typically occur the following day. It is therefore very uncommon to be given a result at the time of the test for this particular assessment. The reporting neurologist will provide a summary to your treating doctor in the days following the test.
Repetitive Stimulation (Rep Stim)
This is a test that assesses the function of the peripheral nerves by measuring electrical signals produced by the nerves in response to small electrical shocks. This can be slightly uncomfortable but not painful, similar to a brief ‘static shock commonly experienced particularly in winter. You will be warned when to expect a ‘shock’.
Repetitive stimulation refers to the fact that you will receive a train of shocks one after the other, approximately one per second for 10 seconds. This will cause muscles in the area being tested to twitch. The commonest areas to test are you wrist, which will make your hand twitch; the side of the neck, which will make your shoulder twitch, and your cheek, which will make your eyelids twitch.
After the first 10 shocks, you will exercise the muscle by contracting it for one minute. The train of shocks will then be repeated after the exercise, and at 2-minute intervals until 6 minutes has passed