What are nerve conduction studies, and how are they useful?
Carpal tunnel surgery Sydney
When a person first visits a doctor to discuss problems with their hand, one of the things that the doctor may order is a type of test called nerve conduction studies. These can be used to assess the function of various nerves of the arm and hand, to determine what the best treatment options would be.
What is it like to have nerve conduction studies? What do the results mean for your treatment?
What are nerve conduction studies?
Nerve conduction studies, also known as nerve conduction velocity tests, are used to measure how quickly nerves transmit electrical impulses.
For the test, two electrodes are placed on your skin, overlying the nerve that’s being tested. One electrode is used to generate a small electrical impulse, and the other one measures to determine when that impulse reaches it. Based on the distance between the two electrodes, we can then calculate how quickly the nerve transmitted the electrical impulse.
In many cases, this test is performed alongside another test called electromyography, or EMG, which is used to assess the function of muscles. For this test, a very small needle is inserted into the muscle being tested. An electrode on this needle measures the activity of the muscle. The muscle’s activity is recorded at rest, and then you’re asked to contract (tighten) the muscle, so its activity can be recorded during activation.
Do nerve conduction studies hurt?
In general, there is only minimal discomfort with nerve conduction studies. There may be a minor sensation at the moment the electrical impulse is generated, but it doesn’t last very long. Some people describe this as feeling similar to the experience of static electricity, while others describe it as more of a tingling sensation. You will not feel any pain after the test is finished.
If EMG is also performed, then there may be some discomfort associated with the insertion of the needle. However, the needle that’s used for EMG is extremely tiny – about the size of an acupuncture needle. Some people barely feel it going in, while others feel a small pinch. You may have some tenderness or soreness in the area for a day or two afterward.
What do the results of nerve conduction studies mean?
Nerve conduction studies show how quickly your nerves are conducting electrical impulses. If the nerve is not conducting at normal speeds, this indicates that something is interfering with its function. This could be due to compression of the nerve (a “pinched nerve”), nerve damage from an injury, or a disease process causing damage to the nerve (such as diabetes).
In some cases, just one nerve may show slow conduction speeds, while in other cases, multiple nerves will be affected. When just one nerve shows signs of damage, this indicates damage to that nerve, usually from nerve compression or from an injury. If multiple nerves are affected, this is indicative of a more general disease process affecting the nerves, such as nerve damage from diabetes or from an autoimmune condition.
A muscle should normally show very little activity at rest, and should then show a smooth pattern of activation when it contracts. An abnormal EMG test may show that the muscle has activity even at rest, and/or an unusual pattern of activation as it’s being contracted. An abnormal EMG may indicate that the muscle is not being stimulated by its nerve or that the muscle itself is damaged.
Nerve conduction studies for carpal tunnel syndrome
One of the most common reasons that nerve conduction studies are ordered is for carpal tunnel syndrome. Although this condition can sometimes be diagnosed based on the symptoms alone, it’s usually recommended to have nerve conduction studies (including both nerve conduction velocity tests and EMG) before considering any type of surgical treatment for carpal tunnel syndrome. The tests are used to assess the severity of the condition, as well as to rule out any other potential causes of the patient’s symptoms.
In carpal tunnel syndrome, there’s compression of the median nerve. This is one of the main nerves to the hand, and can become compressed where it crosses a narrow passage at the wrist. When this happens, the nerve will have a slow conduction velocity. Testing of various segments of the nerve can show that conduction slows down at the wrist, which is a very strong indicator of carpal tunnel syndrome. When a muscle is not being stimulated by its nerve, then it may start to show abnormal activity at rest. In people with carpal tunnel syndrome, this may be seen on the EMG.
A similar pattern of results, involving slow nerve conduction velocities and muscle activity at rest, may be seen in people with cubital tunnel syndrome. In this condition, the ulnar nerve, which serves the pinky finger side of the hand, becomes compressed at the elbow. This pattern may also occur in people who have sustained an injury to a nerve that has affected its function.
Carpal tunnel surgery Sydney
As an expert in treating conditions of the hand and wrist, Dr. Sungaran frequently sees people with conditions like carpal tunnel syndrome. He may order nerve conduction studies in order to ensure an accurate diagnosis, and to assess the severity of the patient’s condition to determine whether surgery might be an appropriate option for them to consider.
Although he’s a surgeon, Dr. Sungaran doesn’t recommend surgery for every patient. He prefers to try more conservative options first, and then to proceed to surgery only when these methods are not effective. This thoughtful approach avoids unnecessary surgical procedures, while helping to get the best possible outcomes for patients. If you’re having problems with your hand function, and would like to have a consultation with Dr. Sungaran to receive professional advice about your options, please contact our front desk to schedule your appointment.
