A tuning fork, that is vibrating, will be used on specific bony prominences (your elbows, wrists, hips, the outside of your knees, ankles, fingers & toes). You will be asked if you feel the vibration, when it starts and when it stops.

    Your reflexes will be tested : your feet (Plantar or Babinski)will be tested with a dull object that is run from your heels, up the middle of the soles of your feet and across the balls of your feet quickly; your ankles (Achilles),your knees (Patellar), your wrists (Brachioradialis), and your elbows (Biceps) are tested with a “reflex hammer”; and your abdomen (Abdominal))is tested by running an object quickly and lightly across the skin of your abdomen. These tests are done to find out if your reflexes are normal . The Plantar or Babinski reflex causes your toes to automatically curl if it is normal. It is only abnormal, when the brain or spinal cord are involved, so the results of testing this reflex are important in the diagnosis of CMT to help rule out diseases in the brain.

    In CMT Type I : the ankle, knee, wrist, elbow reflexes are often absent.; in CMT type II the reflexes are sometimes slow, but usually not absent , You will have your toes and fingers moved up and down by the doctor, while your eyes are closed, to find out if you know which direction they are being moved This tests for your ability to know where your body parts are, without looking at them. (Proprioreception)

    Another test of your sense of where your body is in space, is standing with your feet right together and eyes closed, if you automatically sway or fall more than you do with your eyes open, then Romberg’s sign is positive, which means you have difficulty knowing where parts of your body are and are having problems with balance.

    Once the physical examination is complete, the doctor often will ask you to have an EMG(electromyography)done . There are two parts to this test:
    The first part tests your different nerves for their ability to carry messages to the muscles,and the speed (NCV-nerve conduction velocity) at which the messages are carried . This test uses pads (electrodes) (like a heart ECG) , attached at specific points along the muscle, a very small electric shock is applied to measure the speed at which the shock travels to the muscle, causing the muscle to contract. This test is done on both motor nerves (MNCV)and sensory nerves (SNCV) In CMT Type I nerve conduction speed is slowed. In CMT Type II the nerve conduction speed is usually normal or only mildly slowed. If you have a muscle disease, the nerve conduction speed remains normal.

    The second part, tests the ability of your muscles to respond to electrical impulses supplied by the nerves. This is the uncomfortable part. Very thin needles (like those used for acupuncture) are inserted into each muscle, and the activity of the muscle is recorded on an oscilloscope (like a TV screen). The muscle activity produces a wave form, which shows normal and abnormal muscle activity. The results of this will show the condition of your muscles, whether you have a muscle disease or a nerve disease, and the areas of your body that are involved. This part of the test also helps the Neurologist decide if you have a disease of the muscles, brain or spinal cord.

    After the EMG is done, you may be asked to have Blood tests and Urine tests, especially if there is no family history. These tests are vital to the diagnosis, because they will eliminate other treatable causes of your problem. For example: diabetes, vitamin B12 deficiency, heavy metal poisoning (eg.lead), nutritional deficiencies and alcoholism etc. There are many disease which mimic CMT, which always need to be ruled out.

    A Muscle and Nerve biopsy, is the next thing the doctor may want done. A small piece of muscle and diseased nerve is removed and then examined under a microscope, and can lead to a more definite diagnosis. This test is not always advisable, due to the slow healing ability which comes with CMT. The area where the biopsy has been done, may take a long time to heal, and may be quite painful. Discussing this with your doctor prior to the test is important!

    If the doctor has found an indication of a demyelinating disease on your EMG (the covering of the nerve:Myelin Sheath) is not intact, (imagine an electric cord with the plastic cover having nicks in it), or there is a suspicion that you may have Pressure Palsies, or evidence that the disease was transmitted in a genetic X-Linked pattern by family history, you may be asked to have DNA testing done.

    The DNA testing which is currently available will only diagnose CMT type IA, HNPP (Hereditary Neuropathy with Liability to Pressure Palsies) and X-linked CMT. There is also a Blood test in the experimental stages which will be commonly available soon for CMT Type 1B. Therefore, the DNA test cannot be used to diagnose the other types of CMT yet, but can be used to rule out the Types of CMT that the tests are available for.

    Once the doctor has put all of this information together, he can then diagnose CMT, because of the known characteristics of the disease. Depending on the severity of your symptoms and family history, often the doctor can tell you if you have CMT before completing all of the tests.