History/Causes
Types of CMT
Genetics
Diagnosis/Prognosis
Treatment
Living With CMT
New Research
Interesting Tid-Bits
Interview of Child With CMT and his Family
References
Proprioception (balance and space in time) can be assessed when the doctor moves the toes and fingers up and down and the patient is asked to determine which direction they are being moved. To test sense of orientation in space the patient is asked to stand with their feet together and their eyes closed. If they sway or fall more than they would with their eyes open, then Romberg's sign is positive. This means they have difficulty knowing where parts of their body are and are having problems with balance.(5)
Several tests can be performed to show characteristic changes in the patient. An electrical recording of muscle activity, known as an electromyography (EMG), is used to aid in the diagnosis of the neuromuscular disease. �Electromyography records muscle activity during voluntary contractions and when electrically stimulated. It also determines if muscles are receiving neurological stimulation.� (1) During the test, a fine needle is inserted into the muscle. The recordings are made while the muscle is at rest, and then again during the contraction. (6)
Normal results include:
- Brief EMG activity when the needle is inserted (6)
- Muscle tissue usually shows no EMG activity when at rest or when moved passively by the examiner (6)
- When there is active contraction, spikes should appear on the recording screen (6)
-As the muscles contract more forcefully there is more EMG activity (6)
Abnormal results include:
-Electrical activity at rest (6)
- Decrease in the amplitude and duration of spikes, indicative of muscle diseases (6)
�A nerve conduction velocity test should be performed to measure how fast impulses travel through the nerves. This test may show characteristic features of CMT, but is not diagnostic of CMT.�(2) This test is often performed at the same time and with the same equipment as the EMG.(6) Surface electrodes are placed on the skin at various points over a nerve. One electrode delivers a mild shock that stimulates an electrical response in the nerve, and the others record this response as it travels through the nerve. If delayed responses exist then this is a sign of demyelination and small responses are a sign of axonopathy. Therefore, this test is used to distinguish between CMT1 and CMT2. Also, CMT types 1A and 1X can now be diagnosed by a DNA blood test.(3,4)
A nerve biopsy, which is the removal of a small piece of the nerve, can be performed to look for the swelling characteristic of CMT type 1, but this test is less commonly performed.(6) The symptoms of CMT typically progress slowly over many years, but life expectancy is not usually shortened by the disease. Most people with Charcot Marie Tooth disease are still able to lead full and productive lives.(2)
References
1Charcot-Marie-Tooth-Disease: Diagnosis. Neurology Channel. 2005. Available at: http://www.neurologychannel.com/charcot/treatment.shtml. Accessed February 16, 2005.
2Charcot Marie Tooth disease. HealthAtoZ: Your Family Health Site. 2002. Available at: http://www.healthatoz.com/healthatoz/Atoz/ency/charcot_marie_tooth_disease.jsp. Accessed February 16, 2005.
3Charcot-Marie-Tooth Disease. Medline Plus. 2005. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000727.htm. Accessed February 16, 2005.
4Donahue G. Facts About Charcot-Marie-Tooth Disease and Dejerine-Sottas Disease. MDA Publications. Available at: http://www.mdausa.org/publications/fa-cmt.html. Accessed March 28, 2005.
5How Charcot Marie Tooth is Diagnosed. Hereditary Neuropathy Foundation. 2004. Available at: http://www.hnf-cure.org/faq/faq.php?display=faq&faqnr=27&catnr=8&prog=cmt&lang=en&onlynewfaq=0. Accessed April 5, 2005.
6Smith J. Charcot-Marie-Tooth Disease. 2005. Available at: http://www.chclibrary.org/micromed/00042210.html. Accessed February 16, 2005.