Tuesday, July 31, 2012

What Tests Help with Diagnosing Carpal Tunnel Syndrome?


If you have pain, pins and needles, numbness, or muscle weakness in your arm, your doctor may refer you to a neurologist. Think of a neurologist as a nerve specialist. These physicians are trained to perform and interpret tests that look at individual nerves for signs of damage. Why are these tests important? With nerve injuries, the location of the symptoms may not be the location of the damage. For instance, the nerves in your arms emerge from your spinal cord at the level of your neck, called the cervical region. So if you experience symptoms in your hand or forearm, the damage could be in your hand or forearm but it also could be coming from your neck. These tests are invaluable in determining where the damage is occurring to make sure you receive the correct diagnosis. This is especially important if surgery is being considered.

Dr. S.M. Zimmerman, a private practice neurologist in the state of Utah, suggests thinking of nerves like electrical wires. The wire is the axon and the outer covering, is the myelin sheath. If only the outer covering is damaged, it can be expected to heal easily. But if the axon itself is damaged, healing can be slower and less certain.
A nerve conduction study helps to determine the pattern of a nerve injury. "The severity of the symptoms a person is experiencing usually correlates with the severity of damage shown on a nerve conduction study and EMG, but not always. Occasionally a person has classic symptoms but normal nerve conduction studies."

nerve conduction study looks at both the nerves that make your muscles work and the nerves that provide sensation. The test measures how fast the nerve sends a signal from one point to another, called the conduction velocity. This determines if there's damage in the myelin sheath, or outer covering of the nerve. It also measures how big the response is, which tests the axon of the nerve. If the axon is damaged, it can still heal but it won't do as well as if only the sheath was damaged, explains Dr. Zimmerman.

Dr. Zimmerman explains that  during an electromyogram, or EMG, an acupuncture-like needle is placed in a muscle to act like an amplifier. The neurologist is trained to recognize subtle differences in the sound, as well as in the amplitude of the muscle response to determine if the damage is still occurring. If the damage is no longer occurring, the test indicates how recently it had occurred. The muscles are tested at rest and during an active contraction to look at recruitment. This information tells how much damage is going on in the specific muscle that is tested.

If you have numbness and tingling in your hand or forearm, be sure to see your doctor. Early detection of syndromes like carpal tunnel and cubital tunnel is important to prevent progression of symptoms. If your nerve conduction study and EMG suggest moderate to severe damage, you can expect a referral to a surgeon to further discuss your options. If, on the other hand, the injury is mild to moderate, conservative treatments like occupational therapy, splinting, or anti-inflammatory medications may be recommended. Treat Yourself Therapy has a self-treatment video on carpal tunnel syndrome that includes helpful hints to manage symptoms, how to find the right brace or splint, and appropriate exercises to manage the condition. To learn more, visit www.TreatYourselfTherapy.com/carpal-tunnel.

Treat Yourself Therapy, LLC provides innovative and inexpensive do-it-yourself videos for people unable to attend hand therapy. These videos were developed by Jessica Karge, OTR, CHT and Kathleen Papi-Baker, OTR,CHT, both certified hand therapists who have over 40 years of combined clinical experience. To learn more, visit www.TreatYourselfTherapy.com.