Diagnosing Muscular Dystrophy

To determine if muscular dystrophy is causing your symptoms, NYU Langone neurologists—doctors who focus on disorders of the nervous system—perform a physical exam and speak with you about your medical history. Children receive diagnosis through Hassenfeld Children’s Hospital at NYU Langone.

Other diagnostic tools can help a doctor determine the type of muscular dystrophy or rule out other conditions affecting the muscles or nerves.

While there is currently no treatment that can stop the progression of muscular dystrophy, getting an accurate diagnosis as early as possible can help improve quality of life with the condition. 

Blood Test

A doctor may order a blood test that can detect elevated levels of creatine kinase, an enzyme released into the bloodstream when muscle fibers deteriorate. Elevated levels of this enzyme mean the muscle is being destroyed due to an abnormal process, such as muscular dystrophy or an inflammatory muscle disease.

Electromyography

Electromyography (EMG) tests how the nerves and muscles work together by measuring the electrical impulse along nerves, nerve roots, and muscle tissue. A doctor may perform an EMG to confirm a diagnosis of muscular dystrophy and to determine the best treatment for you. 

To perform this test, the doctor inserts a tiny needle—a conductor for electrical current called an electrode—through the skin and into the muscle. This allows your doctor to measure the amount of electricity generated by muscle cells when they become activated by a nerve impulse. In people with muscular dystrophy, the muscle fibers don’t respond as well to repeated electrical stimulation as do normally functioning muscles.

The results of EMG testing can help doctors distinguish between conditions that begin in the muscle and nerve disorders that mimic muscular dystrophy.

Nerve Conduction Study

A doctor may also perform a nerve conduction study to determine if there is any nerve damage. This test measures how fast an electrical impulse travels through a nerve. 

Nerves can be thought of as electrical cables that carry messages between your brain and muscles. When a nerve is not working well, it takes too long to conduct those signals. 

During a nerve conduction test, a doctor stimulates the nerve and measures the time it takes to respond. Several places along the nerve are tested, and the area where the response takes too long is likely to be the place where the nerve is compressed.

A slower electrical response in the muscles can indicate muscular dystrophy.

Genetic Testing

Genetic testing is a type of medical testing that identifies changes in a person’s chromosomes, genes, or proteins. The results of genetic testing can help to confirm or rule out a diagnosis of muscular dystrophy.

These results can also provide doctors with recommendations for appropriate medical management; provide information to inform other testing options, including carrier and reproductive prenatal diagnosis; and determine if other relatives are at risk for the disorder. 

Genetic testing is also important if you wish to participate in a clinical trial—a research study to test the effectiveness of new therapies. Some trials may only be open to people with certain types of muscular dystrophy. 

A blood test is usually performed for genetic testing, but specialists may also use a cheek swab, skin biopsy, or muscle biopsy.

Muscle Biopsy

If genetic testing is unable to identify the type of muscular dystrophy, the doctor may recommend a muscle biopsy. This test can give the specialist more information about what is occurring inside the muscles.

A muscle biopsy is a surgical procedure performed using anesthesia. The doctor removes a small piece of affected muscle tissue. An examination of this sample can help the doctor to distinguish between the presence of muscular dystrophy and other inflammatory disorders, such as polymyositis and dermatomyositis, and to possibly determine which type of muscular dystrophy is causing your symptoms.

NYU Langone doctors use the results of these diagnostic tests to create a customized care plan that helps you to manage muscular dystrophy symptoms throughout your life.