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Diagnosing Amyotrophic Lateral Sclerosis

NYU Langone physicians take a compassionate and thorough approach to diagnosing amyotrophic lateral sclerosis (ALS), a rare condition that causes nerve cells in the brain and spinal cord to progressively deteriorate until the muscles no longer function. People with ALS—which is sometimes called Lou Gehrig’s disease—eventually lose the ability to initiate and control voluntary muscle movements in their arms, legs, and body, including the ability to breathe, chew, and swallow. 

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There is currently no treatment to reverse the effects of ALS; however, the earlier it is diagnosed, the more effectively its symptoms can be managed, improving the quality of life of people with this condition.

People with a family history of the disease or those experiencing symptoms of progressive muscle weakness should meet with a physician for a thorough medical evaluation.

To diagnose ALS, an NYU Langone specialist first asks about your medical history and performs a physical exam to obtain a complete picture of your health. The doctor looks for weakness in the muscles of the face, arms, or legs, as well as visible twitching of muscles. He or she may check the strength of your grip, ask if you have any problems with tripping or falling, and observe if you have any slurred speech or difficulty swallowing. 

A careful review of your symptoms can help your doctor to determine if ALS is causing your symptoms or if they are caused by a condition that resembles ALS, such as cervical (neck) arthritis. 

Your doctor may also order additional tests to confirm a diagnosis, including one or more of the following:


Your doctor may perform electrical testing of the body’s nerve functions to aid in the diagnosis of ALS. Electromyography tests how the nerves and muscles work together by measuring electrical impulses along nerves, nerve roots, and muscle tissue. The results of this testing can also clarify the best treatment, should you be diagnosed with ALS.

During this test, a technician inserts a tiny needle electrode through the skin and into the muscle. The electrode then measures the amount of electricity generated by muscle cells when they become activated by nearby nerves. 

The results of electromyography testing can help doctors distinguish between conditions that begin in the muscle, such as muscular dystrophy, and nerve disorders that cause muscle weakness, such as ALS.

MRI Scan 

A doctor may order an MRI scan to better view the internal organs. MRI uses magnetic waves and computers to create two- or three-dimensional images of the inside of the body. A doctor can use MRI to determine if there are any anatomical problems that could be causing symptoms of muscle weakness, such as compression of the nerves as they leave the spinal cord, vertebral disks that have slipped out of place, or tumors. 

If the results of these tests confirm a diagnosis of ALS, the specialists at NYU Langone offer supportive treatment that can help alleviate and manage the symptoms of ALS and improve your quality of life. If your doctor determines that your symptoms are caused by another condition, he or she can create a treatment plan or refer you to another NYU Langone doctor who specializes in treating people with that condition.

Our Research and Education in Amyotrophic Lateral Sclerosis

Learn more about our research and professional education opportunities.