At the Washington University ALS Center, we’re here to help you understand the disease. We’re committed to supporting patients and their families at each step of the ALS journey, offering education and resources along the way.

What is ALS?

ALS is a progressive adult-onset disease resulting in weakness, muscle atrophy and stiffness. The muscle atrophy and weakness are caused by loss of the motor neurons. These cells are the connection between your spinal cord and muscle. When these cells are lost, the muscles become atrophied and weak. Muscles in the arms and legs as well as those for speaking, swallowing, and breathing can be affected. The nerve cells that connect your brain with the spinal cord can also be affected. When these cells are not working properly, movements are slow and feel stiff. The combination of muscle atrophy, weakness, and slowness/stiffness is the way that doctors recognize that the disease might be ALS.

How is ALS diagnosed?

There is no one test that tells someone that they definitely have ALS. The diagnosis is made by recognizing the typical symptoms people feel as well as the typical physical examination findings along with tests to help exclude other diseases that might mimic ALS. Each evaluation is individualized but some additional testing may include an MRI of the brain and spinal cord, EMG/NCS, and blood work. An EMG/NCS stands for electromyogram/nerve conduction studies, which is really two separate types of studies. For the electromyogram, the physician doing the test inserts a small needle into your muscles. The needle senses the electrical activity of the muscles. If muscles are disconnected from the neurons, then the electrical activity of the muscles changes. Inserting the needle into muscle is a little uncomfortable, but typically less than getting blood drawn.

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