• MDA is helping people with ALS live longer, fuller lives.
  • Since its inception, MDA has dedicated almost $325 million to ALS research and health care services.
  • MDA's nationwide network of nearly 200 specialized neuromuscular disease clinics – including 44 designated ALS centers – is the largest in the country.
  • 13,500 ALS patients are registered with MDA and have access to our specialized clinics, staffed by top health professionals skilled in the diagnosis and medical management of ALS.
  • MDA's Neuromuscular Disease Registry is helping optimize clinical outcomes and evaluate best practices in ALS care. It complements the CDC's ATSDR National ALS Registry, which focuses on the causes of ALS.

There are some specific criteria for the diagnosis of ALS known as the El Escorial criteria. (They're named after a conference center in Spain, where they were developed in 1990.)

According to the El Escorial criteria, a diagnosis of ALS requires the following:

  • signs of degneration of lower motor neurons, which are in the spinal cord and brainstem, by clinical examination or specialized testing;
  • signs of degeneration of upper motor neurons, which are in the brain, by clinical examination;
  • progressive spread of signs within a region to other regions; and
  • the absence of evidence of other disease processes that might explain the observed clinical and electrophysiological signs.

A thorough medical and family history and physical examination are the starting points of a neurologic work-up, which includes simple, in-office tests of muscle and nerve function.

If ALS is suspected, the next step is usually an electromyogram, or EMG. This test measures the signals that run between nerves and muscles and the electrical activity inside muscles to see if there’s a pattern consistent with ALS. If there is, more tests likely will be ordered.

Additional tests may include imaging of the spinal cord and brain, usually by MRI (magnetic resonance imaging), and sometimes a test of the fluid surrounding the spinal cord (spinal tap or lumbar puncture), which involves inserting a needle into the back between two lower vertebrae.

Blood tests to exclude disorders that mimic ALS are also performed. In some instances, a muscle biopsy, which involves taking a small sample of muscle under local anesthesia, is performed.

In some cases, genetic tests (performed on a blood sample) can confirm the diagnosis (see Causes/Inheritance).

However, the diagnosis of ALS is often a “rule-out” procedure. This means ALS is diagnosed after all other possibilities have been ruled out by specific tests.

Among the conditions that resemble ALS are some forms of muscular dystrophy, the neurologic conditions known as spinal-bulbar muscular atrophy and adult-onset spinal muscular atrophy, the nerve-to-muscle transmission disorder known as myasthenia gravis, and various causes of compression of the spinal cord or brainstem, such as tumors and malformations.

If your condition has been diagnosed as ALS outside a major medical center or without extensive testing, it may be worth getting a second opinion.

MDA-supported clinics and MDA/ALS centers are staffed by professionals who are highly skilled at diagnosing ALS and the conditions that resemble it.