Diagnosis

Amyotrophic lateral sclerosis (ALS) is difficult to diagnose early because it may mimic several other neurological diseases. Tests to rule out other conditions may include:

  • Electromyogram (EMG). During an EMG, your doctor inserts a needle electrode through your skin into various muscles. The test evaluates the electrical activity of your muscles when they contract and when they're at rest.

    Abnormalities in muscles seen in an electromyogram can help doctors diagnose ALS, or determine if you have a different muscle or nerve condition that may be causing your symptoms. It can also help guide your exercise therapy.

  • Nerve conduction study. This study measures your nerves' ability to send impulses to muscles in different areas of your body. This test can determine if you have nerve damage or certain muscle diseases.
  • Magnetic resonance imaging (MRI). Using radio waves and a powerful magnetic field, an MRI produces detailed images of your brain and spinal cord. An MRI can spot spinal cord tumors, herniated disks in your neck or other conditions that may be causing your symptoms.
  • Blood and urine tests. Analyzing samples of your blood and urine in the laboratory may help your doctor eliminate other possible causes of your signs and symptoms.
  • Spinal tap (lumbar puncture). Sometimes a specialist may remove a sample of your spinal fluid for analysis. A specialist inserts a small needle between two vertebrae in your lower back and removes a small amount of cerebrospinal fluid for testing in the laboratory.
  • Muscle biopsy. If your doctor believes you may have a muscle disease rather than ALS, you may undergo a muscle biopsy. While you're under local anesthesia, a small portion of your muscle is removed and sent to a lab for analysis.
Sept. 22, 2016
References
  1. Amyotrophic lateral sclerosis (ALS) fact sheet. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/amyotrophiclateralsclerosis/ALS.htm. Accessed July 12, 2016.
  2. Elman LB. Clinical features of amyotrophic lateral sclerosis and other forms of motor neuron disease. http://www.uptodate.com/home. Accessed July 12, 2016.
  3. Maragakis NJ. Epidemiology and pathogenesis of amyotrophic lateral sclerosis. http://www.uptodate.com/home. Accessed July 12, 2016.
  4. McCluskey L. Familial amyotrophic lateral sclerosis. http://www.uptodate.com/home. Accessed July 12, 2016.
  5. Ingre C, et al. Risk factors for amyotrophic lateral sclerosis. Clinical Epidemiology. 2015;7:181.
  6. Crum BA (expert opinion). Mayo Clinic, Rochester, Minn. July 25, 2016.
  7. Galvez-Jimenez N. Symptom-based management of amyotrophic lateral sclerosis. http://www.uptodate.com/home. Accessed July 12, 2016.
  8. Elman LB, et al. Diagnosis of amyotrophic lateral sclerosis and other forms of motor neuron disease. http://www.uptodate.com/home. Accessed July 12, 2016.
  9. Miller RG, et al. Practice parameter update: The care of the patient with amyotrophic lateral sclerosis: Multidisciplinary care, symptom management, and cognitive/behavioral impairment (an evidence-based review): Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2009;73:1227.
  10. Neurological diagnostic tests and procedures. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/misc/diagnostic_tests.htm. Accessed July 12, 2016.
  11. Choudry RB, et al. Disease modifying treatment of amyotrophic lateral sclerosis. http://www.uptodate.com/home. Accessed July 12, 2016.
  12. ALS Association chapter support groups. The ALS Association. , http://www.alsa.org/community/support-groups/. Accessed July 12, 2016.
  13. Services in your community. The ALS Association. http://www.alsa.org/community/certified-centers/. Accessed July 12, 2016.
  14. Riggin ER. Allscripts EPSi. Mayo Clinic, Rochester, Minn. May 10, 2016.