There is no single test that confirms a diagnosis of primary lateral sclerosis (PLS). In fact, because the disease can mimic signs and symptoms of other neurological diseases such as multiple sclerosis and ALS, your doctor is likely to order several tests to rule out other diseases.

After taking a careful record of your medical history and family history and performing a neurological examination, your doctor might order the following tests:

  • Bloodwork. Blood tests check for infections or other possible causes of muscle weakness.
  • MRI. An MRI or other imaging tests of your brain or spine might reveal signs of nerve cell degeneration.

    An MRI can show other causes of your symptoms, such as structural abnormalities, multiple sclerosis or spinal cord tumors.

  • 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.

    This test can measure the involvement of lower motor neurons, which can help to differentiate between PLS and ALS.

  • Nerve conduction studies. These tests use a low amount of electrical current to measure your nerves' ability to send impulses to muscles in different areas of your body. This test can determine if you have nerve damage.
  • Spinal tap (lumbar puncture). Your doctor uses a thin, hollow needle to remove from your spinal canal small samples of the fluid that surrounds your brain and spinal cord (cerebrospinal fluid) for laboratory analysis. A spinal tap can help rule out multiple sclerosis, infections and other conditions.

Sometimes doctors wait three to four years before finalizing a diagnosis because early ALS can look just like PLS until additional symptoms surface a few years later. You might be asked to return for repeat electromyography testing over three to four years before the PLS diagnosis is confirmed.


There are no treatments to prevent, stop or reverse PLS. Treatment, which focus on relieving symptoms and preserving function, include:

  • Medication. Your doctor might prescribe medication such as baclofen, tizanidine (Zanaflex) or clonazepam (Klonopin) to relieve muscle spasms (spasticity). These medications are taken by mouth.

    If your spasticity isn't controlled with oral medication, your doctor might recommend surgically implanting a medication pump to deliver baclofen directly to your spinal fluid (intrathecal baclofen).

    If you have depression, your doctor might prescribe antidepressants. Amitriptyline and other drugs also can help drooling problems.

  • Physical therapy. Stretching and strengthening exercises can help maintain muscle strength, flexibility and range of motion, and prevent joint immobility. Heating pads can help relieve muscle pain.
  • Speech therapy. If your facial muscles are affected by PLS, speech therapy might help.
  • Assistive devices. Physical or occupational therapists might evaluate you periodically to determine whether you need assistive devices, such as a cane, walker or wheelchair, as PLS progresses.

Coping and support

Periods of feeling down about having primary lateral sclerosis are expected and normal. Dealing with the reality of an incurable, progressive disease can be challenging. To cope with the disease and its effects, consider these tips:

  • Seek emotional support. Family and friends can be great sources of comfort and support when you're wrestling with the emotional aspects of long-term disease.

    Because PLS is an uncommon diagnosis, it might be a challenge to find a local support group for people with your condition. However, some online discussion groups are available. It might help to see how others cope with the disease.

  • Get professional help if you need it. When faced with a chronic illness, it's not unusual to become overwhelmed at times. Seek professional counseling for another perspective, or if you're struggling with depression and need advice on treatment.

  • Know and use resources available to you. If you reach a point where your disease is restricting your activities significantly, ask your doctor about devices designed to help you stay independent.

    In addition, there are social services available to people with disabilities of all kinds. Try to learn all you can about the resources available to you. Sometimes relying on your community for help can strengthen ties in new ways.

June 28, 2019
  1. Daroff RB, et al. Disorders of upper and lower motor neurons. In: Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. https://www.clinicalkey.com. Accessed June 13, 2019.
  2. Primary lateral sclerosis information page. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/Disorders/All-Disorders/Primary-Lateral-Sclerosis-Information-Page. Accessed June 13, 2019.
  3. Elman LB, et al. Clinical features of amyotrophic lateral sclerosis and other forms of motor neuron disease. https://www.uptodate.com/contents/search. Accessed June 13, 2019.
  4. Jorgensen S, et al. Motor neuron diseases. In: Braddom's Physical Medicine and Rehabilitation. 5th ed. Philadelphia, Pa.: Elsevier; 2016. https://www.clinicalkey.com. Accessed June 13, 2019.
  5. Primary lateral sclerosis. Genetic and Rare Diseases Information Center. https://rarediseases.info.nih.gov/diseases/10684/primary-lateral-sclerosis. Accessed June 13, 2019.
  6. Juvenile primary lateral sclerosis. Genetics Home Reference. https://ghr.nlm.nih.gov/condition/juvenile-primary-lateral-sclerosis. Accessed June 13, 2019.
  7. Elman LB, et al. Diagnosis of amyotrophic lateral sclerosis and other forms of motor neuron disease. https://www.uptodate.com/contents/search. Accessed June 13, 2019.


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