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 also 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 also measures the involvement of lower motor neurons, which can help to differentiate between PLS — an upper motor neuron disease — and ALS, which affects both upper and lower motor neurons.
- 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 inserted into your spinal canal to remove 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 3 to 4 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 3 to 4 years before the PLS diagnosis is confirmed.
Genetic testing may be done when juvenile PLS is suspected. Genetic counseling also may be recommended.
There are no treatments to prevent, stop or reverse primary lateral sclerosis. Treatment, which focuses on relieving symptoms and preserving function, can include the following options.
Your doctor might prescribe medication to relieve symptoms:
Muscle spasms (spasticity). Spasticity may be relieved by medications such as, baclofen, tizanidine (Zanaflex) or clonazepam (Klonopin). 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).
- Emotional changes. If you have frequent, rapid and intense shifts in emotions, your doctor might prescribe antidepressants.
- Drooling. Drooling may be helped by amitriptyline or other drugs.
Physical and occupational therapies
Stretching and strengthening exercises can help maintain muscle strength, flexibility and range of motion and prevent joint immobility.
Speech and language therapy
If your facial muscles are affected by PLS, speech therapy might help with communication and swallowing.
If you experience difficulty with chewing and swallowing that make eating difficult, a nutritionist can offer diet tips, nutritional supplements or special feeding methods to help maintain your body weight.
As PLS progresses, physical or occupational therapists may evaluate you periodically to determine whether you need assistive devices, such as a brace, cane, walker or wheelchair. Assistive technology devices may help with communication.
Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.
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 coping 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. Your health care team may have some suggestions.
- 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 have 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.
Aug. 21, 2021