Primary Lateral Sclerosis


In some cases, it can take three to four years to diagnose PLS because in the beginning, ALS symptoms may resemble those of PLS until additional symptoms emerge later on.

Tests that may be ordered include:

  • Physical examination: The diagnosis of PLS involves a series of assessments including physical and neurological examinations, review of personal and family medical history, along with specific testing. The healthcare providers will carefully evaluate the symptoms to differentiate PLS from similar conditions such as ALS or multiple sclerosis.
  • Blood tests: Possible reasons for the weakness of muscles or infections can be identified through this test.
  • Magnetic resonance imaging (MRI): Causes of symptoms, such as spinal cord tumors, multiple sclerosis, or structural issues, can be shown by an MRI. Generally, imaging tests like MRI may show evidence of damaged nerve cells in the brain or spine.
  • Nerve conduction studies: The nerves’ ability to convey impulses to muscles in different parts of the body is measured by a small amount of electrical current. Existing nerve damage can be identified during this procedure.
  • Spinal tap: During the procedure, small samples of cerebrospinal fluid are taken using a thin, hollow needle that is placed into the spinal canal. This liquid envelops the spinal cord and brain. Also referred to as lumbar puncture, this procedure can assist in ruling out infections, multiple sclerosis, and other abnormalities specific to neuromuscular conditions.
  • Electromyogram (EMG): In this test, a needle electrode is inserted through the skin into various muscles to measure their electrical signals. This can assist in distinguishing between ALS, which affects both upper and lower motor neurons, and PLS, an illness of the upper motor neurons.
    EMG measures the electrical activity in the muscles during both rest and contraction. Multiple EMGs may be required over a few years to confirm a diagnosis of PLS accurately.
  • Genetic testing: This may be recommended in suspected cases of juvenile primary lateral sclerosis.


Treatment for primary lateral sclerosis (PLS) primarily centers on managing symptoms and may encompass a range of strategies. Given that PLS cannot be halted, prevented, or reversed, the objectives revolve around preserving function and alleviating symptoms.
Treatment options include:

  • Medication: Common medications used to address PLS symptoms include baclofen, clonazepam, and tizanidine for muscle stiffness, quinine for muscle cramps, and diazepam to promote muscle relaxation. If oral medications fail to control muscle spasms effectively, surgery may be recommended to implant a medication pump that delivers baclofen directly into the spinal fluid, providing targeted relief. Drooling in PLS can be improved with medications like amitriptyline, while severe and frequent mood swings may be managed with antidepressants if necessary.
  • Physical and occupational therapies: This address muscle weakness and improve flexibility and joint mobility. Maintaining muscle strength, flexibility, and range of motion can be facilitated by strengthening and stretching activities.
  • Speech and language therapy: If PLS affects the facial muscles, speech therapy may be able to aid with swallowing and communicating.
  • Nutrition support: Special feeding techniques may be recommended to help maintain body weight despite difficulties eating caused by symptoms. Specific diet and nutritional supplements may also be prescribed.
  • Assistive devices: Specialized devices may be employed to assist with speaking difficulties. Devices such as canes, walkers, or wheelchairs may also be recommended to enhance independence and mobility.