What is PLS

Primary lateral sclerosis (PLS) is a rare neurodegenerative disorder characterized by progressive muscle stiffness and weakness. PLS belongs to a group of disorders known as motor neuron diseases, in which there is degeneration of the nerves that control muscle contraction. PLS is rare, but there are not yet good estimates of how frequently it occurs. The onset is usually after age 50, but there is a wide range, including onset in childhood and adolescence. It usually starts in the legs, but it may also start in the tongue or the hands. Symptoms include poor balance, weakness and stiffness, clumsiness and speech problems.

Cause:

The cause of PLS is unknown. Like other neurodegenerative disorders, there may be a combination of complex genetic and environmental influences. There is at yet, no direct evidence of a specific gene or single environmental factor that causes the majority of PLS cases, though very rarely, a specific gene mutation may cause onset in childhood or adolescence.

Diagnosis:

PLS is a clinical diagnosis. The diagnosis is based on the patient’s medical history, a physical examination and a battery of tests to exclude other conditions that could cause similar symptoms. Electromyography (EMG) is used to separate PLS from amyotrophic lateral sclerosis (ALS), another motor neuron disease.

Treatment

There is no cure yet for PLS, and there are not yet treatments available that have been shown to slow the course of PLS. Therefore, current treatments are aimed at reducing the symptoms of PLS and maintaining independence. Several medications are available that can reduce muscle stiffness.

A regular exercise and stretching program is very important in maintaining muscle function and independence. A physical therapist can develop an exercise program tailored to the individual patient, and speech therapy may be useful for those with difficulty speaking or swallowing. Assistive devices may be needed to compensate for specific disabilities, so periodic evaluation by physical and occupational therapists is beneficial.

Prognosis

There is no cure yet for PLS or other motor neuron disorders. While every patient is unique, PLS usually progresses slowly over years, or even decades.