PLS stands for Primary Lateral Sclerosis, which is a rare neuromuscular disease that affects the nerve cells in the brain that control movement. It is a type of motor neuron disease that causes weakness in the muscles that control the legs, arms, and tongue. Symptoms typically begin with balance trouble, and people with PLS may move slowly and be clumsy. Over time, symptoms evolve to include having trouble with their hands and arms, followed by problems with chewing, swallowing, and speaking. PLS is often mistaken for another, more common motor neuron disease called amyotrophic lateral sclerosis (ALS), but PLS gets worse more slowly than ALS. There is no cure for PLS, but treatment goals are to manage symptoms, improve muscle flexibility, assist with speaking issues, and use of assistive devices. Stretching and strengthening exercises can help maintain muscle strength, flexibility, and range of motion. Speech therapy might help with communication and swallowing if facial muscles are affected by PLS.