SCLS or Stiff Person Syndrome is a rare neurological disorder that can cause muscle stiffness, spasms, and cramps. Some synonyms for SCLS include stiff person disease, stiff man syndrome, and Moersch-Woltman syndrome. While the exact cause of SCLS is unknown, it is thought to be an autoimmune disorder that affects the nervous system. Treatment for SCLS usually involves the use of medications, such as benzodiazepines and muscle relaxants, to help manage symptoms. Physical therapy and other supportive treatments may also be recommended. If you are experiencing muscle stiffness or other symptoms, it is important to speak with a healthcare provider to determine the cause and appropriate treatment.