NORD’s Rare Disease Video Library provides brief stories from patients, parents and caregivers about living with a rare disease.
Stiff-person syndrome (SPS) is a rare acquired neurological disorder characterized by progressive muscle stiffness (rigidity) and repeated episodes of painful muscle spasms. Muscular rigidity often fluctuates (i.e., grows worse and then improves) and usually occurs along with the muscle spasms. Spasms may occur randomly or be triggered by a variety of different events including a sudden noise or light physical contact. In most cases, other neurological signs or symptoms do not occur. The severity and progression of SPS varies from one person to another. If left untreated, SPS can potentially progress to cause difficulty walking and significantly impact a person’s ability to perform routine, daily tasks. Although the exact cause of SPS is unknown, it is believed to be an autoimmune disorder and sometimes occurs along with other autoimmune disorders.
Stiff-person syndrome has been described in the medical literature under many different, confusing names. Originally described as stiff-man syndrome, the name was changed to reflect that the disorder can affect individuals of any age and of either gender. In fact, most individuals with the condition are women. Stiff-person syndrome is considered by many researchers to be a spectrum of disease ranging from the involvement of just one area of the body to a widespread, rapidly progressive form that also includes involvement of the brain stem and spinal cord (PERM).