A person may be diagnosed with stiff person syndrome when there is no better explanation for a patient’s symptoms and diagnostic findings. The symptoms most associated with stiff person syndrome are painful spasms and muscle rigidity. The spasms most commonly start in the back and legs. However, they can also occur in the abdomen, and more rarely, in the upper torso, arms, face and neck. These spasms can be connected to events—for instance, if someone with SPS is surprised or makes a sudden movement. They can also be triggered by cold temperatures, emotional stress, certain touches or sensations and/or specific exercises.
