What is stiff person syndrome, the condition Celine Dion is battling?

Key Facts

CNN — Complications from stiff person syndrome, a rare neurological condition that causes spasms and muscle rigidity, have caused singer Celine Dion to cancel her “Courage World Tour” dates through 2024, according to a statement posted Friday on the star’s social media account.
I want you all to know, I’m not giving up… and I can’t wait to see you again!” Stiff person syndrome is characterized by muscle rigidity and spasms, heightened sensitivity to stimuli such as sound and lights, and emotional distress that can cause muscle spasms, according to the National Institute of Neurological Disorders and Stroke.
“Many patients, if not all, have an anxiety that is intrinsic to the disease and that anxiety actually feeds on the physical ailments of the disease that people can have,” Dr. Scott Newsome, director of the Stiff Person Syndrome Center, said in a video on the organization’s website.
At times, people with stiff person syndrome may be afraid to leave their homes because “street noises, such as the sound of a car horn, can trigger spasms and falls,” the NINDS noted.