Celine Dion and her son at the Grammys

The main symptoms of SPS are muscle stiffening and spasming, which can be triggered by environmental stimuli like loud noises and can calm down when the stimulus is gone. Currently there is no cure for SPS, but the disease can be treated by methods including the use of muscle sedatives and relaxants. The star is rarely seen in public since her diagnosis. In November, she made her first appearance in three years, reportedly singing a few notes at a hockey game in Las Vegas. Last month it was revealed a documentary will be released following the singer as she lives with her illness on Amazon Prime Video.