Céline Dion will tell what it is like to live with her neurological disease in a documentary: “I will not allow it to define me” The singer revealed a year ago that she has been diagnosed with the so-called stiff person syndrome, a rare and autoimmune condition that causes spasms that make it difficult for her to walk and sing. The documentary will be directed by Irene Taylor, who in 2009 was nominated for an Oscar for a short documentary called The Final Inch.