Add Yahoo as a preferred source to see more of our stories on Google. A muscle spasm, also known as a cramp, twitch or charley horse, is the sudden and involuntary forced contraction of a muscle.

Céline Dion revealed she's battling a rare neurological syndrome called stiff-person syndrome, which causes uncontrollable muscle spasms and makes it difficult for her to walk and sing.

Singer Celine Dion’s announcement Thursday that she has stiff-person syndrome will shed new light on a rare treatable, but incurable, condition. According to Dr. Duarte Machado of the Chase Family ...