Type keyword(s) to search Getty Images What is Spasticity? The condition affects more than 12 million people around the world. Here, how to spot symptoms, plus information on its multiple treatment options. Jul 28, 2021 What is spasticity? Spasticity may be a term that’s new to you, but it’s a condition that affects more than 12 million people around the world. [8] It’s a complicated condition, but simply put, it’s extreme muscle tightness that can cause spasms or pain that make it hard to move or speak normally. Muscle movement is usually controlled by a complex system in the brain and spinal cord that allows some muscles to contract (tighten) while others relax. Damage to the brain or spinal cord—from conditions such as a stroke, spinal cord injury, or brain trauma—can disrupt the brain’s communication with the body, making the muscles contract all at once, causing spasticity. [5] The result of that lack of communication and tense muscles can mean stiff, rigid muscles that make movement, speech, and other daily-life functions difficult, [2] or, in more severe cases, joints that severely bend and will not unbend. [1]