NCIt definition : Increased involuntary muscle tone caused by central nervous system disorders that
affect the regions interfering with voluntary movement. It results in gait, movement,
and speech disturbances. Representative examples of disorders causing spasticity include
brain or spinal cord injury, and multiple sclerosis.;
Alternative definition : CTCAE: A disorder characterized by increased involuntary muscle tone that affects
the regions interfering with voluntary movement. It results in gait, movement, and
speech disturbances.; NICHD: Excessive muscle contraction and reflex hyperexcitability caused by lesions
involving the upper motor neurons of the corticospinal tract.;