(spasticity) A motor disorder characterized by a velocity-dependent increase in tonic stretch reflexes with increased muscle tone, exaggerated (hyperexcitable) tendon reflexes.

(spasticity) Excessive muscle contraction and reflex hyperexcitability caused by lesions involving the upper motor neurons of the corticospinal tract.

(spasticity) 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.

A form of muscle hypertonia associated with upper MOTOR NEURON DISEASE. Resistance to passive stretch of a spastic muscle results in minimal initial resistance (a "free interval") followed by an incremental increase in muscle tone. Tone increases in proportion to the velocity of stretch. Spasticity is usually accompanied by HYPERREFLEXIA and variable degrees of MUSCLE WEAKNESS. (From Adams et al., Principles of Neurology, 6th ed, p54)

(spasticity) A disorder characterized by increased involuntary muscle tone that affects the regions interfering with voluntary movement. It results in gait, movement, and speech disturbances.

Spasticity is increased, involuntary, velocity-dependent muscle tone that causes resistance to movement. The condition may occur secondary to a disorder or trauma, such as a tumor, a stroke, multiple sclerosis (MS), cerebral palsy, or a spinal cord, brain, or peripheral nerve injury.