Spasticity

Abstract

Spasticity is a component of many neurological conditions, including multiple sclerosis (MS), cerebral palsy, spinal cord injury, stroke, and brain injury. First described in the 19th century, spasticity is a velocity-dependent increase in stretch reflex activity. Peter Nathan described it as “a condition in which stretch reflexes that are normally latent become obvious. The tendon reflexes have a lowered threshold to tap, the response of the tapped muscle is increased, and usually, muscles besides the tapped one respond; tonic stretch reflexes are affected in the same way” (1). Although appearing straightforward, a search of current literature shows that there is disagreement over the exact definition of spasticity. Some authors include clonus, hyperactive tendon reflexes, and spasms, whereas others find these physical findings to be associated with spasticity but separate from what is a more restricted definition of velocityassociated increased muscle tone.