Spasticity is stiff or rigid muscles with exaggerated, deep tendon reflexes (for example, a knee-jerk reflex). The condition can interfere with walking, movement, or speech.

See also: Muscle cramps

Spasticity generally results from damage to the part of the brain that controls voluntary movement. It may also occur when you have damage to the nerves traveling from brain down to spinal cord.

Symptoms of spasticity include:

• Exaggerated deep tendon reflexes (the knee-jerk or other reflexes)
• Scissoring (crossing of the legs as the tips of scissors would close)
• Repetitive jerky motions (clonus), especially when touched or moved
• Unusual posturing
• Carrying the shoulder, arm, wrist, and finger at an abnormal angle due to tightness of the muscle

Spasticity may also interfere with speech. Severe, long-term spasticity may lead to contracture of muscles, causing joints to be bent at a fixed position.

• Cerebral palsy
• Brain damage caused by lack of oxygen, as can occur in near drowning or near suffocation
• Brain trauma
• Severe head injury
• Spinal cord injury
• Stroke
• Adrenoleukodystrophy
• Phenylketonuria
• Neurodegenerative illness
• Multiple sclerosis

This list is not all-inclusive.