Spasticity is a condition in which muscles become stiff or tight, making movement difficult or less fluid. It is marked by an involuntary, velocity-dependent increase in muscle tone, which means that the affected muscles become more resistant to movement the faster that they are moved. Common symptoms include muscle stiffness and spasms that can interfere with daily activities, abnormal posture, exaggerated reflexes, pain, and difficulty with movement.

Spasticity can affect people of any age, from infants to older adults, and is not limited by sex or race. It is estimated that more than two million people in the United States experience spasticity. The condition is especially common in people with neurological disorders: more than 90% of people with cerebral palsy, up to 70% of those with multiple sclerosis, around 36% of those with spinal cord injury, up to 45% of those with stroke, and up to 50% of people with traumatic brain injury (TBI) are affected.

Although spasticity can be challenging, there are many effective treatments available. With the right combination of therapies, medications, and support, many people with spasticity can experience improved comfort, function, and quality of life.

In a healthy nervous system, the brain and spinal cord send balanced signals to the muscles, allowing them to contract and relax smoothly as needed for movement, posture, and daily activities. When someone has spasticity, this balance is disrupted. Some muscles receive abnormal signals from the brain or spinal cord, leading to an exaggerated increase in muscle tone. This causes the affected muscles to become stiff, tight, or resistant to movement. It’s especially noticeable when a muscle is stretched quickly.

Spasticity can involve only a few muscles or be widespread, affecting large areas of the body. The condition can range from mild, causing only minor discomfort, to severe, resulting in significant disability, discomfort, and loss of independence. The pattern and severity of spasticity can vary greatly from person to person, depending on which parts of the nervous system are affected. It can also be worse with activity or stress.

Spasticity is caused by damage or disruption to the parts of the brain or spinal cord that control voluntary movement and muscle tone. This damage interrupts the normal balance of signals that regulate muscle contraction and relaxation, leading to increased muscle tone and stiffness.

The most common causes of spasticity include neurological conditions such as stroke, cerebral palsy, multiple sclerosis, TBI, and spinal cord injury. Other possible causes are brain damage from lack of oxygen (such as after near drowning or suffocation), infections of the brain or spinal cord (such as Lyme disease, syphilis, HIV, or tuberculosis), tumors in the brain or spinal cord, neurodegenerative diseases, phenylketonuria (PKU, a rare, inherited condition in which the body is unable to correctly break down phenylalanine, an amino acid), and vitamin or mineral deficiencies (such as vitamin B12, vitamin E, or copper). In rare cases, toxins (such as nitrous oxide) can cause spasticity.

Spasticity typically affects the upper motor neurons—nerve cells in the brain and spinal cord that send signals to the muscles. When these pathways are damaged, the normal inhibitory signals—nerve messages from the brain and spinal cord that act like brakes to hold reflexes in check and direct muscles to relax—are reduced or lost, resulting in overactive reflexes and increased muscle stiffness.

Risk factors for spasticity include:

• Stroke
• Cerebral palsy
• Multiple sclerosis
• Spinal cord injury
• TBI
• Neurodegenerative diseases, conditions in which nerve cells in the brain or spinal cord are progressively damaged over time, such as amyotrophic lateral sclerosis (ALS), hereditary spastic paraparesis (also called hereditary spastic paraplegia, HSP), and adrenoleukodystrophy (ALD)
• Brain damage from lack of oxygen
• Infections of the brain or spinal cord
• Tumors in the brain or spinal cord
• PKU
• Vitamin or mineral deficiencies (such as vitamin B12, vitamin E, or copper)
  

Symptoms of spasticity may include:

• Muscle stiffness or tightness
• Increased muscle tone
• Muscle spasms, which may be painful or uncontrollable
• Exaggerated reflexes
• Abnormal posture
• Involuntary crossing of the legs
• Difficulty with walking or movement
• Decreased mobility or impaired limb function
• Muscle fatigue
• Pain in affected muscles or joints
• Repetitive, jerky motions
• Difficulty with daily activities such as dressing, bathing, or eating
• Speech difficulties (if muscles involved in speech are affected)
• Problems with hygiene or comfort
• Sleep disturbance
  

To diagnose spasticity, your doctor will review your medical history, conduct a physical exam, and may order one or more diagnostic tests.

Your doctor will ask you about your symptoms, when they began, how severe they are, which muscles are affected, and whether you have any underlying neurological conditions or risk factors. During the physical exam, your doctor will assess muscle tone, strength, reflexes, range of motion, and look for signs such as abnormal posture, involuntary muscle contractions, or joint deformities. The doctor may also evaluate how spasticity affects your ability to perform daily activities and may use standardized rating scales, such as the Modified Ashworth Scale or Tardieu Scale, to measure the severity of muscle stiffness.

Additional tests are sometimes necessary to help confirm the diagnosis or to identify underlying causes, including:

• Electromyography (EMG): Measures the electrical activity of muscles and can help distinguish spasticity from other muscle disorders.
• Nerve conduction studies: Assess how well electrical signals travel through your nerves.
• Imaging studies, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans: Used to look for damage or abnormalities in the brain or spinal cord that may be causing spasticity.
• Laboratory tests, such as blood tests or urine tests: May be ordered to rule out infections, metabolic disorders, or other conditions that can contribute to spasticity.

Your doctor may also look for factors that can worsen spasticity, such as infections, pain, pressure sores, or medication changes, to ensure a comprehensive evaluation.

There is no cure for spasticity, but a variety of treatments can help manage symptoms, improve comfort, and enhance quality of life. Treatment plans are tailored to each person’s needs and may involve a combination of therapies.

Main treatments for spasticity include:

• Physical therapy: Involves stretching, strengthening, and range-of-motion exercises to maintain or improve mobility, reduce muscle stiffness, and prevent contractures.
• Occupational therapy: Focuses on improving fine motor skills and daily activities and may include training in strategies or the use of devices to assist in performing daily tasks.
• Speech therapy: Helps those whose spasticity affects speech or swallowing.
• Splinting, casting, and bracing: Use of devices to support and position affected limbs, prevent contractures, and improve function.
• Oral medications: Medicines such as baclofen, tizanidine, dantrolene, clonidine, and diazepam can help reduce muscle tone and spasms, though they may cause side effects such as drowsiness or weakness.
• Botulinum toxin injections: Injections into specific muscles to temporarily reduce muscle overactivity and improve movement or ease of care.
• Intrathecal baclofen pump: The pump is surgically implanted in the abdomen. It delivers baclofen, a skeletal muscle relaxant, directly to the spinal fluid, providing targeted relief for severe spasticity with fewer side effects than oral medications.
• Chemical nerve blocks: Injections of agents such as phenol or alcohol to temporarily reduce nerve activity in targeted muscles.
• Electrical stimulation: Use of electrical currents to stimulate weak muscles or reduce spasticity.
• Surgery: Procedures such as tendon lengthening, tendon transfer (repositioning a tendon to improve movement), contracture releases, or joint fusions may be performed to improve contractures and function. Newer nerve-based procedures by peripheral nerve surgeons can reduce or eliminate tone in muscles to permanently reduce spasticity. These are often performed in combination on a limb to suit a patient’s goals. In severe cases, selective dorsal rhizotomy (a procedure that involves cutting specific sensory nerve fibers in the lower spine to reduce spasticity and improve muscle function) may be performed.

A team approach involving doctors, therapists, patients, and caregivers is often needed to create the most effective treatment plan for each individual.

People with spasticity may be at increased risk for certain complications, including:

• Contractures: Permanent tightening of muscles, tendons, or joints that limit movement and flexibility.
• Joint deformities: Abnormal positioning or shape of joints due to prolonged muscle stiffness.
• Pressure sores: Skin breakdown caused by difficulty moving and maintaining proper positioning.
• Pain: Discomfort or aching in affected muscles or joints.
• Difficulty with hygiene: Challenges in cleaning and caring for the body due to limited movement.
• Impaired mobility: Trouble walking, moving, or performing daily activities.
• Sleep disturbances: Difficulty sleeping due to muscle spasms or discomfort.
• Bone fractures: Increased risk of broken bones due to falls or abnormal muscle forces.
• Urinary tract infections: Increased risk due to difficulty with bladder function or hygiene.
• Chronic constipation: Ongoing difficulty with bowel movements.
• Frozen joints: Joints that become immobile due to long-term stiffness.
• Increased risk of subluxation or dislocation: Partial dislocation (subluxation) or complete displacement of a joint.
• Extra bone in soft tissues: Abnormal bone growth in muscles or soft tissues.
• Skin breakdown: Damage to the skin from pressure or friction.
• Depression or mood changes: Emotional effects due to loss of independence or chronic discomfort.
  

The outlook for people with spasticity can vary widely, depending on factors such as the underlying cause, the severity of symptoms, the areas of the body affected, and how well the condition is managed. The impact of spasticity can also change over time, and even mild spasticity can sometimes lead to significant challenges with daily activities, hygiene, or mobility.

With appropriate treatment and support, many people with spasticity can achieve improved comfort, function, and quality of life. Regular follow-up with health care providers can help address changing needs and optimize outcomes for people living with spasticity.

Yale offers comprehensive multidisciplinary care for spasticity.

The Upper Extremity Spasticity program, led by Elspeth Hill, MBChB, PhD, combines expertise from peripheral nerve surgery, orthopedics, physiatry, and hand therapy. This multidisciplinary clinic aims to create bespoke treatment plans to meet an individual’s unique spasticity patterns and functional goals. Further, the care from pediatric to adult spasticity includes expertise from Plastic Surgery, Orthopaedics, Neurology, Therapy, Neurosurgery, and Physiatry in a collaborative approach across the Yale Health System.

This fact sheet was medically reviewed by Elspeth Hill, MBChB, PhD, a Yale Medicine plastic and reconstructive surgeon.