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Spasticity is an abnormal increase in muscle tone. It may be associated with involuntary muscle spasms , sustained muscle contractions (dystonia), and exaggerated deep tendon reflexes that make movement difficult or uncontrollable. Although it most commonly affects the legs and arms, spasticity can affect any part of the body including the trunk, neck, eyelids, face, or vocal cords.


Spastic muscles are resistant to the normal stretching that occurs during use and may remain contracted for long periods. Spasticity may not be present all the time and varies based on initial muscle tone; length of responding muscle groups; and the person's position, posture, and state of relaxation. Spasticity may increase with anxiety , emotions, pain , or sensory stimulation. It may worsen with movement of the involved muscles. Spasticity may be aggravated by temperature extremes, humidity, skin problems such as a pressure ulcer or ingrown toenail, bladder or bowel problems, infections, and sometimes tight clothing.

The severity of spasticity ranges from slight muscle stiffness to spasms that come and go, to permanent contracture. Spasticity-induced contracture can be treated with medications. If muscle contractures are not treated, fixed contracture can occur, leaving the muscle permanently shortened.

Severe spasticity can interfere with a child's normal functioning, motor and speech development, and/or comfort. Spasticity can be painful, especially if joints are pulled into abnormal positions or if range of motion is limited.

Simple activities of daily living (such as walking, eating, dressing, and bathing) may become time-consuming and difficult for both the child and caregiver. When spasticity limits activity for long periods, it can cause additional medical problems such as sleep disturbances, pressure sores, and pneumonia .


The exact incidence of spasticity is not known. Estimates report spasticity may affect over 500,000 Americans and over 12 million people world-wide.

Causes and symptoms


Spasticity occurs when certain nerve signals do not reach the muscles because of injury or disease that affects parts of the brain or spinal cord. With spasticity, muscles receive improper nerve signals, causing them to contract, while the brain is unable to communicate with the motor nerves to stop the muscles from contracting.

Common neurological conditions associated with spasticity include cerebral palsy , brain injury or trauma, severe head injury , stroke , multiple sclerosis, spinal cord injury , and some metabolic diseases.


Spasticity is characterized by increased muscle tone (hypertonicity) and by muscle stiffness.

Symptoms associated with spasticity include the following:

  • increased muscle stretch reflexes
  • involuntary contraction and relaxation of muscles (spasms)
  • prolonged muscle contractions (dystonia)
  • rapid, repetitive jerky motions (clonus)
  • exaggerated deep tendon jerks or reflexes
  • involuntary crossing of the legs (also called scissoring reflex)
  • abnormal posture or abnormal positioning of the shoulder, arm, wrist, or finger
  • increased resistance to movement of certain muscle groups

When to call the doctor

If a child has any of the following symptoms, the parent or caregiver should call the child's doctor:

  • worsening spasticity
  • apparent development of muscle contractures
  • worsening overall health


A diagnosis of spasticity is often made with the diagnosis of cerebral palsy or following a brain or spinal cord injury. A multi-disciplinary team may be consulted to provide an accurate diagnosis of spasticity so the proper treatment can be planned.

The diagnosis of spasticity includes:

  • review of personal and family medical history
  • review of current medications
  • review of other health problems
  • physical examination
  • diagnostic tests

The medical history helps the physician evaluate the presence of other conditions or disorders that might contribute to or cause the spasticity. Records of previous diagnoses, surgeries, and treatments are reviewed. The child's family medical history is evaluated to determine if there is a history of muscular or neurological disorders.

Questions about the child's medical history may include:

  • When were the symptoms first noticed?
  • How long have the symptoms lasted?
  • Are the symptoms always present?
  • What muscles are affected?
  • What makes the symptoms improve?
  • What specific treatments or techniques have been tried?
  • What makes the symptoms worse?
  • Do certain activities, emotions, or events seem to aggravate the symptoms?
  • Are other symptoms present?
  • Is the spasticity preventing function or independence?

The doctor will review the presence of other health problems such as swallowing function, bowel and bladder function, and learning difficulties.

The physical exam may include an evaluation of the child's motor reflexes including muscle tone, mobility, strength, balance and endurance; heart and lung function; cranial nerve function; and an examination of the child's abdomen, spine, throat, and ears. The child's height and weight and blood pressure also are checked and recorded.

To confirm the diagnosis of spasticity, the following tests can be performed to evaluate the child's arm and leg movements, muscular activity, range of motion, and ability to perform self-care activities:

  • x rays of the spine and hips
  • occupational and physical therapy evaluations to determine upper and lower extremity movement patterns and passive range of motion
  • diagnostic blocks with local anesthetics to provide information on the effectiveness of potential treatments
  • nerve conduction studies to evaluate muscle or nerve damage
  • electromyogram (EMG or myogram) to detect abnormal muscle electrical activity.

Nerve conduction studies and an electromyogram (EMG) are usually performed together to provide a comprehensive assessment of nerve and muscle function. In both tests, the examiner uses a computer, monitor, amplifier, loudspeaker, stimulator and high-tech filters to see and hear how the muscles and nerves are responding during the test.

In the nerve conduction study, small electrodes are placed on the skin over the muscles to be examined. A stimulator delivers a very small electrical current (that does not cause damage to the body) through the electrodes, causing the nerves to fire. In the electromyogram, a very thin, sterilized needle is inserted into various muscles, usually those affected most by spasticity symptoms. The needle is attached by wires to a recording machine. The patient is asked to relax and contract the muscles being examined. The electrical signals produced by the nerves and muscles during these tests are measured and recorded by a computer and displayed as electrical waves on the monitor. The test results are interpreted by a specially trained physician.


There is no cure for spasticity, but it can be managed with the appropriate treatment. Treatment options include physical and occupational therapy, medications, surgery, or a combination of these treatments. The goals of treatment are to increase the child's comfort, decrease pain, ease mobility, help with activities of daily living including hygiene, ease rehabilitation procedures, and prevent or decrease the risk of developing a joint contracture. The type of treatment recommended will depend upon the severity of the spasticity; the patient's overall health; the potential benefits, limitations, and side effects of the treatment; and the impact of the treatment on the child's quality of life.

In some cases, treatment is not recommended or desired, because it would actually interfere with the patient's current mobility and not improve function. For example, some people with multiple sclerosis who experience significant leg weakness find that spasticity makes their legs more rigid, helping them to stand, transfer to a chair or bed, or walk.

Clinicians should work with the child and the parents or caregivers to develop an individual treatment plan. Specific treatment goals will vary from one person to the next. Treatment should be provided by a pediatric neurologist and a multi-disciplinary team of specialists that may include a physiatrist, physical therapist, occupational therapist, gait and movement specialists, social worker, and surgical specialists as applicable, such as a pediatric orthopedic surgeon or pediatric neurosurgeon.

Physical and occupational therapy

Physical therapy includes stretching exercises, muscle group strengthening exercises, and range of motion exercises to prevent muscles from shortening (contracture), preserve flexibility and range of motion, and reduce the severity of symptoms. Exercises should be practiced daily, as recommended by the physical therapist. Prolonged stretching can lengthen muscles to help decrease spasticity. Strengthening exercises can restore the proper strength to muscles affected by spasticity. Aquatic therapy also may be recommended, since in water there is less stress on the body.

A physical therapist can instruct the patient on proper posture guidelines. Proper posture is critical, especially while sitting and sleeping, to maintain proper alignment of the hips and back. Balancing rest and exercise is also important.

Occupational therapy may include splints, casts, or braces on the affected arm or leg to enable proper limb positioning and maintain flexibility and range of motion. It may also include training for proper limb positioning while seated in a wheelchair or lying in bed.

Physical and occupational therapists can provide guidelines on how to adapt the child's environment to ensure safety and comfort.

Other treatments

Brief application (about 10 minutes) of cold packs to spastic muscles may help ease pain and improve function for a short period of time.

Electrical stimulation may be used to reduce spasticity for a short period of time or to stimulate a weak muscle to counteract the action of a stronger, spastic muscle.

Biofeedback training may be used to teach the patient how to consciously reduce muscle tension. Biofeedback uses an electrical signal that indicates when a spastic muscle relaxes. The patient may be able to use biofeedback to learn how to consciously reduce muscle tension and possibly reduce spasticity. However, little research had been conducted as of 2004 to determine the effectiveness of biofeedback on reducing spasticity.


Medications to treat spasticity are taken by mouth, injected, or received through continuous delivery systems. These medications work by preventing nerves from signaling the muscles to contract, thereby preventing muscle contractions.

If treatment with a single medicine fails to effectively treat spasticity, a different medicine may be tried or an additional medicine may be prescribed. The most important medication guidelines include making sure the child takes the medicine exactly as prescribed and not discontinuing medication without first talking to the child's doctor, even if the medication does not seem to be working or is causing unwanted side effects.

ORAL MEDICATIONS The most commonly prescribed oral medication is baclofen (Lioresal). Baclofen is a muscle relaxant that works on nerves in the spinal cord to reduce spasticity. The benefits of baclofen include decreased stretch reflexes, improved passive range of motion, and reduced muscle spasms, pain, and tightness. Side effects include drowsiness and sedation, as well as weakness, decreased muscle tone, confusion, fatigue, nausea , and dizziness . Baclofen should not be taken with central nervous system depressants or alcohol.

Benzodiazepines, such as diazepam (Valium), clonazepam (Klonopin, Rivotril), and lorazepam (Ativan) reduce spasticity by acting on the central nervous system. The benefits of benzodiazepines include improved passive range of motion, less muscle overactivity, fewer painful spasms, and overall relaxation. These medications are often taken at night because they cause drowsiness. They are also taken at night to relieve muscle spasms that interrupt sleep. Side effects include unsteadiness, loss of strength, low blood pressure, gastrointestinal symptoms, memory problems, confusion, and behavioral problems.

Datrolene sodium (Dantrium) acts on the muscles to directly interfere with the chemistry of the muscle contraction. It is generally used when other medications are not effective. Benefits may include improved passive movement, decreased muscle tone, and reduced muscle spasms, tightness, and pain. Side effects include generalized weakness, including weakness of the respiratory muscles, as well as drowsiness, fatigue, diarrhea , and sensitivity to the sun. Liver problems may occur with this medication, so frequent lab tests are performed to evaluate liver function.

Tizanidine (Zanaflex) reduces spasticity by acting on the central nervous system. It does not usually cause reduced muscle strength. The most common side effect is sedation, and other side effects include low blood pressure, dry mouth, dizziness, and hallucinations. Liver problems may occur with this medication, so frequent lab tests are performed to evaluate liver function.

INJECTED MEDICATIONS Botulinum toxin type A (Botox, Dysport) or type B (Myobloc) is injected locally into the affected muscle group to relax the muscles. It works by preventing nerves from sending signals to the muscles that cause them to contract. Although the treatment takes one to two weeks to reach its full effectiveness, the beneficial effects last three to four months. Botulinum-toxin allows more normal limb positioning and improved mobility. In some patients, the injections also decrease pain. Injections may be used to make casting easier, ease the adjustment of a new brace, or delay surgery.

Botulinum toxin is made by the bacteria that cause botulism . However, the amount of botulinum toxin injected to treat spasticity is so small that it would not cause botulism poisoning. This treatment is very safe, and the injections can be given in a doctor's office without the use of sedation or anesthesia. Injections can be repeated but should be spaced apart from three to six months to avoid exceeding the recommended dose. Botulinum-toxin injections can be used in combination with oral medications or intrathecal baclofen to treat spasticity.

Botulinum-toxin injections are typically expensive and may not be covered by insurance. A Reimbursement Hotline established by Allergan, the manufacturer of Botox, is a resource for reimbursement questions: available online at <>. Elan, the manufacturer of Myobloc, also has resources available to answer questions about reimbursement: available online at <>. Elan, the manufacturer of Myobloc, also has resources available to answer questions about reimbursement: available online at <>.

Alcohol and phenol are injected in combination but are less commonly used to treat spasticity. The medications are injected directly onto nerves that supply spastic muscles to destroy them. The injections cut off the signals to those muscles, allowing them to relax. This treatment may be used to treat spasticity in larger muscle groups closer to the trunk, such as the thigh muscles. Although this treatment is generally less expensive than botulinum-toxin injections, there are more serious side effects.

Short-term medications such as lidocaine, a local anesthetic, can be used to assess the potential benefit of botulinum toxin or alcohol and phenol injections.

CONTINUOUS DELIVERY MEDICATIONS Baclofen usually is taken as an oral medication but also can be delivered directly into the spinal fluid when the oral medication does not effectively control symptoms. An intrathecal baclofen delivery system continuously releases prescribed amounts of baclofen in small doses directly into the spinal fluid via a small catheter and pump. This type of delivery system causes fewer and less severe side effects than the oral baclofen.

To determine the potential effectiveness of the system, an initial trial of the intraspinal therapy is conducted. During this trial, the medication is delivered into the spinal fluid via a lumbar puncture procedure. The medication usually reaches its peak effectiveness within four hours. If the patient responds favorably to the trial, the intrathecal system can be considered.

The intrathecal baclofen delivery system is placed by a neurosurgeon during a surgical procedure under local or general anesthesia. First, a catheter (thin, flexible tube) is inserted through a needle and guided into the spinal canal, close to where pain pathways enter the spinal cord. The other end of the catheter is tunneled under the skin to the abdomen where a pocket is created. There, the pump is implanted under the skin (epidermal area) through an incision in the abdomen. The baclofen pump is a round, titanium disc about one inch thick and about three inches in diameter. The pump is anchored to surrounding tissue and connected to the catheter. The incision is then closed.

The pump reservoir is filled with the prescribed amount of medication. Medication can be filled and refilled in the pump by inserting a needle through the skin into a filling port (called a diaphragm) in the center of the pump.

The medication is dispensed, either continuously or at certain intervals as determined by the doctor, via a tiny motor in the pump that moves the medication from the pump reservoir through the catheter. Baclofen flows freely in the spinal canal, affecting the nerves to control hyperactive muscles. The system contains a computer chip, so adjustments to the dose, rate, and timing of the medication can be made by the physician using an external programmer. The system also has an alarm to indicate when the reservoir needs to be refilled, the battery is low, or the pump is not delivering the medication. If the system does not appear to be effective in treating spasticity, it can be turned off and eventually removed.

Pump refills and medication adjustments are generally made once every two to three months after the initial dosage is established. The pump system lasts from three to five years, at which time the system needs to be replaced.


Surgery is only recommended when all other treatments have been tried and have not effectively controlled the child's spasticity symptoms. Surgical options for chronic spasticity include selective dorsal rhizotomy and tendon release surgery.

Selective dorsal rhizotomy surgery, also called selective posterior rhizotomy, involves a surgical resection of part of the spinal nerve. By cutting the sensory nerve rootlets that cause the spasticity, muscle stiffness is decreased while other functions are maintained. Potential benefits of this surgical procedure include pain relief, reduced spasticity to improve walking or aid sitting in a wheelchair, increased ability to bend at the waist, and improved use of the hands. Sometimes, rhizotomy results in improved breathing and better control of the arms, legs, and head.

Orthopedic surgery for spasticity may be performed to correct a contracture. During contracture release surgery, the tendon of a contractured muscle is cut, the joint is repositioned to a more normal angle, and a cast is applied. Regrowth of the tendon to this new length occurs over several weeks following surgery. After the cast is removed, physical therapy can help strengthen the muscles and improve range of motion. This procedure is most commonly performed on the Achilles tendon but may also be performed on the knees, hips, shoulders, elbows, and wrists.

Tendon transfer surgery is another technique to treat contractures. During this procedure, the tendon attached to a spastic muscle is cut and transferred to a different site, preventing the muscle from being pulled into an abnormal position.

The disadvantages of these orthopedic procedures are that they are irreversible and that they may need to be repeated.

Other orthopedic surgeries that may accompany contracture release surgery include osteotomy, in which a small wedge is removed from a bone to allow repositioning. A cast is applied while the bone heals in a more natural position. Osteotomy is more commonly performed on the bones in the hips or feet. Arthrodesis is a fusing of bones that normally move independently to limit the ability of a spastic muscle to pull the joint into an abnormal position. Arthrodesis is more commonly performed on the bones in the ankle.

Nutritional concerns

Dietary guidelines are individualized, based on the child's age, diagnosis, overall health, severity of disability, and level of functioning. Specific nutritional problems, such as swallowing or feeding difficulties, may be a concern in some patients and should be managed by a team of specialists including a speech therapist. Early identification, treatment, and correction of specific feeding problems will improve the health and nutritional status of the patient.

A well-balanced and carefully planned diet will help maintain general good health for people with spasticity. Specialists recommend that people with multiple sclerosis and other movement disorders adhere to the same low-fat, high-fiber diet that is recommended for the general population.

Children with spasticity may have different energy needs, depending on their condition. One study indicated that ambulatory and non-ambulatory adolescents with cerebral palsy had decreased energy needs compared with a control group of normal adolescents. Therefore, a child's specific calorie needs should be evaluated by a registered dietitian who can work with the parents to develop an individualized meal plan. The child's weight should be obtained once a week or at least once a month to determine if caloric intake is adequate.

A child's self-feeding skills can impact his or her health outcome. One study indicated that 90 percent of children with good to fair motor and feeding skills reached adulthood. In contrast, a lack of self-feeding skills was associated with a six-fold increase in mortality (rate of death).

Maintaining a healthy weight is important to prevent the development of chronic diseases such as diabetes, high blood pressure (hypertension ), and heart disease.

Tube feedings may be required in some patients with failure to thrive , aspiration pneumonia, difficulty swallowing, or an inability to ingest adequate calories orally to maintain nutritional status or promote growth.

Alternative treatment

Alternative and complementary therapies include approaches that are considered to be outside the mainstream of traditional health care.

Techniques that reduce stress, such as yoga , Tai Chi, meditation, deep breathing exercises, guided imagery, and relaxation training, may be helpful to induce relaxation and manage spasticity. Acupuncture and biofeedback training also may help induce relaxation. Before learning or practicing any particular technique, it is important for the parent/caregiver and child to learn about the therapy, its safety and effectiveness, potential side effects, and the expertise and qualifications of the practitioner. Although some practices are beneficial, others may be harmful to certain patients.

Initial trials of cannabinoids, the active ingredient in marijuana, have shown promise in the treatment of muscle stiffness and limb straightening associated with multiple sclerosis. Further research is needed to determine the beneficial effects of marijuana-derived substances on neuromuscular symptoms associated with movement disorders. Researchers caution that smoking marijuana is dangerous, especially since there may be other harmful substances mixed in with the illegal drug.

Relaxation techniques and dietary supplements should not be used as a substitute for medical therapies prescribed by a doctor. Parents should discuss these alternative treatments with the child's doctor to determine the techniques and remedies that may be beneficial for the child.


There is no cure for spasticity, and it cannot be prevented. However, it can be well-managed with the proper combination of physical and occupational therapy, medication, and surgery. The long-term outlook for those with spasticity depends on the severity of the spasticity and the associated disorder.


Active motion (spontaneous) Motions produced by the activity of a person. Active range of motion exercises are those that are performed by the patient without assistance.

Activities of daily living (ADL) The activities performed during the course of a normal day, for example, eating, bathing, dressing, toileting, etc.

Anoxia Lack of oxygen.

Central nervous system Part of the nervous system consisting of the brain, cranial nerves, and spinal cord. The brain is the center of higher processes, such as thought and emotion and is responsible for the coordination and control of bodily activities and the interpretation of information from the senses. The cranial nerves and spinal cord link the brain to the peripheral nervous system, that is the nerves present in the rest of body.

Cerebral palsy A nonprogressive movement disability caused by abnormal development of or damage to motor control centers of the brain.

Clonic Referring to clonus, a series of muscle contractions and partial relaxations that alternate in some nervous diseases in the form of convulsive spasms.

Contraction A tightening of the uterus during pregnancy. Contractions may or may not be painful and may or may not indicate labor.

Contracture A tightening or shortening of muscles that prevents normal movement of the associated limb or other body part.

Dysphagia Difficulty in swallowing.

Dystonia Painful involuntary muscle cramps or spasms.

General anesthesia Deep sleep induced by a combination of medicines that allows surgery to be performed.

Hyperactive reflexes Reflexes that persist too long and may be too strong. For example, a hyperactive grasp reflex may cause the hand to stay clenched in a tight fist.

Hypertonia Having excessive muscular tone or strength.

Local anesthesia Pain-relieving medication used to numb an area while the patient remains awake. Also see general anesthesia.

Muscle spasm Localized muscle contraction that occurs when the brain signals the muscle to contract.

Neurologist A doctor who specializes in disorders of the nervous system, including the brain, spinal cord, and nerves.

Neurosurgeon Physician who performs surgery on the nervous system.

Occupational therapist A healthcare provider who specializes in adapting the physical environment to meet a patient's needs. An occupational therapist also assists patients and caregivers with activities of daily living and provide instructions on wheelchair use or other adaptive equipment.

Orthopedist A doctor specializing in treatment of the musculoskeletal system.

Passive movement Movement that occurs under the power of an outside source such as a clinician. There is no voluntary muscular contraction by the individual who is being passively moved.

Peripheral nerves Nerves outside the brain and spinal cord that provide the link between the body and the central nervous system.

Physiatrist A physician who specializes in physical medicine and rehabilitation.

Physical therapist A healthcare provider who teaches patients how to perform therapeutic exercises to maintain maximum mobility and range of motion.

Pressure ulcer Also known as a decubitus ulcer or bedsore, a pressure ulcer is an open wound that forms whenever prolonged pressure is applied to skin covering bony prominences of the body. Patients who are bedridden are at risk of developing pressure ulcers.

Range of motion (ROM) The range of motion of a joint from full extension to full flexion (bending) measured in degrees like a circle.

Rigidity A constant resistance to passive motion.

Scissoring Involuntary crossing of the legs.

Stroke Interruption of blood flow to a part of the brain with consequent brain damage. A stroke may be caused by a blood clot or by hemorrhage due to a burst blood vessel. Also known as a cerebrovascular accident.

Parental concerns

Parents should work closely with the child's therapists and doctors to create an effective treatment plan. It is important for parents to communicate their treatment goals with the healthcare team. Parents should take an active role in the child's exercise program and help the child practice the exercises as prescribed every day. Raising a child with a movement disorder can be challenging. There are several support groups available to provide information and assistance.



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Gelber, David A., and Douglas R. Jeffery. Clinical Evaluation and Management of Spasticity. Totowa, NJ: Humana Press Inc., 2001.


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National Institute on Disability and Rehabilitation Research, Office of Special Education and Rehabilitative Services. U.S. Department of Education, 400 Maryland Ave., SW, Washington, DC 202027100. Web site: <>.

National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health. PO Box 5801, Bethesda, MD 20824. Web site: <>.

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National Spinal Cord Injury Association. 6701 Democracy Blvd., #3009, Bethesda, MD 20817. Web site: <>.

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Angela M. Costello

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Spasticity is a form of muscle overactivity. A spastic muscle is one in which a muscle resists being stretched out, and the resistance to stretch is greater the faster the muscle is moved. Spasticity is often used as an umbrella term for other forms of muscle overactivity that often occur at the same time in the same patient.


Spasticity occurs following damage to the neurons, or nerve cells, that send signals from the brain to the muscles to cause movement. These neurons, which run from the brain through the spinal cord, are called upper motor neurons, and damage to them produces an upper motor neuron syndrome. The upper motor neuron syndrome may be caused by stroke , traumatic brain injury , spinal cord injury , multiple sclerosis , or numerous other less common causes of damage to the motor neurons. Damage to the brain occurring prior to or shortly after birth is called cerebral palsy (CP), which is the most common cause of an upper motor neuron syndrome in children.

The other forms of muscle overactivity common in the upper motor neuron syndrome are:

  • Clonus, a relatively slow rhythmic contraction and relaxation of a muscle, typically occurring after a stimulus such as movement or while attempting to hold the muscle still. Clonus can be mild or severe in intensity.
  • Spasms, strong and sustained contractions of muscles, which are often painful.
  • Increased reflexes, in which the normal reflexes (such as knee extension in response to tapping) are greatly exaggerated.

Together, all these forms of muscle overactivity can cause significant disability in a patient, interfering with dressing, bathing, feeding, mobility, and other activities of daily living. The upper motor neuron syndrome also involves weakness and loss of dexterity, which may be even more disabling to the patient, and may be much less amenable to treatment.

Clinical patterns and problems

Spasticity may affect any muscle or group of muscles, but common patterns are often seen. Each causes its own set of impairments. For instance, the forearm may be drawn up and in toward the chest, making it difficult to put on or take off a shirt. The thighs may be pulled close together, not only making dressing difficult, but narrowing the base of support for standing and walking. The fingers may be clenched tight, driving the nails into the palm and preventing access for cleaning, resulting in infections and skin breakdown. One of the most common patterns is termed equinus, in which the calf muscles tighten, preventing the ankle from flexing completely and leading to walking on the toes.

When the muscle that is overactive is also very strong, it can lead to more severe complications, including partial dislocation. Hip dislocation is a common complication of spasticity in cerebral palsy. A constant imbalance in the forces across a joint due to spasticity can cause the bone to form new tissue in response, leading to bony deformities.

Inactivity brought on by disability can lead to a host of other problems, including pressure sores, osteoporosis, respiratory infections, and social isolation.


The resistance to stretch that characterizes spasticity may be mild and infrequent, or it may be severe and quite frequent. In the latter case, the patient can rarely attain a fully stretched position for the muscle, and the muscle spends more time than normal in a partially shortened position. When this occurs, a muscle can develop contracture. A contracture is the loss of full range of motion of a joint due to changes in the soft tissues (muscles and tendons) surrounding that joint. In contracture, the muscle fibers remodel themselves to accommodate this shorter length, thus shortening the muscle overall. In addition, the muscle may develop more fibrous tissue that cannot stretch as much, further increasing its resistance to stretch.

A muscle that develops contracture becomes almost impossible to stretch out to its full length, further worsening the clinical problems of the person with spasticity.


Spasticity or other forms of muscle overactivity should be treated if they interfere with function, comfort, or care, or have the potential to lead to deformity that will later require treatment. Treatments available include physical therapy, oral medications, chemical denervation, intrathecal baclofen, neurosurgery, and orthopedic surgery.

Physical therapy

Physical therapy includes daily stretching exercises to maintain the full range of motion for the affected muscles. In mild spasticity, this may be the only treatment needed, while in severe spasticity, it is a part of the full therapy plan. Physical therapy also includes instructions in how to perform activities that are energy-efficient and do not worsen spasticity, including ways to transfer in and out of bed, sitting positions, and hygiene activities.

Bracing may be used to support a weak muscle, or to prevent excess contraction of a spastic muscle. A knee-ankle-foot brace is common to help correct equinus, for instance. Serial casting may be used to stretch out a contractured muscle, with a series of casts at increasing joint angles applied over time. The physical therapist also provides advice on assistive equipment such as wheelchairs and walkers.

Oral medications

Four main medications are used to treat spasticity and other forms of muscle overactivity. Each causes sedation, and thus their uses are limited in patients for whom excess sedation is a significant problem. Oral medications are typically most useful in patients with mild, widespread spasticity, or those for whom sedation is not a problem. They may also be useful at night, to improve comfort during sleep.

Benzodiazepines include diazepam and clonazepam. They are most commonly used in spinal cord injury and multiple sclerosis, and may be especially effective against painful spasms. They also reduce anxiety, which may be useful in some patients. Typical side effects include weakness, sedation, and confusion.

Oral baclofen is primarily used for patients with spinal cord injury or multiple sclerosis (MS). A special caution with baclofen is that sudden withdrawal may cause seizures and hallucinations. Tizanidine is also used widely in those with spinal cord injury or MS, and is also used in other patients. It is less likely to cause weakness than some other oral medications.

Dantrolene sodium is used for patients with stroke, cerebral palsy, MS, and spinal cord injury. It is somewhat less likely to cause confusion and sedation than other medications, and may be more effective against clonus than some of the other medications. Diarrhea is a side effect in some patients, and monitoring for liver damage is required.


Chemodenervation refers to use of a chemical to prevent a nerve from stimulating its target muscle. This reduces spasticity. Chemodenervation is performed with phenol, ethyl alcohol, or botulinum toxin . Chemodenervation is most appropriate in patients with localized spasticity in one or two large muscles or several small muscles.

Phenol and ethyl alcohol are injected directly onto the nerve, causing the nerve fiber to degenerate so that it cannot send messages to the muscle. Benefits may last from a month to six months or more, when the nerve regrows. Advantages of the procedure are that the chemicals are inexpensive and can be used repeatedly. Disadvantages are that the injection requires a high degree of skill, may cause pain due to damage to nerves carrying sensory information, and has a somewhat unpredictable duration of action.

Botulinum toxin is injected into the overactive muscle. It prevents the nerve endings from releasing the chemical they use to stimulate the muscle. The effect lasts approximately three months. Benefits include a simpler and easier injection procedure, with more predictable and reproducible results, with no risk of pain. Disadvantages include high cost and the potential to develop antibodies against the toxin after repeat injections, rendering it ineffective.

Intrathecal baclofen

Intrathecal baclofen (ITB) delivers baclofen directly to the spinal cord, via a tube from an implanted pump. It is most commonly used in patients with widespread spasticity, especially children with cerebral palsy. The pump is implanted in the wall of the abdomen, and the tube is inserted between the vertebrae in the lower or mid-back, releasing the drug into the space surrounding the spinal cord. This allows a much smaller amount of baclofen to be used than if delivered orally, reducing side effects. The baclofen is contained in a reservoir within the pump, and is refilled approximately every three months. The dose can be adjusted to match activities, for instance, increasing at night to aid sleep and decreasing in the morning to increase stiffness slightly to aid getting out of bed. Risks include pump failure and sudden withdrawal from baclofen, which can be dangerous or even fatal, as well as surgery and anesthesia risks. Benefits include reduced spasticity without excess sedation.


Selective dorsal rhizotomy (SDR) is used to treat spasticity in cerebral palsy. During SDR, certain overactive nerves entering the spinal cord are cut, reducing the activity that leads to spasticity. Children receiving SDR tend to be able to walk more normally, assuming they have good underlying strength before the operation. SDR is a major surgery requiring general anesthesia. Long-term results indicate children receiving SDR require slightly fewer orthopedic surgeries later in life.

Orthopedic surgery

This type of surgery is performed on muscle or bone, in order to correct deformity, including contracture. The most common surgery is tendon lengthening to treat equinus. In this procedure, the Achilles tendon is cut and the leg is placed in a cast in a more normal position. The tendon regrows to a longer length, reducing the equinus. Other tendon lengthening procedures are performed at the hips and knees. An osteotomy may also be performed to remove abnormal bone growth.



Glenn, J. Whyte. The Practical Management of Spasticity. Philadelphia: Lea & Febiger, 1990.

Mayer, N. H., and D. M. Simpson. Spasticity: Etiology, Evaluation, Management, and the Role of Botulinum Toxin. New York: WE MOVE, 2002.


WE MOVE. 204 West 84th Street, New York, NY 10024. (212) 875-8389 or (800) 437-MOV2. <>.

Richard Robinson

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"Spasticity." Gale Encyclopedia of Neurological Disorders. . 12 Dec. 2017 <>.

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spasticity is an abnormal physiological state of increased muscle tone with exaggeration of the tendon jerks or reflexes. The definition implies comparison with normal muscle tone, and therein lies the importance of clinical experience. Physicians use their own ‘proprioceptive’ sense to assess whether muscular tone is normal, by slowly moving the patient's limbs at the knee, ankle, and wrist joints so as to stretch the muscles acting on them — the quadriceps at the knee for example, and the biceps at the elbow. The slight resistance to movement in a normal subject is attributable to the intrinsic, passive mechanical properties of the muscles, tendons, joints, and ligaments, because in a resting and, equally important, relaxed subject, there is no muscle activity to generate an opposing force. However, in a spastic limb, for all but the very slowest of joint movements the physician perceives an opposing resistance to movement, the immediate cause of which is an exaggerated ‘stretch’ reflex. This spinal reflex, which arises in muscle receptors exquisitely sensitive to muscle stretch, is notable for the fact that the relevant afferent fibres pass directly to the motor neurons innervating the same and closely related (agonist) muscles. Thus, when muscle tone is enhanced, so also are the tendon jerks; if the patellar or other tendons are tapped, which applies a brief stretch to the muscles, the reflex jerk is larger or more ‘brisk’ than usual. Indeed, brisk jerks may be the earliest indication of a developing spasticity.

Spasticity results from loss of the control of the spinal reflex centres that normally descends from higher parts of the central nervous system, via several different nerve pathways. Thus, for example, a stroke can interrupt the pathway descending from the cerebral cortex, resulting in spasticity of the limbs on the affected side of the body; or a complete transection of the spinal cord can leave the reflex centres for both legs uncontrolled, so that they become spastic (after recovery from an initial period of ‘spinal shock’). The importance of such descending control over the reflex pathways within the spinal cord has been known for many years. However, the fine detail concerning the many different types of interneuron that subserve such control has only been established over the last 20–30 years through experiments on anaesthetized animals. From these, new concepts have emerged which in turn have led to the development of sophisticated, electrophysiolgical measurements for use in man. These will be important in establishing the usefulness of the concepts in the search for symptomatic therapies that might ease the mobility problems resulting from spasticity. Meanwhile, direct recording in man of the electrical activity of the muscle receptors, using the technique of microneuronography, in which ultra-fine electrodes are inserted into the relevant peripheral nerves, has proved to be a valuable technique. It has been established, with respect to the muscle nerves so far examined, that spasticity is not due to an exaggerated sensitivity of the muscle receptors (‘spindles’) to stretch. This factor had preoccupied much of the thinking about the cause of spasticity since the early 1950s, following the discovery that the sensitivity of muscle spindles depends on central nervous system control over the ‘gamma’ motor neurons that innervate the special types of muscle fibre within the muscle spindles.

Tom Sears

See also cerebral palsy; muscle tone; paralysis; reflexes; stroke.

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"spasticity." The Oxford Companion to the Body. . 12 Dec. 2017 <>.

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spasticity (clasp-knife rigidity) (spas-tis-iti) n. resistance to the passive movement of a limb that is maximal at the beginning of the movement and gives way as more pressure is applied. It is a symptom of damage to the corticospinal (pyramidal) tracts in the brain or spinal cord. Compare rigidity.

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"spasticity." A Dictionary of Nursing. . 12 Dec. 2017 <>.

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