Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures or dislocates your vertebrae, the bone disks that make up your spine. Most injuries don't cut through your spinal cord. Instead, they cause damage when pieces of vertebrae tear into cord tissue or press down on the nerve parts that carry signals.

Spinal cord injuries can be complete or incomplete. With a complete spinal cord injury, the cord can't send signals below the level of the injury. As a result, you are paralyzed below the injury. With an incomplete injury, you have some movement and sensation below the injury.

A spinal cord injury is a medical emergency. Immediate treatment can reduce long-term effects. Treatments may include medicines, braces or traction to stabilize the spine, and surgery. Later treatment usually includes medicines and rehabilitation therapy. Mobility aids and assistive devices may help you to get around and do some daily tasks.

A spinal cord injury (SCI) is damage to the tight bundle of cells and nerves that sends and receives signals from the brain to and from the rest of the body. The spinal cord extends from the lower part of the brain down through the lower back.

SCI can be caused by direct injury to the spinal cord itself or from damage to the tissue and bones (vertebrae) that surround the spinal cord. This damage can result in temporary or permanent changes in sensation, movement, strength, and body functions below the site of injury.

Injury and severity

The extent of disability depends on where along the spinal cord the injury occurs and the severity of the injury.

Loss of nerve function occurs below the level of injury. An injury higher on the spinal cord can cause paralysis in most of the body and affect all limbs (called tetraplegia or quadriplegia). A lower injury to the spinal cord may cause paralysis affecting the legs and lower body (called paraplegia).

A spinal cord injury can damage a few, many, or almost all of the nerve fibers that cross the site of injury. A variety of cells located in and around the injury site may also die. Some injuries having little or no nerve cell death may allow an almost complete recovery.

Type of injury

A spinal cord injury can be classified as complete or incomplete.

• An incomplete injury means the spinal cord is still able to transmit some messages to or from the brain. People with incomplete injuries retain some sensory function and may have some control of muscle activity below the injury site.
• A complete injurymeans there is no nerve communications and sensory and motor function below the injury site are lost.

Primary damage is immediate and is caused directly by the injury. Secondary damage results from inflammation and swelling that can press on the spinal cord and vertebrae, as well as from changes in the activity of cells and cell death.

Common causes

Motor vehicle accidents and catastrophic falls are the most common causes of SCI in the United States. The rest are due to acts of violence (primarily gunshot wounds and assaults), sports injuries, medical or surgical injury, industrial accidents, diseases and conditions that can damage the spinal cord, and other less common causes.

The spinal cord is a soft, cylindrical column of tightly bundled nerve cells (neurons and glia), nerve fibers that transmit nerve signals (called axons), and blood vessels. It sends and receives information between the brain and the rest of the body. Millions of nerve cells situated in the spinal cord itself also coordinate complex patterns of movements such as rhythmic breathing and walking.

The spinal cord extends from the brain to the lower back through a canal in the center of the bones of the spine. Like the brain, the spinal cord is protected by three layers of tissue and is surrounded by the cerebrospinal fluid that acts as a cushion against shock or injury.

Inside the spinal cord is:

• A collection of neurons and their projections that connect with other nerve cells to transmit and receive information, called gray matter.
• Bundles of axons, some of which are coated with a whitish mixture of proteins and fat-like substances, called white matter.

Other types of nerve cells sit just outside the spinal cord and relay information to the brain.

31 pairs of nerves, each of which contains thousands of axons, are divided into 4 regions having individual segments and link the spinal cord to muscles and other parts of the body:

• Cervical spinal nerves (C1 to C8) emerge from the spinal cord in the neck and control signals to the back of the head, the neck and shoulders, the arms and hands, and the diaphragm.
• Thoracic spinal nerves (T1 to T12) emerge from the spinal cord in the upper mid-back and control signals to the chest muscles, some muscles of the back, and many organ systems, including parts of the abdomen.
• Lumbar spinal nerves (L1 to L5) emerge from the spinal cord in the low back and control signals to the lower parts of the abdomen and the back, the buttocks, some parts of the external genital organs, and parts of the leg.
• Sacral spinal nerves (S1 to S5) emerge from the spinal cord in the low back and control signals to the thighs and lower parts of the legs, the feet, most of the external genital organs, and the area around the anus.

The spinal column, which surrounds and protects the spinal cord, is made up of 33 rings of bone (called vertebrae), pads of semi-rigid cartilage (called discs), and narrow spaces called foramen that act as passages for spinal nerves to travel to and from the rest of the body. These are places where the spinal cord is particularly vulnerable to direct injury.

According to the National SCI Statistical Center, annually there are about 12,000 new cases of SCIs in the United States, which amounts to about 40 cases per million people. The last studies of the incidence of SCI were conducted in the 1990s, however, and so it is not known whether incidence has changed in recent years. In 2010, about a quarter of a million people in the United States were living with an SCI.

The majority of SCIs occur in young to middle-aged adults. From 1973 to 1979, the average age at injury was 28.7 years, and most injuries occurred between the ages of 16 and 30. However, demographic changes since the mid-1970s have resulted in an increase of 9 years in the median age of the U.S. population. Similarly, the average age for an SCI has increased over time. From 2005 to 2010, the average age was 40.7.

Who is at risk for SCI?

SCIs are typically the result of accidents and therefore can happen to anyone.

Factors that increase the risk of SCI:

• Driving or riding in a car. Using a seatbelt can reduce the possibility of an SCI by 60%; using a seatbelt plus having a functioning airbag can cut the odds of this injury by 80%.
• Being male. 80% of spinal cord injury patients are male.
• Operating machinery without using safety equipment
• Improper or unsafe use of a ladder, which can result in a fall from the ladder
• Using drugs or alcohol while driving, operating machinery, or playing sports
• Having arthritis, osteoporosis, or another bone or joint disorder

SCIs result from damage to the vertebrae, ligaments, or disks of the spinal column or to the spinal cord itself.

A traumatic SCI may stem from a sudden blow to the spine that fractures, dislocates, crushes, or compresses one or more vertebrae. Car crashes are the leading cause of SCI among people younger than 65. Falls cause most SCIs in persons age 65 and older.

Since 2005, SCI has been caused by:

• Car crashes (40.4%)
• Falls (27.9%)
• Violence, including gunshot wounds (15%)
• Sport-related accidents (8%)
• Other/unknown (8.5%)

What happens in your body when your spinal cord is injured?

When an SCI occurs, the spinal cord starts to swell at the damaged area, cutting off the vital blood supply to the nerve tissue and starving it of oxygen. This sets off a cascade of devastation that affects the entire body, causing the injured spinal tissue to die, be stripped of its insulation, and be further damaged by a massive response of the immune system.

• Blood flow. The sluggish blood flow at the injury site begins to reduce the flow of blood in adjacent areas, which soon affects all areas of the body. The body begins to lose the ability to self-regulate, leading to drastic drops in blood pressure and heart rate.
• Flood of neurotransmitters. The SCI leads to an excessive release of neurotransmitters, or biochemicals that let nerve cells communicate with each other. These chemicals, especially glutamate, overexcite nerve cells, killing them through a process known as excitotoxicity. The process also kills the vital oligodendrocytes that surround and protect the spinal axons with the myelin insulation that allows the spinal nerves to transmit information to and from the brain.
• Invasion of immune cells. An army of cells of the immune system speeds to the damaged area of the spine. While they help by preventing infection and cleaning up dead cellular debris, they also promote inflammation. These immune cells stimulate the release of certain cytokines that, in high concentrations, can be toxic to nerve cells, especially those needed to maintain the myelin sheath around axons.
• Onslaught of free radicals. The inflammation caused by cells in the immune system unleashes waves of free radicals, which are highly reactive forms of oxygen molecules. These free radicals react destructively with many types of cellular molecules, in the process severely damaging healthy nerve cells.
• Nerve cell self-destruction. A normally natural process of programmed cell death, known as apoptosis, goes out of control at the injury site. The reasons are not known. Days or weeks after the injury, oligodendrocytes die from no apparent cause, reducing the integrity of the spinal cord.

Additional damage usually occurs over the days or weeks following the initial injury because of bleeding, swelling, inflammation, and accumulation of fluid in and around the spinal cord.

According to the American Association of Neurological Surgeons, there are many different symptoms or signs of SCI. Some of the more common signs of SCI include:

• Extreme pain or pressure in the neck, head, or back
• Tingling or loss of sensation in the hand, fingers, feet, or toes
• Partial or complete loss of control over any part of the body
• Urinary or bowel urgency, incontinence, or retention
• Difficulty with balance and walking
• Abnormal band-like sensations in the thorax—pain, pressure
• Impaired breathing after injury
• Unusual lumps on the head or spine

SCI is associated with many secondary conditions that have significant impacts on medical rehabilitation management, long-term outcome, and quality of life.

• Secondary conditions associated with SCIs include:
  • Breathing problems
  • Bowel and bladder problems, including overactive bladder and incontinence
  • Heart problems
  • Pressure sores
  • Sexual function problems
  • Pain
  • Blood clots
  • Impaired muscle coordination (or spasticity)
  • Pneumonia
  • Autonomic dysreflexia (or hyperreflexia), which causes a potentially lethal increase in blood pressure
  • Increased likelihood of certain cancers, including bladder cancer

While the number of cases of SCI in children and adolescents is not high relative to other age groups, their medical outcomes may be more negatively affected by an SCI. Few studies performed to date have examined SCI in children and adolescents and many questions remain unanswered. Some of these questions include how having an SCI affects the growth and development of children and adolescents. For example, as young people grow, their bones and bodies grow with them; however, this growth may be altered in children and adolescents with an SCI. In addition, because the trunk support system is less developed in a child compared to an adult, a child with an SCI may have more frequent secondary conditions (e.g., respiratory and bowel/bladder problems). Also, children and adolescents may have a higher risk for a secondary skeletal condition because of skeletal immaturity.

After an SCI, many of the body's functions may change dramatically. The following issues may arise:

• Bone loss
• Obesity
• Muscle atrophy
• Pressure ulcers
• Bladder/bowel disorders
• Cardiovascular problems
• Changes in sexual and reproductive functions
• Pain
• Depression and adjustment to illness

In recent decades, individuals with an SCI have been gaining longer life spans and the importance of understanding the impact of aging on the above issues has become increasingly evident.

SCIs are not always immediately recognizable. The following injuries should be assessed for possible damage to the spinal cord:

• Head injuries, particularly those with trauma to the face
• Pelvic fractures
• Penetrating injuries in the area of the spine
• Injuries from falling from heights

If any of these injuries occur together with any of the symptoms mentioned above (acute head, neck, or back pain; decline of feeling in the extremities; loss of control over part of the body; urinary or bowel problems; walking difficulty; pain or pressure bands in the chest area; difficulty breathing; head or spine lumps), then SCI may be implicated.

A person suspected of having an SCI must be carefully transported—to prevent further injury the spine should be kept immobile—to an emergency room or trauma center. A doctor will question the person to determine the nature of the accident, and the medical staff may test the patient for sensory function and movement. If the injured person complains of neck pain, is not fully awake, or has obvious signs of weakness or neurological injury, diagnostic tests will be performed.

These tests may include:

• A CT ("cat") scan. This approach uses computers to form a series of cross-sectional images that may show the location and extent of the damage and reveal problems such as blood clots (hematomas).
• An MRI (magnetic resonance imaging) scan. An MRI machine "takes a picture" of the injured area using a strong magnetic field and radio waves. A computer creates an image of the spine to reveal herniated disks and other abnormalities.
• A myelogram. This is an X-ray of the spine taken after a dye is injected.
• Somatosensory evoked potential (SSEP) testing or magnetic stimulation. Performing these tests may show if nerve signals can pass through the spinal cord.
• Spine X-rays. These may show fracture or damage to the bones of the spine.

On about the third day after the injury, doctors give patients a complete neurological examination to diagnose the severity of the injury and predict the likely extent of recovery. This involves testing the patient's muscle strength and ability to sense light touch and a pinprick. Doctors use the standard ASIA (American Spinal Injury Association) Impairment Scale for this diagnosis. X-rays, MRIs, or more advanced imaging techniques are also used to visualize the entire length of the spine.

The ASIA Impairment Scale has five classification levels, ranging from complete loss of neural function in the affected area to completely normal:

• A: The impairment is complete. There is no motor or sensory function left below the level of injury.
• B: The impairment is incomplete. Sensory function, but not motor function, is preserved below the neurologic level (the first normal level above the level of injury) and some sensation is preserved in the sacral segments S4 and S5.
• C: The impairment is incomplete. Motor function is preserved below the neurologic level, but more than half of the key muscles below the neurologic level have a muscle grade less than 3 (i.e., they are not strong enough to move against gravity).
• D: The impairment is incomplete. Motor function is preserved below the neurologic level, and at least half of the key muscles below the neurologic level have a muscle grade of 3 or more (i.e., the joints can be moved against gravity).
• E: The patient's functions are normal. All motor and sensory functions are unhindered.

To illustrate, a person classified as C-level on the ASIA scale functions better than a person at the B level. Time was, a patient might have been labeled a C4 quadriplegic. Today, however, using the ASIA scale, the classification might be C4 ASIA A tetraplegic. Regarding muscle-strength grades, zero is the lowest, corresponding to complete absence of muscle movement. Five is the highest, representing full, normal strength.

Unfortunately, there are at present no known ways to reverse damage to the spinal cord. However, researchers are continually working on new treatments, including prostheses and medications, which may promote regeneration of nerve cells or improve the function of the nerves that remain after an SCI.

SCI treatment currently focuses on preventing further injury and empowering people with an SCI to return to an active and productive life.

At the Scene of the Incident

Quick medical attention is critical to minimizing the effects of head, neck, or back trauma. Therefore, treatment for an SCI often begins at the scene of the injury.

Emergency personnel typically:

• Immobilize the spine as gently and quickly as possible using a rigid neck collar and a rigid carrying board
• Use the carrying board to transport the patient to the hospital

In the Emergency Room

Once the patient is at the hospital, health care providers focus on:

• Maintaining the person's ability to breathe
• Immobilizing the neck to prevent further spinal cord damage

Health care providers also may treat an acute injury with:

• Surgery. Doctors may use surgery to remove fluid or tissue that presses on thespinal cord (decompression laminectomy); remove bone fragments, disk fragments, or foreign objects; fuse broken spinal bones; or place spinal braces.
• Traction. This technique stabilizes the spine and brings it into proper alignment.
• Methylprednisolone (Medrol). If this steroid medication is administered within 8 hours of injury, some patients experience improvement. It appears to work by reducing damage to nerve cells and decreasing inflammation near the site of injury.
• Experimental treatments. Scientists are pursuing research on how to halt cell death, control inflammation, and promote the repair or regeneration of nerves. See "Is there a cure for SCI?"

People with SCI may benefit from rehabilitation, including:

• Physical therapy geared toward muscle strengthening, communication, and mobility
• Use of assistive devices such as wheelchairs, walkers, and leg braces
• Use of adaptive devices for communication
• Occupational therapy focused on fine motor skills
• Techniques for self-grooming and bladder and bowel management
• Coping strategies for dealing with spasticity and pain
• Vocational therapy to help people get back to work with the use of assistive devices, if needed
• Recreational therapy such as sports and social activities
• Improved strategies for exercise and healthy diets (obesity and diabetes are potential risk factors for persons with SCI)
• Functional electrical stimulation for assistance with restoration of neuromuscular function, sensory function, or autonomic function (e.g., bladder, bowel, or respiratory function).

Immediate (acute) treatment

At the accident scene, emergency personnel will put a rigid collar around the neck and carefully place the person on a rigid backboard to prevent further damage to the spinal cord. Sometimes the person may be sedated to relax and prevent movement. A breathing tube may be inserted if the person has problems breathing and the body isn’t receiving enough oxygen from the lungs.

Immediate treatment at the trauma center may include:

• Realigning the spine using a rigid brace or mechanical force, which is usually done as soon as possible to stabilize the spine and prevent additional damage.
• Surgery to remove any fractured vertebrae, bone fragments, herniated discs, or other objects that are pressing on the spinal column. Spinal decompression surgery to relieve pressure within the spinal column also may be necessary in the days after injury. Results of a neurosurgical study show that, in some cases, earlier surgery is associated with better functional recovery.

Possible Complications of SCI and treatment

• Breathing. About one-third of those with a neck injury will need temporary or permanent help with breathing and may require an inserted artificial breathing tube. Any injury to the spinal cord between the C1-C4 segments (see Appendix) can stop breathing, as the nerves in this region cause the diaphragm to move and the lungs to expand. Special training regarding breathing and swallowing may be needed.
• Pneumonia. Respiratory complications are the leading cause of death in people with SCI, commonly as a result of pneumonia. People who have an inserted breathing tube and are placed on a ventilator to assist with breathing (called intubation) are at increased risk of developing pneumonia. They must be carefully monitored and treated with antibiotics if symptoms of pneumonia appear. Clearing secretions from the throat and preventing food and liquids from being sucked into the lungs (called aspiration) can prevent pneumonia.
• Circulatory problems. Changes in circulation, including blood pressure instability, abnormal heart rhythms (arrhythmias), and blood clots may appear days after the injury. Blood pressure needs to be closely monitored to keep blood and oxygen flowing through the spinal cord tissue. Because the brain’s control of the cardiac nerves can be cut off, the heart can beat at a dangerously slow pace, or it can pound rapidly and irregularly. Changes in the control of blood vessels can cause them to widen and allow blood to pool in the small arteries far away from the heart. People with spinal cord injuries are at increased risk for blood clots due to stagnation of blood flow in the large veins in the legs. Treatment includes anticoagulant drugs and compression stockings to increase blood flow in the lower legs and feet.
• Spasticity and muscle tone. Reflexes may become exaggerated over time, causing muscle spasticity that may require special treatment. Muscles may waste away due to underuse.
• Autonomic dysreflexia. Autonomic dysreflexia is a life-threatening reflex action that primarily affects those with injuries to the neck or upper back. Symptoms may include flushing or sweating, a pounding headache, anxiety, sudden increase in blood pressure, vision changes, or goose bumps on the arms and legs. If possible, the person should be kept in a sitting position, rather than lying flat, to keep blood flowing to the legs and feet and help reduce blood pressure.
• Pressure sores (or pressure ulcers). Pressure sores are areas of skin that have broken down because of continuous pressure on the skin and reduced blood flow to the area. People with paraplegia and tetraplegia are susceptible to pressure sores because they may lose all or part of skin sensations and cannot shift their weight. As a result, individuals must be shifted periodically by a caregiver if they cannot shift positions themselves. Special motorized rotating beds may be used to prevent and treat sores.
• Pain. Some people who have spinal cord nerve damage develop neurogenic pain—pain or an intense burning or stinging sensation that may be constant due to extreme physical sensitivity (called hypersensitivity) in some parts of the body. It can either be spontaneous or triggered by a variety of factors and can occur even in parts of the body that have lost normal sensation. Treatments for chronic pain include medications, acupuncture, spinal or brain electrical stimulation, and surgery. However, none of these treatments are completely effective at relieving neurogenic pain.
• Bladder and bowel problems. Some people may need to use a catheter to empty their bladder or learn ways to empty their bowels. A change in diet may be needed to help with control.
• Sexual function. Depending on the level of injury and recovery from the trauma, sexual function and fertility may be affected. A urologist and other specialists can suggest different options for sexual functioning and health.
• Depression. Many people living with a spinal cord injury may develop depression due to lifestyle changes. Therapy and medicine may help treat depression.

Once someone has survived the injury and begins to cope psychologically and emotionally, the next concern is how to live with disabilities. Doctors are now able to predict with reasonable accuracy the likely long-term outcome of spinal cord injuries. This helps people experiencing SCI set achievable goals for themselves and gives families and loved ones a realistic set of expectations for the future.

Rehabilitation

Rehabilitation programs combine physical therapies with skill-building activities and counseling to provide social and emotional support, as well as to increase independence and quality of life.

A rehabilitation team is usually led by a doctor specializing in physical medicine and rehabilitation (called a physiatrist) and often includes social workers, physical and occupational therapists, recreational therapists, rehabilitation nurses, rehabilitation psychologists, vocational counselors, nutritionists, a case worker, and other specialists.

In the initial phase of rehabilitation, therapists emphasize regaining communication skills and leg and arm strength. For some individuals, mobility will only be possible with assistive devices such as a walker, leg braces, or a wheelchair. Communication skills such as writing, typing, and using the telephone may also require adaptive devices for some people with tetraplegia.

• Physical therapy includes exercise programs geared toward strengthening muscles.
• Occupational therapy helps redevelop fine motor skills, particularly those needed to perform activities of daily living such as getting in and out of a bed, self-grooming, eating, and using a toilet. People may learn how to cope with spasticity, autonomic dysreflexia, and neurogenic pain.
• Vocational rehabilitation includes identifying basic work skills and physical and cognitive capabilities to determine the likelihood for employment; identifying potential workplaces and any assistive equipment that will be needed; and arranging for a user-friendly workplace.
• Educational training can help people develop skills for a new line of work that may be less dependent upon physical abilities and more dependent upon computer or communication skills. People with SCI or other disabilities are encouraged to participate in activities that provide a sense of satisfaction and self-esteem, such as educational classes, hobbies, joining special interest groups, and participating in family and community events.
• Recreation therapy encourages people with SCI to participate in sports or activities at their level of mobility, as well as achieve a more balanced and normal lifestyle that provides opportunities for socialization and self-expression.

Adaptive devices also may help people with spinal cord injury to regain independence and improve mobility and quality of life. Such devices may include a wheelchair, electronic stimulators, assisted training with walking, neural prostheses (assistive devices that may stimulate the nerves to restore lost functions), computer adaptations, and other computer-assisted technology.

There is no known cure for the loss of nerve tissue associated with an SCI. However, depending on the extent of damage to the spinal tissue, partial or almost complete recovery may occur for some people from 1 week to 6 months after an injury. Other people may experience small improvements for up to 1 year or even longer.

The major developments in the treatment of SCI have been in the areas of rehabilitation and improvement in quality of life. Even though SCI may disrupt one's life, those who have experienced this injury can be taught how to use mechanical and technological devices to provide more independence in terms of mobility, working, interacting with their families, and recreation. Additional help can be provided to help people with SCIs manage emotional and sexual issues.

Research is ongoing to treat the various symptoms and problems associated with SCI and to develop therapies that promote the regeneration of nerves. The National Institute of Neurological Disorders and Stroke supports research to help people with SCI, as do other institutions, including the NICHD. This includes research on the four principals of spinal cord repair:

• Protecting surviving nerve cells from further damage
• Replacing damaged nerve cells
• Stimulating the regrowth of axons and targeting their connections appropriately
• Retraining neural circuits to restore body functions

Paralysis can completely change a person's life. It can be depressing, frightening, and daunting at first to consider how to reengage with previous activities and relationships, such as those involving family, employment, friendships, and recreation/exercise. Even so, a patient with an SCI can develop strong motivation and a good support system for recovery and enjoy a fulfilling and happy life.

Scientists continue to investigate new ways to better understand and treat spinal cord injuries.

Much of this research is conducted or funded by the National Institute of Neurological Disorders and Stroke (NINDS). NINDS is a component of the National Institutes of Health (NIH), the leading supporter of biomedical research in the world. Other NIH components, as well as the Department of Veterans Affairs, other Federal agencies, research institutions, and voluntary health organizations, also fund and conduct basic to clinical research related to improvement of function in paralyzed individuals.

The Brain Research through Advancing Innovative Technologies® (BRAIN) Initiative brings together multiple federal agencies and private organizations to develop and apply new technologies to understand how complex circuits of nerve cells enable thinking, movement control, and perception. Research funded as part of the BRAIN Initiative that has the potential to improve the outlook for SCI includes:

• Looking at brain circuits to better understand the sensory and motor basis of behavior.
• Next-generation neural prostheses (devices that connect to the nervous system and restore functions lost due to disease or injury).
• Improved brain and spinal cord imaging.
• New brain-computer interface devices.

Basic spinal cord function research studies how the normal spinal cord develops, processes sensory information, controls movement, and generates rhythmic patterns (like walking and breathing). Basic studies using cells and animal models provide an essential foundation for developing interventions for spinal cord injury.

Research on injury mechanisms focuses on what causes immediate harm and on the cascade of helpful and harmful bodily reactions that protect from or contribute to damage in the hours and days following a spinal cord injury. This includes testing of neuroprotective interventions in laboratory animals.

Current research on SCI is focused on advancing our understanding of four key principles of spinal cord repair:

• Neuroprotection—preventing cell death and protecting surviving nerve cells from further damage, such as drugs to reduce nerve cell death and controlled lowering of the body’s core temperature to reduce cell and blood vessel damage and improve functional outcome.
• Repair and regeneration—encouraging the spinal cord’s intrinsic ability to self-repair and stimulating the regrowth of nerve cell projections (axons) and targeting their connections appropriately, including cell transplants, natural growth-promoting substances, and bioengineered growth scaffolds that allow axons to bridge across the injury site and rebuild neural circuits.
• Cell-based therapies—replacing damaged nerve or support cells with other cell types, including stem cells, to regenerate neuronal growth and create new cell connections.
• Retraining central nervous system circuits to restore body functions and form new nerve connections and pathways following injury or cell death (called neuroplasticity) through techniques including rehabilitation, electrical stimulation, robot-assisted training, and brain-computer interface technology that may help with voluntary muscle movement and coordination.

Neural engineering strategies build on decades of pioneering NINDS investment that established the field of neural prostheses. For example, researchers are developing a networked functional electrical stimulation system to restore independence through combined implants for hand function, postural control, and bowel and bladder control. NINDS has also led development of experimental brain computer interfaces that enable people to control a computer cursor or robotic arm directly from their brains.