Spinal cord injury

1.       What is spinal cord injury

A spinal cord injury usually begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. The damage begins at the moment of injury when displaced bone fragments, disc material, or ligaments bruise or tear into spinal cord tissue. Most injuries to the spinal cord don't completely sever it. Instead, an injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy the axons, extensions of nerve cells that carry signals up and down the spinal cord between the brain and the rest of the body. An injury to the spinal cord can damage a few, many, or almost all of these axons. Some injuries will allow almost complete recovery. Others will result in complete paralysis.

2.       What is the spinal cord and the vertebra?

a)       The spinal cord is about 18 inches in length and extends from the base of the brain, surrounded by the vertebral bodies, down the middle of the back, to about the waist. The nerves that are situated within the spinal cord are called upper motor neurons (UMNs) and their function is to carry the messages back and forth from the brain to the spinal nerves along the spinal tract.  The spinal nerves that branch out from the spinal cord to the other parts of the body are called lower motor neurons (LMNs). These spinal nerves exit and enter at each vertebral level and communicate with specific areas of the body. The sensory portions of the LMN carry messages about sensation from the skin such as pain and temperature, and other body parts and organs to the brain. The motor portions of the LMN send messages from the brain to the various body parts to initiate actions such as muscle movement.

b)       The spinal cord is the major bundle of nerves that carry nerve impulses to and from the brain to the rest of the body. The brain and the spinal cord constitute the Central Nervous System. Motor and sensory nerves outside the central nervous system constitute the Peripheral Nervous System, and another diffuse system of nerves that control involuntary functions such as blood pressure and temperature regulation are the Sympathetic and Parasympathetic Nervous Systems.

c)       The spinal cord is surrounded by rings of bone called vertebra. These bones constitute the spinal column (back bones). In general, the higher in the spinal column the injury occurs, the more dysfunction a person will experience. The  vertebra are named according to their location. The eight vertebra in the neck are called the Cervical Vertebra. The top vertebra is called C-1, the next is C-2, etc. Cervical SCI's usually cause loss of function in the arms and legs, resulting in quadriplegia. The twelve vertebra in the chest  are called the Thoracic Vertebra. The first thoracic vertebra, T-1, is the vertebra where the top rib attaches.

d)       Injuries in the thoracic region usually affect the chest and the legs and result in paraplegia. The vertebra in the lower back between the thoracic vertebra, where the ribs attach, and the pelvis (hip bone), are the Lumbar Vertebra. The sacral vertebra run from the Pelvis to the end of the spinal column. Injuries to the five Lumbar vertebra (L-1 thru L-5) and  similarly to the five Sacral Vertebra (S-1 thru S-5) generally result in some loss of functioning in the hips and legs.

3.       What are the effects of SCI?  

a)        effects of SCI depend on the type of injury and the level of the injury. SCI can be divided into two types of injury - complete and incomplete. A complete injury means that there is no function below the level of the injury; no sensation and no voluntary movement. Both sides of the body are equally affected. An incomplete injury means that there is some functioning below the primary level of the injury. A person with an incomplete injury may be able to move one limb more than another, may be able to feel parts of the body that cannot be moved, or may have more functioning on one side of the body than the other. With the advances in acute treatment of SCI, incomplete injuries are becoming more common.

b)       The level of injury is very helpful in predicting what parts of the body might be affected by paralysis and loss of function. Remember that in incomplete injuries there will be some variation in these prognoses.

c)       Cervical (neck) injuries usually result in quadriplegia. Injuries above the C-4 level may require a ventilator for the person to breathe. C-5 injuries often result in shoulder (deltoid) and biceps control, but no control at the wrist or hand. C-6 injuries generally yield wrist control (wrist extensors), but no finger hand function. Individuals with C-7 and T-1 injuries can straighten their arms (tricepts) but still may have dexterity problems with the hand and fingers. Injuries at the thoracic level and below result in paraplegia, with the hands not affected. At T-1 to T-8 there is most often control of the hands, but poor trunk control as the result of lack of abdominal muscle control. Lower T-injuries (T-9 to T-12) allow good truck control and good abdominal muscle control. Sitting balance is very good. Lumbar and Sacral injuries yield decreasing control of the hip flexors and legs.

d)       Paralysis also has other effects as well as a loss of sensation or motor functioning Individuals with SCI also experience other neurological changes. For example, the person may experience dysfunction of the  bowel and bladder,. Sexual functioning is frequently affected in men with SCI, as they may have their fertility affected, while women's fertility is generally not affected. High spinal injuries injuries (C-1, C-2) can result in a loss of many involuntary bodily functions, including the ability to breathe. Breathing aids such as mechanical ventilators or diaphragmatic pacemakers may be needed to regulate a persons breathing in these cases. Other effects of SCI may include low postural blood pressure (Postural Hypotension), inability to regulate blood pressure effectively , reduced control of body temperature (poikilothermic), inability to sweat below the level of injury, and chronic pain.

4.       Spinal cord injury facts.

  a)        Nearly 200,000 people inthe U.S. live with a disability related to a spinal cord injury (SCI) (Berkowitz 1998)

  b)        Approximately 11,000 Americans sustain an SCI each year (CDC unpublished data).

  c)        The leading cause of SCI varies by age. Motor vehicle crashes are the leading cause among persons under age 65. Among persons age 65 and older, falls cause most SCIs (CDC unpublished data)

  d)        Sports and recreation activities cause an estimated 18% of SCI cases (Berkowitz 1998)

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Motor Neuron Disease

Motor Neuron Disease(MND) also widely know as Parkinson's disease (PD) is a degenerative disorder of the central motor neurons, therefore, affecting the nerve system.  It was first described in 1817 by James Parkinson, a British physician who published a paper on what he called "the shaking palsy." In this paper, he set forth the major symptoms of the disease that would later bear his name.

Researchers believe that at least 500,000 people in the United States currently have PD, although some estimates are much higher. Society pays an enormous price for PD. The total cost to the nation is estimated to exceed $6 billion annually.  The risk of PD increases with age, so analysts expect the financial and public health impact of this disease to increase as the population gets older.

Incidence and Prevalence

Parkinson's disease afflicts 1 to 1 1/2 million people in the United States. The disorder occurs in all races but is somewhat more prevalent among Caucasians. Men are affected slightly more often than women.

Symptoms of Parkinson's disease may appear at any age, but the average age of onset is 60. It is rare in people younger than 30 and risk increases with age. It is estimated that 5% to 10% of patients experience symptoms before the age of 40.

What causes Parkinson’s?

Our movements are controlled by nerve cells in the brain. To prompt a movement, the cells pass messages to one another - and to the rest of the body - using neurotransmitters. In healthy people, these messages are carried efficiently. But, in people with Parkinson’s, the messages are disrupted and are not transmitted smoothly to the muscles. This is when difficulties controlling movement arise.

The messages fail to transmit properly because of a lack of dopamine - one of the neurotransmitters involved in the control of movement. In people with Parkinson’s, between 70 and 80% of the cells which produce dopamine have degenerated and been lost. This occurs mainly in a small section of the brain called the substantia nigra. If there is insufficient dopamine, nerve cells do not function properly and are unable to pass on the brain messages, resulting in Parkinson’s symptoms.

While dopamine is the main neurotransmitter affected, other neurotransmitter abnormalities also occur in PD. This is one explanation why simply replacing dopamine does not necessarily result in the benefits expected. The abnormalities in other neurotransmitters may also explain why so many non-motor symptoms are present in Parkinson’s.

Why dopamine-producing cells become depleted is not clear. It is generally thought that multiple factors are responsible and areas of current research include ageing, genetic factors, environmental factors and viruses. It is also unclear why some people develop Parkinson's but not others.

 What causes failure of neurotransmitter’s activity?

The cause of Parkinson's disease is unknown. Many researchers believe that several factors combined are involved: free radicals, accelerated aging, environmental toxins, and genetic predisposition.

Dysfunctional antioxidative mechanisms are associated with older age as well, suggesting that the acceleration of age-related changes in dopamine production may be a factor.

Roughly one-fifth of Parkinson's disease patients have at least one relative with parkinsonian symptoms, suggesting that a genetic factor may be involved. Several genes that cause symptoms in younger patients have been identified. Most researchers believe, however, that most cases are not caused by genetic factors alone.

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Manual WheelChair Components

Push handles are extensions to the top of the backrest frame that project backwards from the wheelchair and permit an aid to help propel the chair from behind.

The back rest is the suspension between the upright components of the seat frame against which the operator rests his/her back.

Swing-away arm rests are the frame components on which the operator rests his/her arms. Swing-away arm rests may be rotated out of the way during transfers without having to remove them from the chair.

Wheelchair tires provide the contact between the wheelchair and the ground. They can be grouped into 3 general classes: pneumatic, semi-pneumatic, and solid rubber. Pneumatic are filled with air and provide a cushioned ride but are susceptible to flats. Semi pneumatic are filled with gel instead of air to maintain cushioning but eliminate the possibility of flats. Solid rubber are the most durable and maintenance free but provide the roughest ride.

The hand or push rim is attached to the outside of the wheel and

provides the surface against which the operator pushes with his/her hand to propel the chair. The hand rim is made of strong, lightweight material like aluminum.

The wheelchair frame is the rigid, tubular structure that supports the seat and the wheels.

The seat cushion is made of compliant material that permits the dispersion and absorption of force (pressure) between the operator’s

body and the sitting surface. Seat cushions come in many varieties across a wide range of prices.

The flip-up foot rest provides the support surface on which the operator’s foot rests. This type of foot rest may be flipped-up out of the way during transfers.

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A Guide to Wheelchair Selection

How to Use the ANSI/RESNA Wheelchair Standards to Buy a Wheelchair

Wheelchair Selection by Section: Download only the sections you want to read or print.

• Section One: Table of Contents, Acknowledgments, Message from PVA's director, and How to use this guide (256K .pdf file)
• Section Two: Standardized Testing and Information Disclosure (88K.pdf file)
• Section Three: General Considerations (112K.pdf file)
• Section Four: Incorporating Body Characteristics (68K.pdf file)
• Section Five: Manual Wheelchairs (140K.pdf file)

Text Only versions of sections one, two, three, four, and five of this booklet.

Guide to Wheelchair Selection: Download all sections of the booklet (Text only no graphics) (36K .txt file)

This book is provide by Paralyzed Veterans of America.

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