Nervous system plasticity

Nervous system plasticity

Posted by AskNurseLinda on Sep 17, 2018 11:01 am

78173806096c4324b98bca0644480463-huge-isThe body wants to heal itself even if it has sustained an injury or has a disease. This is true, ongoing, if the event was just minutes ago or years ago. You can readily see the healing process if you get a cut or opening on the skin. At first, there will be some swelling to the area as fluid is pumped to the site to protect from infection as well as to cushion the opening. Redness will appear as the circulation increases to bring the fluid to the area. On the skin, you might see the cut close over with a scab and heal in a short amount of time. The area of the skin will form a scar as it mends itself.

The nervous system is much the same. In fact, all parts of the body are similar in healing, even if it is internal and cannot be seen. If the nervous system is traumatized, the same process is followed. Fluid is brought to the area to provide protection by swelling and to prevent infection with white blood cells to combat infection. The circulatory system is increased to bring these healing factors.

However, the nervous system is contained in ridged bones that cannot expand to accommodate the increase blood flow. These bones protect the central nervous system which consists of the brain and spinal cord. If additional fluid is present within the bones of the skull and vertebrae of the spine, the bones cannot stretch to accommodate the extra fluid. Therefore, the only way to make space in the hard bones is to compromise the delicate tissue of the nerves.

After an injury or disease to the spinal cord, a small hole is left in the center of the spinal cord. This becomes sealed off by scar like tissue. Just as healing of the skin, the process is much the same. However, this scar like tissue can also be a problem.  On the skin, the scar is not as elastic as the natural skin which can lead to pressure injury as it will not stretch. Internally, in the spinal cord, the scar like tissue will not allow nerve cells to pass through for connections.

All this seems to be a difficult picture however, the body always wants to heal itself and that is just what it will do using the concept of plasticity. Remember stories from your youth: don’t drink alcohol or you brain (and spinal cord) cells will die and they cannot be replaced. New brain (and spinal cord) tissue cannot be formed. WRONG! New information has clearly demonstrated that this was a myth.

One of the ways the body will try to heal its nervous system is through a process called plasticity which is the ability to remold or reshape something. In the central nervous system, neuroplasticity is the ability of the brain and spinal cord to create new ways of doing things such as sending and receiving messages to and from the body. Your brain is doing this throughout your life even without a spinal cord or brain injury. The brain is more flexible with younger age however it does not stop remolding itself at a certain age but continues to adapt throughout your lifetime.

Neuroplasticity is thought to occur in different ways. First, neurons are constantly changing. They grow stronger and weaker. New neurons are thought to develop throughout life. Just as your skin cells age and are replaced by new skin cells, so does all the tissue in your body, including nervous tissue. The issue is that nervous tissue is extremely slow at turn over. My guess is that since it is internal tissue, it does not have the high risk of injury such as external tissue like skin. Therefore, it probably does not need to be speedy in replacement under usual circumstances. However, in an injury or disease situation, we wish the turn over to be quicker.

Another way neuroplasticity is thought to work is through remapping of the way messages are transmitted. For example, there are predictable pathways that a message is sent from the brain to the toe and back again. After injury or disease, the messages are still being sent but they cannot flow through because of the spinal cord or brain injury. The body still wants to push the message through so the electrical discharge could possibly ‘leap’ to another near by nerve. Some nerve endings run particularly close to one another. This is a spot where the misdirection can occur.

The most familiar example of misdirection of nerve messages occurs in a heart attack. Most people are aware that when a heart attack occurs, often there is a pain that radiates down the left arm. Less well known is that the heart attack pain can also appear in the left shoulder or left side of the jaw. This misdirection of pain is at T4. At thoracic level number 4, there is a bundle of nerves that are located in a tight bunch. The message of a heart attack flows from the heart through this bundle.  The message of a heart attack is a huge chemical reaction which can spill over to other nerves in the bundle resulting in pain in the left upper body.

Another phenomenon of misdirected messages is the sensations of pain or itching of someone who has a body part amputated. The individual still might report ‘feeling’ their missing limb or other sensation where the body part is no longer located.

This thinking about neuroplasticity has been the theory for some time. However, it must be pointed out that one researcher has found neuroplasticity to not be true. This research did not find new nerve cells in the nervous system but there were some unidentified cells found. It could be what is called ‘new nerve cells’ are actually some other type of cell that have not yet been assigned for function by the body. So, the unidentified nerve cells can be called something else, but we still see the result of misdirected and redirected nerve messages after spinal cord and brain injury. Therefore, researchers use the knowledge we have to move forward and harness this nervous system energy.

An excellent example of harnessing nervous system energy was discovered in the research in which Christopher Reeve participated. He had joked about being able to move one finger on command several years after his spinal cord injury. It was slow and not strong, but he could move one finger on command. This was movement below his spinal cord injury that was clearly seen and extremely consistent.

To test and establish the consistency of the finger movement a fMRI was performed. fMRI is an MRI test using magnets to establish brain imaging. The f is an abbreviation for ‘functional’. An fMRI is a regular MRI examination, but the patient is asked to perform certain movements while the brain scan is being conducted. The results are displayed in color on a screen, so the examiner can see where the movement is originating in the brain. Unaffected movement is established measuring movement above the level of spinal cord injury such as tongue movement on command. Then the area of movement in the affected area is assessed. How the affected area movement appears might be different than usual locations in the brain for that function. This demonstrates neuroplasticity. In other words, the nervous system found a way around the injury site.

Some people have affected their brain function just by concentrating. The most definitive example of this is fMRI conducted in nuns who pray most of the day. The results indicate that their brain functions have been altered by this very devoted praying or ritualistic behavior.
Individuals, including Christopher Reeve, with spinal cord or brain injury have demonstrated remapping or redirecting functional tasks through activity stimulation or movement applied to the part of their body affected by SCI.

Specifically, what leads to this increase in function is unknown. It could be new nerves sprouting, remapping of the nervous system, activity to the body below the level of injury, or something altogether different that stimulates the new direction of messages being sent through the body. Each factor is still being researched. However, what we do know is that it does happen. Therefore, it is essential that individuals keep up their movement input to the part of their body affected by paralysis regardless of the cause.

Physical stimulation of the body along with mental stimulation, thinking about your body moving, is what is seemingly craved by the nervous system to develop new pathways for connections to the brain. Move your body or have someone move it for you. Look at your body moving and think about your toes wiggling or your knee bending while it is happening. These are the inputs that you can do to help restore function through neuroplasticity.

Nurse LindaI'm online in this community every Wednesday from 8-9 PM ET to answer your SCI and paralysis related questions.

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Re: Nervous system plasticity

Posted by bigwave916 on Oct 21, 2018 5:12 pm

Linda,

Very interesting and informative.  I volunteered many years ago to help a young man with an injury in what was called at the time "patterning"  We would get together once a week to stretch him and move his extremities as if he was walking.  Now, that I myself have a spine injury,, I have no one to keep my limbs moving other than what I can do myself.  PT is helping but I don't know how much longer insurance will cover.  I am thinking of getting a hand bike to try to stay active, but it seems to improve and to possibly walk again, I'd need some sort of "patterning"

Regards,
Dave

Re: Nervous system plasticity

Posted by AskNurseLinda on Oct 21, 2018 11:58 pm

Dear Dave, thank you for bringing up this important topic. As you have experienced patterned movement is extremely important to nervous system recovery. Your helping another has brought this to reality for you.
It is difficult to obtain the continued therapy but there are some ideas. First, the idea of a hand bike will help you maintain your upper extremities. There are bikes that will move your legs in tandem with your arm movement. That will cost a bit more. You can ask your healthcare professional for a letter of medical necessity for one.
Of course, the best equipment for patterned movement is electrical stimulation because you can get many rotations with your body doing the actual work. This therapy to learn to use the equipment and to purchase it is very expensive and often not covered by payors but you can ask for this as well. Asking never hurts.
Many people do their own patterned movement through range of motion which does not cost anything but is a start. The physical therapist can show you how to adapt the exercises to do on your own or to have a family member or caretaker assist you. Therabands can be purchased that will make your exercise a bit more challenging but also can assist with moving parts of your body that you might not be able to reach as well as adding resistance.
Some individuals have employed students to provide patterned movement for a small fee. Occasionally, people find others who are willing to help. Since you are tapped into the volunteer system for people to provide patterned movement, you could see if they would be able to start with you.
There is research that indicates this is a piece of the puzzle for neurological recovery. Unfortunately, payors have been slow to react to this success. The time for acknowledgement is growing quickly. Keep at it. You have the knowledge needed for success, now is the time to work it into your recovery in some way. Nurse Linda
 

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