Your Brain on MS
Multiple sclerosis may vary patient to patient, but the process that causes its symptoms? That's nearly the same in everyone.
After you’re diagnosed with multiple sclerosis (MS), your first questions might be, “What, exactly, is happening to my brain?” followed by, “How will these changes affect me physically, cognitively, and emotionally?”
Such brainy questions are important ones—they speak to how your very future may unfold. By walking through the ins and outs of this chronic condition, you just might be able to recognize and manage common MS symptoms, including problems with balance, motor skills, concentration, memory, and bladder and bowel habits—all connected to how your brain processes and relays information to and from different parts of your body. What's more, adopting doctor-recommended lifestyle changes gives you more control, better equipping you to combat MS as it progresses.
Here’s How the CNS Is Supposed to Work
Let’s start with what should be happening. The central nervous system, or CNS, is comprised of the brain, optic nerves, and spinal cord. The CNS connects with a network of nerves (called the peripheral nervous system, or PNS) that “speak” to the rest of the body. Together, the entire nervous system is made up of billions of neurons, each consisting of a cell and fibers, including long (and rather important!) ones called axons.
Information is constantly moving from axon to axon, from neuron to neuron. Think of it as your body’s communications network, one that depends on the production of electrical impulses in the neuron, which, in turn, triggers the release of chemical messengers (called neurotransmitters) that attach to the next neuron—which stimulates even more electrical impulses—and so on.
Some neurons receive information from your sensory organs, such as your eyes and ears, passing it along to your brain. Other neurons bring messages from your brain and spinal cord to your muscles, letting you do things like move, speak, and swallow. Within the brain itself, the neurons communicate with each other, allowing you to see, feel, hear, remember, learn, move, make decisions—everything you do that makes you human.
5 Ways MS Attacks Your Brain and Nerves
The health of every system in the body, including your CNS, depends on your immune system. A healthy immune system protects your body from invading pathogens—things like bacteria, viruses, or other microorganisms that cause disease—by launching an inflammatory response, which is supposed to battle pathogens.
But sometimes—for unknown reasons—the immune system gets it wrong. “Multiple sclerosis is an autoimmune disease in which the body's immune system mistakenly attacks normal tissues in the central nervous system,” says Mary Rensel, M.D., director of wellness at Cleveland Clinic’s Mellen Center for Multiple Sclerosis in Ohio.
This occurs after a breakdown of the blood-brain barrier, which we all have to protect our brains from invading pathogens. While researchers still aren’t certain why this breakdown occurs in people with MS, they do know that a leaky blood-brain barrier allows certain immune cells to cross over into the brain, which then cause inflammation. And inflammation not only makes the barrier even leakier, it also disrupts communication between the nerves by stripping the fatty, protective coating (called myelin) that surrounds them.
The myelin loss leads to scarring on your brain ("sclerosis" is another word for scar). And this damage is what brings on the many symptoms of MS. Without myelin, the conduction of messages between the brain and the body is short-circuited; processing speed slows down and information can even be lost.
As more lesions in the CNS develop, they further impair communication between different parts of your brain, as well as with the rest of your body. But lesions need not be visible for negative effects to take place. “Even normal-appearing brain tissue can be damaged in MS,” says Robert Bermel, M.D., medical director of the Mellen Center for MS at the Cleveland Clinic. Beyond the visible lesions, advanced imaging techniques in clinical trials have detected microscopic and molecular signs of inflammation, as well as changes in vital enzymes inside the nerve cells.
The haywire inflammatory immune response in MS also leads to degeneration of the structure and function of the nerve’s axon. This destruction occurs in the spaces between nerves (referred to as synapses) where the neurotransmitters operate, making it more difficult to transmit messages efficiently or fully. Talk about a multi-focal attack.
But there’s more. Everyone’s brain shrinks with age, but it shrinks faster in people with MS. In fact, it’s now known that cognitive problems often appear before there are any obvious physical symptoms of this disease. This shrinkage is called atrophy. It can be quite extensive in people with MS. “There’s global atrophy of the brain and spinal cord, probably from the get-go,” says Vijayshree Yadav, M.D., clinical director of the Oregon Health and Science University Multiple Sclerosis Center. “But we don’t know why it’s happening.”
The “why” question comes from a chicken-or-the-egg-debate among researchers regarding whether all that inflammation leads to degeneration and brain atrophy—or whether the inflammation and degeneration come first, which then cause brain atrophy. “Maybe there are cellular or molecular factors, or a lack of transport along the axon, and an energy failure that cause a global degeneration leading to brain atrophy,” Dr. Bermel suggests as one possible theory.
13 Ways MS Damage Affects Cognition
For many, cognitive dysfunction and the loss of cognitive reserve—the brain’s natural backup plan—may be the first sign that something is wrong. With the brain and CNS under siege from myelin loss, the destruction of axons, and atrophy, at least half of all people with MS experience cognitive problems as nerve signals are lost.
And, while the brain is able to adapt to some nerve cell and nerve fiber loss—and even to brain atrophy—by rerouting its signals to other undamaged areas that take over, this natural reserve is not unlimited. “As M.S. progresses, cognitive reserve decreases, which leads to difficulties with cognition,” says Dr. Bermel, who explains how this reserve is one of the areas where MS overlaps with normal aging. “If you layer MS on top of that process, you can think of the neurodegeneration of MS as accelerated aging,” he adds.
Many people with MS report how they struggle with:
finding the right word
multitasking (which requires attentiveness and concentration)
making plans and prioritizing them
retrieving recent memories (as opposed to memories from long ago)
“I started having trouble concentrating,” says Meredith O’Brien, 50, a writer whose memoir about being diagnosed with MS, *Uncomfortably Numb*, is being published in early 2020. “I had trouble reading newspapers and grading papers—I’d end up having to reread them,” she adds.
Much is still not known regarding MS and how it affects cognition—including why different people experience different cognitive issues, why someone can have cognitive issues even when brain structure appears “normal,” whether damage to one or more specific parts of the brain necessarily correlates with different cognitive dysfunctions, and whether one cognitive problem leads to another.
However, there is consensus that brain atrophy is considered to be the best predictor of cognitive decline and the progression of disability in people with MS. Atrophy is associated with:
personality and emotional changes
inappropriate laughing and crying
“Mood disorders, depression and anxiety, fatigue, and cognitive dysfunction are very common in MS, but are not often measured in the clinic,” says Dr. Bermel. He gives his patients questionnaires to track such symptoms. “These may be some of the symptoms that most impact a person’s ability to work and interact with their family—and they may be the most treatable,” he adds.
10 Additional and Common MS Symptoms
People with MS may experience a wide range of symptoms, all directly related to the signals from the brain being interrupted or lost either within the CNS, or from the brain to the peripheral body:
If damage occurs in the brain’s cerebellum, which is involved with coordinating movements, there may be problems with balance.
Damage to the optic nerve may cause optic neuritis, whose symptoms include eye pain, blurred vision, reduced color vision, or a blind spot developing in the visual field.
Damage to part of the medulla and pons area of the brain—responsible for the ability to both speak and swallow—can cause problems with speech and eating.
When found on the spinal cord, lesions can cause muscle weakness.
Some symptoms may be sensory—like feeling like you have” pins and needles” in your legs—and you may experience motor problems.
Other common symptoms include numbness and extreme fatigue.
Bladder weakness—a loss of control of how frequently, and where, you relieve yourself—are also frequently reported symptoms in people with MS.
It’s important to note that not everyone with MS has the same set of symptoms, nor do lesions on a specific place on the brain always (and the key word here is “always”) correlate with certain symptoms. “Much of the brain is diffuse in function,” explains Dr. Yadav. In other words, there is widespread brain activation for a specific function, so an injury to one part may not necessarily result in a particular set of symptoms. “Lesions are tiny” he adds. “Only a few millimeters.” An individual’s response to lesions can widely vary.
People with relapsing-remitting MS (RRMS) experience repeated attacks (flares or relapses) with a gradual remission between flares. Each relapse is an inflammatory attack, followed by the relapse that’s characterized by molecular repair of the damage, with the brain rerouting its signals to other undamaged areas that take over. But cognitive reserve isn’t unlimited, and, over time, recoveries are incomplete, leading to the next, more disabling stage of the disease, known as secondary-progressive MS (SPMS).
DMTs Can Help Reduce Symptoms
To reduce brain shrinkage and prevent disease flares, people with MS are treated with disease-modifying therapies (DMTs) such as Gilenya (fingolimod hydrochloride), Tysabri (natalizumab), and Ocrevus (ocrelizumab).
All DMTs work by suppressing aspects of the immune system to keep it from overreacting. DMTs reduce inflammation and the accumulation of lesions, which then help decrease the frequency and severity of attacks. Some, such as Tysabri, act on the blood-brain barrier, curtailing immune cells from passing through, while others, such as Gilenya, prevent immune cells from attacking nerves in the CNS, decreasing the frequency and severity of relapses.
Lifestyle Choices Can Help Prevent Disease Flares
Doctors encourage people with MS to live as healthfully as possible to maintain a healthy brain and body.
“A big component of MS treatment now is what we call a wellness component,” says Dr. Bermel. He says that as we age, it’s a good thing to be cognitively active. This means that it’s doubly important for people with MS to promote a healthy brain by doing things like taking classes, reading, and getting involved in hobbies that are cognitively enriching, such as learning a new language, playing strategic games, doing crossword puzzles, or taking up a musical instrument.
O’Brien keeps regular reminders on her phone, takes copious notes, uses photos to help her remember things, and has set up a Google family calendar with important events so she won’t forget them. “I don’t multitask,” the writer admits. She also makes consistent, quality sleep a top priority—experts say 6 to 9 hours per night is ideal. “I focus on the quality of my sleep because I know this affects my cognitive ability,” she says.
Managing stress is essential, too. “My neurologist encouraged me to get back into taking yoga and meditation,” O’Brien adds.
Dr. Bermel also recommends not smoking, being physically active to enhance cardiovascular fitness, and managing other chronic diseases, including high blood pressure, diabetes, and high cholesterol levels.
When it comes to MS, knowledge is power. So, knowing what’s going on in your brain and the rest of your nervous system can help you take control of your life. That includes working with a skilled physician to find medications that can reduce your symptoms and their progression. It also means resolving to adopt health-promoting habits to give yourself the very best chance for maintaining a functioning nervous system and minimizing disease flares going forward.
- MS and Nervous System Damage: American Journal of Managed Care. (2019). “The Pathologic Foundations of Multiple Sclerosis: Current Considerations.” ajmc.com/journals/supplement/2019/role-brain-preservation-management-ms/the-pathologic-foundations-of-multiple-sclerosis-current-considerations
- MS Symptoms and Brain Damage: Multiple Sclerosis and Related Disorders. (2016). “Brain health: time matters in multiple sclerosis. ” sciencedirect.com/science/article/pii/S221103481630102X
- MS Symptoms and Lifestyle: Neurological Rehabilitation: Optimizing Motor Performance. (2010). “Chapter 14: Multiple Sclerosis.” researchgate.net/profile/Phu_Hoang/publication/230554483_Multiple_Sclerosis/links/09e4150148edc00051000000/Multiple-Sclerosis.pdf?origin=publication_detail
- Nervous System Damage: Biomedicines. (2019). “Mechanisms of Neurodegeneration and Axonal Dysfunction in Progressive Multiple Sclerosis.” ncbi.nlm.nih.gov/pmc/articles/PMC6466454/
- Disease Modifying Therapies: Frontiers in Neurology. (2019). “The Effect of Disease Modifying Therapies on Disability Progression in Multiple Sclerosis: A Systematic Overview of Meta-Analyses,” frontiersin.org/articles/10.3389/fneur.2018.01150/full