How MS Affects the Cerebellum

Medically Reviewed by Christopher Melinosky, MD on June 03, 2024
5 min read

Multiple sclerosis (MS) is an inflammatory disease that affects your central nervous system. That includes your brain and spinal cord. When you have MS, your immune system attacks your nerves and nerve cells.

Commonly, MS can affect a part of your brain called the cerebellum. Damage here can leave you with a wide range of symptoms, including shakiness, coordination problems, slurred speech, or trouble with certain higher-thinking skills.

MS affects everyone in a different way. There isn’t a cure, but treatment and lifestyle changes can help you manage your symptoms and may slow the advance of the disease. Talk to your doctor to learn more.

It’s easy to think of the brain as one big organ. But you can divide it into three parts. The cerebellum is a compact structure in the back of your head, right above your brainstem and below the large part of your brain, or cerebrum.

The cerebellum doesn’t have much volume, but it holds about 80% of the brain’s nerve cells. Those are cells that take information back and forth between different parts of your brain and nervous system.

This “little brain” plays a major role in balance, posture, and muscle coordination. It helps you:

  • Stand up straight
  • Walk without falling
  • Form words for speech
  • Move your muscles when you want to
  • Learn motor skills, like riding a bike or playing the piano

The cerebellum is well-known for its role in movement. But there’s growing interest in how it affects cognition, or how we think, feel, and act.

Experts suspect the cerebellum has a role in:

  • Language
  • Problem-solving
  • Social skills
  • Certain kinds of memory and learning
  • How we respond to rewards

More research is needed, but there’s evidence that the cerebellum may play a part in mental health and developmental conditions such as addiction, autism, and schizophrenia.

MS goes after two kinds of tissue in your cerebellum:

White matter. This tissue is deeper inside your brain. It’s filled with nerve fibers that connect nerve cells. These fibers are coated in a protective cover called myelin.

When you have MS, your immune system attacks myelin. “White matter lesions” can form in damaged areas. This scar tissue can disrupt signals from your nerve fibers. That makes it hard for your cerebellum to communicate smoothly with other areas of your brain or spinal cord.

The amount of white matter lesions you have can affect your symptoms and give clues about your health, including:

  • If you’re likely to progress to MS from clinically isolated syndrome
  • Your long-term outcome for motor and cognitive disabilities
  • If your drug treatment is working

Gray matter. This is the outer layer, or cortex, of your brain. It has a low amount of myelin but is packed with nerve cells, or neurons.

MS can leave “cortical lesions” in your gray matter. They can damage nerve connections and kill off neurons. Nerve cell loss is called atrophy.

Cortical lesions can show up in anyone with MS. But they’re more common in people who have primary progressive MS. If you have relapsing-remitting MS, lots of cortical lesions may point toward a secondary progressive MS diagnosis down the road.

Scientists used to think of MS as a white matter disease. But there’s evidence that gray matter damage can occur often and early on. Experts think cortical lesions – with or without white matter lesions – may be helpful when it comes to finding the therapies you need or how far along your disease is.

Cortical lesions are linked to:

  • Worsening disability
  • Thinking problems
  • Brain tissue inflammation
  • Shorter time until the disease gets worse

More research is needed, but some symptoms, such as a decline in mental skills, may depend more on how many nerve cells you lose in your gray matter rather than how many lesions you have.

It depends on how many lesions you have and where they are in your cerebellum. Nerve cell loss, brain inflammation, and disease activity also play a role in how you’ll feel.

But it’s common for cerebellar damage to make it hard to control voluntary muscle movements. That’s called ataxia, and it affects around 4 out of 5 people with MS. Your thinking and behavior may also change.

You may have one or more of the following:

Balance and walking (gait) problems. Three out of four people with MS have issues walking at some point in their life. You may take unsteady, wide steps, or walk slowly. You may fall more often.

Tremor. Different parts of your body may shake on their own. That includes your arms and legs, trunk, vocal cords, and head.

Speech trouble. Your words may come out slow and slurred, or you may break up syllables. Around 25% to 40% of people with MS get muscle-related speech problems, or dysarthria. It seems to be more common in people who have a progressive form of MS.

Less eye control. Your eyes may drift from side to side when you try to stare at something (gaze-evoked nystagmus). Or they may go up slowly on their own (downbeat nystagmus).

Cognitive problems. Your language, long-term memory, and higher verbal skills will likely stay intact. But people with MS who have lesions on their cerebellum tend to have poorer higher-thinking skills in other areas.

Damage to your cerebellum, for any reason, may cause you to:

  • Lose the ability to multitask
  • Have trouble paying attention
  • Forget the names of everyday things
  • Not be able to judge size or distance
  • Have trouble with big-picture thinking 

Cerebellum damage is common in relapsing-remitting MS and progressive forms of MS. In fact, it occurs in about 4 out of 5 people with the disease. But there’s no way to predict how MS will affect your brain.

Rarely, MS may affect only your spinal cord. About 2% to 5% of people diagnosed with MS might not have brain lesions, at least not visible on early brain scans.

Your doctor will ask about your medical history and current symptoms. They’ll give you a neurologic exam to check functions such as language, balance, and movement and coordination.

The next step is magnetic resonance imaging (MRI). These detailed scans are the best way to detect MS-related damage, especially white matter lesions. They can also help your doctor monitor old or new disease activity in your cerebellum.

If you’re diagnosed with MS, you usually need an MRI every 6-12 months.

Talk to your doctor if you’re worried about how MS might affect your cerebellum. In the future, some tests may be used to find damage before you have lesions or nerve cell loss.

If you already have MS, treatment and lifestyle changes can help you manage your symptoms. Ask your doctor about mobility aids, speech therapy, physical therapy, or other resources. Visit the National Multiple Sclerosis Society website for more information.