Multiple sclerosis (MS) is a progressive disease of the central nervous system that is well known for its effects on a person’s ability to move. However, one of the lesser-known symptoms of MS is cognitive decline — sometimes known as cog fog or brain fog.

In fact, as MS progresses, approximately 40 percent to 65 percent of people diagnosed with the condition will experience cognitive changes. Recent studies suggest that cognitive dysfunction can occur earlier in the disease than previously thought. These challenges can affect a person’s ability to work, drive, socialize, and live daily life independently.

How Does MS Affect Brain Health and Cognitive Functioning?

As we age, we all lose a small amount of brain tissue. This is known as brain atrophy. For people living with MS, this loss may happen at a faster pace, and connections of the brain can be disrupted. This doesn’t mean MS can cause dementia akin to Alzheimer’s disease. Dementia is considered much more severe than the cognitive dysfunction seen in MS.

In addition, the brain’s ability to adapt to MS damage (such as brain lesions) can be slowly used up over time. This decline in brain health results in increased MS, including decreased mobility and cognitive deficits.

“I went to sign my name on a check, and I couldn’t remember how to spell my own name!”

— A MyMSTeam member

The loss of myelin (a fatty layer of insulation found on brain cells or neurons) also contributes to declines in cognitive functioning. Demyelination occurs during MS-related autoimmune attacks on the central nervous system.

What Are the Signs of MS Cognitive Symptoms?

It can be hard to recognize which changes are related to MS cognitive changes. Does MS affect memory? Can it make it harder to solve problems or think of words? While MS can cause symptoms such as dropping things, slurring speech, or feeling muscle weakness, these are not considered cognitive issues.

The National Multiple Sclerosis Association describes six categories of cognitive symptoms.

1. Problems With Memory or Recall

Memory impairment can show up in many ways, including difficulty with learning new material, forgetting appointments or someone’s name, or feeling disoriented and not knowing where you are. One MyMSTeam member commented, “I went to sign my name on a check, and I couldn’t remember how to spell my own name!” Another member wrote, “I had to quit driving because I forget where the places are that I have driven to for years!” Nearly 20,000 members of MyMSTeam have reported memory loss as a symptom of their MS.

2. Challenges With Attention and Concentration

Some people with MS may have difficulty focusing or an inability to stick to one task without getting distracted. Attention problems are a common component of MS. One MyMSTeam member shared, “I’m losing my train of thought.” Problems with focus may also be related to working memory, a type of short-term memory that is involved with completing immediate tasks.

“It’s like your brain is in slow motion.”

— A MyMSTeam member

3. Trouble Processing Information

Being unable to respond quickly to new information or having trouble handling deadlines can be signs that you’re having a hard time with information processing. “It’s like your brain is in slow motion,” a MyMSTeam member wrote. More than 2,800 members of MyMSTeam have reported experiencing slowed information processing speed.

4. Difficulty Problem-Solving and Dealing With Complex Tasks

Sometimes, a person with MS may have a difficult time problem-solving or managing complex tasks that may have been easier before MS. Missing the point in conversations, having difficulty with decision-making, or having trouble completing multistep tasks are examples. One member of MyMSTeam wrote, “Minor things completely overwhelm me.”

5. Changes in Visual-Spatial Abilities

Getting confused about directions or having trouble with depth perception are examples of visual-spatial problems. This is also common. As one MyMSTeam member commented, “Up, down, right, or left is something I have to think about, and it doesn’t come naturally.” Another member wrote, “I get left and right mixed up.”

6. Issues With Verbal Fluency

Difficulty finding the right words or mixing up words are examples of declines in verbal fluency. “I can’t get my mind to spit them out,” wrote one MyMSTeam member. Problems with word-finding have been reported by more than 5,600 members.

When Do MS Cognitive Symptoms Appear?

Cognitive impairment symptoms may appear one or more years before your MS diagnosis, or they may come much later. Sometimes, this decline in cognition may start to occur years before MS symptoms are even noticed, so a diagnosis of MS isn’t necessary to experience cognitive problems. The course of your disease, whether relapsing-remitting or progressive MS, may also influence the timing of new or worsening symptoms.

The Importance of Early Intervention for Brain Health

If you or your neurology team are concerned about cognitive changes, cognition testing can help you identify any problems. But there are important lifestyle changes you can make to maintain your brain health as soon as you are diagnosed with MS. These can include changes to your diet and exercise regimen, as well as adding puzzles, video games, or other brain games to your daily routine to help keep your mind active and increase processing speed.

“I’ve been in therapy for cognitive difficulties, and it has helped. It’s a daily struggle to keep focused, but it’s working.”

— A MyMSTeam member

Starting a comprehensive treatment intervention plan early and sticking with it, along with lifestyle changes, may help slow down MS and mental decline.

Cognitive rehabilitation therapy may also help. One member of MyMSTeam wrote, “I’ve been in therapy for cognitive difficulties, and it has helped. It’s a daily struggle to keep focused, but it’s working.”

Starting treatment for relapsing MS early may help reduce the frequency of MS relapses and the development of new brain lesions. This plan can also lead to a lower level of physical disability later in life (such as a decline in mobility). For example, some studies have shown that early intervention with a disease-modifying therapy may improve a person’s long-term MS prognosis.

Although neuropsychological changes are a normal part of MS, you can take steps to protect your cognitive abilities and improve your quality of life. The first step is talking to your neurologist about cognitive issues.

Adapting to Changes

Living with MS can be hard because it can affect so many areas of cognition and executive function (higher-order thinking). One member of MyMSTeam said, “I’m definitely functioning at a different level than I ever did. I’m forgetting things, constantly searching for words, and flat out do not have the attention span or even ability to read at the level I could 10 years ago. I’m still processing that loss. But knowing that it’s not coming back forces me to adapt and try to work through my new life.”

Building a Community

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 216,000 members come together to ask questions, give advice, and share their stories with others who understand life with multiple sclerosis.

Have you noticed cognitive changes? How have they affected you, and how have you been able to adapt? Share your experience in the comments below, or start a conversation by posting on your Activities page.