• Roughly 40 percent to 65 percent of people living with multiple sclerosis (MS) have some form of cognitive challenges.
• Cognitive challenges can include trouble concentrating or following through on complex tasks, along with difficulty remembering events or finding the right words to use.
• Early comprehensive intervention may help maintain brain health, including slowing lesion growth.

Multiple sclerosis 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 MS will experience cognitive changes. These cognitive challenges may include issues with:

• Attention span
• Processing of information
• Memory
• Verbal fluency
• Decision-making

Recent studies suggest that cognitive dysfunction can occur earlier in the disease than previously thought. These challenges can impact a person’s ability to work, drive, socialize, and live independently. Studies have also shown a link between cognitive impairment in MS and anxiety and depression.

How Does MS Impact Brain Health and Cognitive Functioning?

As all adults age, they generally lose a small amount of brain tissue. In people living with MS, this loss may happen at a faster pace and connectivity (connections) of the brain can be disrupted.

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 symptoms of MS, including decreased mobility and cognitive functioning.

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

What Are the Signs of Cognitive Impairment?

Living with MS can be hard because it can affect so many areas of cognition and executive functions (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.”

Learn about cognition testing for MS.

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

Memory or Recall

Memory or recall problems can manifest in many ways, including difficulty 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!”

Attention and Concentration

Some people with MS may have difficulty focusing or inability to stick to one task without getting distracted. Attention problems are a common component of MS. In fact, one MyMSTeam member shared, “I am losing my train of thought.”

Information Processing

Being unable to respond quickly when a lot of information is being presented 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.

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 or trouble following through with multistep tasks are examples. One member of MyMSTeam wrote, “Minor things completely overwhelm me.”

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 also had to quit driving. I get left and right mixed up. I also forget where the places that I have driven to for years are!”

Verbal Fluency

Difficulty finding the right words or mixing words up are examples of declines in verbal fluency. “I can’t get my mind to spit them out,” wrote one MyMSTeam member.

When Do Signs of Cognitive Decline Appear?

Cognitive impairment symptoms may be observed 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 symptoms of MS are even noticed, so a diagnosis of MS isn’t necessary to experience cognitive symptoms.

The Importance of Early Intervention in Maintaining Brain Health

There are important lifestyle changes you can make to maintain your brain health as soon as you are diagnosed with MS. This 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.

Starting a comprehensive treatment intervention plan early on and sticking with it, along with lifestyle changes, may help slow the decline in brain health over time.

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

Starting treatment early may help reduce brain lesions. This 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.

Learn more about strategies for enhancing cognitive abilities with MS.

Although cognitive changes are a normal part of MS, you can do something about them. You can help improve your quality of life with the help of your doctor, therapist, neuropsychologist, and other health care team members.

Building a Community

MyMSTeam is the social network for people with multiple sclerosis and their loved ones. On MyMSTeam, more than 178,000 members come together to ask questions, give advice, and share their stories with others who understand life with multiple sclerosis.

Are you living with multiple sclerosis? Share your experience in the comments below, or start a conversation by posting on your Activities page.