Brain function determines our personality, emotions, and intellect (cognition)—the attributes that make us unique. MS has the potential to affect these brain functions, either directly or indirectly.
Cognition is sensitive to many potentially disruptive factors. These include normal aging as well as disease or injury. It can also be affected temporarily by tension, emotional stress, depression, sleep disturbance, menopause, or fatigue. Cognition may be influenced by nutrition: for example, low blood sugar (hypoglycemia). And it can be disrupted by some prescription drugs or by drug or alcohol abuse.
The idea that MS might have cognitive effects is upsetting, but the facts emerging from research are encouraging. For example, although cognitive issues are common, they are often not severe.
Which cognitive functions can be affected by MS?
Although investigators are still in the process of answering this question, some consistent information has emerged.
Memory or recall problems are the most frequently reported. Memory loss seems to be confined largely to recent events. For example, you may have trouble remembering an important phone number learned in the past year. In contrast, you will likely have little difficulty remembering information from the distant past.
Studies show that two types of memory processes may be faulty. The first process is the ability to recall information that has been learned and stored. This may be the most common reason for memory problems. The second is that some people may have trouble learning to begin with—not being able to learn certain facts will make it difficult to recall them later.
Using cues may help to identify the source of a memory problem. A person who has learned new information but who cannot recall it may be helped when he or she is given a cue. On the other hand, using cues will not help a person who has not been able to learn the information to begin with.
Abstract reasoning and problem-solving abilities are sometimes affected. Problem solving is multi-faceted and includes analyzing a particular problem, identifying the central components that need altering, planning a sequence of events to bring about the change, and finally putting the pieces together to effect the change. Moreover, flexibility is often required to achieve these goals. People who cannot manipulate information to problem solve in this way are said to have a “dysexecutive syndrome”.
Visual-spatial abilities can be affected by MS. These include the ability to recognize objects accurately and to draw or assemble things. Visual-spatial abilities are involved in many everyday tasks such as driving, finding your way around, or packing a suitcase.
Verbal fluency is another area of cognition that can be affected by MS. Fluency problems are different from MS speech problems, which slow speech down or change voice quality. A fluency problem often shows itself as the “tip-of-the-tongue” phenomenon: you want to say a word, it’s on the tip of your tongue, but your just can’t think of it.
Speed of information processing. Both recall and verbal fluency skills require rapid processing of information. Slowness in mental speed, also termed “delayed information processing speed,” is the main cognitive problem linked to MS. Cognitive tests that demand quick responses are therefore helpful in unmasking cognitive problems in someone with MS.
How do cognitive problems arise?
MS may directly cause cognitive difficulties in a number of ways.
Lesions (or areas of scarring) have been linked to cognitive problems. Studies have found that areas of scarring occur with roughly equal frequency in the right and left halves of the brain, in areas called the cerebral white matter, where myelin occurs in abundance. MS lesions are particularly common near the ventricles—or inner cavities of the brain—through which the cerebrospinal fluid flows. Studies using magnetic resonance imaging (MRI) have shown a clear relationship between the presence of these lesions and cognitive problems.
Finally, new MRI techniques can now provide information about changes occurring in the brain structure that we haven’t been able to observe before. Some of these subtle changes have also been linked to cognitive dysfunction.
How common are cognitive problems?
Research has shown that about half of all people with multiple sclerosis living in the community show no evidence at all of intellectual problems. About 40% have mild dysfunction, while about 5-10% have moderate to severe impairments.
But what do mild or moderate problems mean in people’s lives? This question is hard to answer because people’s circumstances vary so much. For one person, mild intellectual impairment or cognitive problems could require a major life shift—the end of a career or course of study. But another person with the same degree of impairment might need no change in lifestyle at all, because he or she is able to cope, for instance, through accommodations in the workplace.
Detecting cognitive problems
A professional evaluation may be called for if you or those closest to you notice a change for the worse in cognitive function. For example, do you have increased trouble remembering things? Is it becoming harder to stay focused on a task? Do you experience lapses of judgment, trouble coming up with words in conversation, slowed thinking, or difficulty organizing projects or daily activities?
An evaluation is particularly important if any of these changes get in the way of your work, school, or social life, or create a stress for you. An evaluation may also make sense if you are planning to enter school or a training program.
Treatment for cognitive problems
Medication. Research concerning the use of medications is ongoing and a couple of studies have yielded modestly promising results. Your doctor will be able to tell you if any of these are appropriate for you.
Cognitive Rehabilitation. In the past few years the use of cognitive rehabilitation for MS has increased, as techniques have been developed to tackle the more common problems. Cognitive rehab is designed to help people compensate for loss of memory or slowed learning ability. It is provided by neuropsychologists, occupational therapists, or speech/language pathologists. Ordinarily, cognitive rehab involves one or more sessions a week over several weeks or months; each session typically lasts about an hour. These sessions might include doing exercises designed to enhance memory, concentration, or spatial skills. A good deal of time may be devoted to “compensatory strategies” such as learning how to be more organized, how to use a computer effectively, how to manage time, or process paperwork.
The goals of treatment are individualized and progress towards; in many instances, the cognitive rehab program may include meetings with family members to help them understand the nature of specific problems and how they can help. Stress management, counselling, or psychotherapy can be added to the treatment plan if needed.
What can be done to help alleviate cognitive problems?
Get it out in the open. Talk over your concerns with your doctor or nurse. Share with the people who are close to you. Very often, fears about a problem are much worse than the reality. Family members may not realize that a person with MS is experiencing some cognitive problems due to their illness. When someone with MS forgets parts of conversations, misses appointments, or misplaces things, it may be misinterpreted as laziness, indifference or carelessness .If this happens, family and friends need help to develop an understanding of what is going on.
Get counselling if it seems appropriate. Not everyone who experiences a few memory lapses needs counselling, but it can help people deal with the impact cognitive problems have both on self-esteem and on practical everyday living. It can also address depression or anxiety, which can adversely affect intellectual function.
Explore self-help options. Where memory is weak try substituting organization—get a good smartphone or even a paper organizer to help you keep track of everything. When you are trying to learn something new, give yourself extra time to practice: studies have shown that with extra practice people with MS can improve their ability to recall information later. Assign a particular place for storing frequently used items, like your car keys. Plan your most challenging intellectual tasks for your best time of day. When you encounter word-finding problems, don’t persist in trying to think of that elusive word. Try to shift your attention to something else—the word you want will come back to you later.