MS and Cognition

By Charles Yanofsky, MD

I’ve been noticing a heightened emphasis on cognitive function in persons with MS. Patients getting information from the Internet or attending meetings expect that they are going to have problems with mental function. They are shown scary MRI images of progressive brain atrophy and there’s a rush to find newer MRI techniques to show abnormalities in “normal appearing brain” to show one competing treatment is more effective than others.

As a rule, cognitive issues may surface late in the disease when more brain volume is affected, rarely early on. Yet a lot of folks are convinced they are having problems with mental function right after they are diagnosed. They notice small changes and fear they’re significant. While they may think their mental faculties are going, anxiety, depression, a sleep disturbance or fatigue are far more likely culprits. There is no substitute for determining what is actually wrong before planning treatment.

MS related cognitive problems most of the time aren’t very obvious to your neurologist. We do see some few people late in their disease who have a lot of affected brain and are inappropriately jocular or emotionally labile. Neurological articles emphasize that practicing neurologists underestimate cognitive dysfunction in MS, that if we look hard enough a problem will be found in up to 65% of persons with MS. That implies we are undertreating a serious problem. I’m not sure this is true. We neurologists aren’t too bad at assessing mental function. Hopefully we know our patients listen and note alterations thought processes and mental power.

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What we need and don’t have is a quick office based test to measure cognitive function. That’s because MS does peculiar things different from Alzheimer’s and true dementing diseases. MS rarely affects language function and recent memory that are easy to appreciate on quick mental state tests. Instead we depend on tedious neuropsych tests. After we invest all the time and expense in these, many questions go unanswered and test are liable to erroneous interpretation but they do provide documentation for employers.

MS is a disorder of communication. Patches of cerebral cortex are responsible for specific mental tasks, one for touching, one for smelling, for seeing an object. A separate area attaches a name, much like a computer plug-in module. What causes cognitive problems is a slowing or failure of communication between these modules. You will experience cognitive dysfunction when a lot of these communication cables fail. The classic problem with memory is that the idea gets in and is registered but you can’t think of it or retrieve it. That’s because the language module is ok and so is storage but the cable between them is frayed. Given enough time you will dredge the memory up. You may notice slowed processing , trouble planning and putting a mental strategy together but with patience, you may eventually succeed. Processing speed and multitasking may suffer in MS. The executive function of the frontal lobe that depends on inputs from all over the brain suffers more than anything else. Just like with other problems navigating around a deficit requires extra effort and diligence leading to frustration.

There are practical guidelines for cognitive troubles. Enlist the help of your neurologist to be sure you are in fact having cognitive problems, not anxiety, depression or fatigue which require different treatment. Simply staying calm, budgeting energy, giving yourself more time, not getting impatient with yourself and having an inner confidence that things will get done in their own time can be invaluable. Mental aids such as keyboards and Palms or simple writing pads can help as well as finding the right significant others, supportive positive persons around you. Certain drugs such as donepezil, modafinil can help too and finally you can look again at your treatment scheme with immunomodulators and MRI scans.