Symptom Management

Screening Key to Catching Cognitive Dysfunction

By Matthew Carraro M.D. and Aaron Boster M.D.

MS is well known to cause impairment of strength, sensation, walking, bladder, bowel, and visual functions. Until recently, cognitive dysfunction was under-recognized in MS. Many recent advances have led us to better understand the vital importance of cognitive dysfunction, and the growing need to identify, measure, and treat it.
Cognitive impairment leads to a significantly negative effect on quality of life, and is a leading cause of people with MS leaving the work force. Perhaps the largest challenge facing those with cognitive changes is simply recognizing that it exists. Cognitive symptoms can be subtle, are rarely sudden in onset, and can progress very slowly over time. This may lead patients, loved ones, and their care teams (doctors, advanced practice providers, nurses, etc.) to overlook what may seem to be relatively minor thinking difficulties. As a result, it is extremely important to actively screen for this, and educate those with MS and their families of these possible changes.
There have been numerous studies searching for an ideal screening tool for cognitive dysfunction in MS. Some of these options are briefly discussed here:
  • Symbol Digit Modalities Test: Taking only 90 seconds to complete, the SMDT is one of the most sensitive in-office screening tools readily available in both MS trials and practice.
  • The Perceived Deficits Questionnaire and Multiple Sclerosis Neuropsychological Questionnaire-self report: While these are two of the most commonly used forms, both correlate better with depression than cognitive dysfunction.
  • The MSNQ-informant report: Filled out by a close friend or family member, this has been shown to be a sensitive screen for cognitive impairment, but it is not always possible to have such a person attend a clinic visit. 
  • The Rao Brief Repeatable Battery of Neuropsychological tests: The BRBN is comprised of different components and detects cognitive problems in 71 percent of cases relative to more involved batteries. It includes the selective reminding test, the 10/36 spatial recall test, the symbol digit modalities test, the paced serial addition test, and the word list generation test.
While these screenings are helpful, the gold standard for cognitive assessment remains neuropsychiatric testing. This is a more involved process, including an intake visit to collect information about a patient’s background. The initial visit is followed by a second visit where testing is completed. Traditionally, this is a 6-8 hour day of testing. Certain centers have started tailoring their evaluations for the MS population, which has shortened these days to 3-4 hours. A third visit is scheduled to review the results of testing. Unfortunately, neuropsychologists are in short supply nationally and not all insurance plans cover neuropsychological testing. These barriers currently limit this important diagnostic tool.
Brain atrophy measures, especially gray matter volumes, correlate very well with cognitive impairments in MS. Until very recently, such unconventional imaging techniques were only available in the research setting. Today, newly validated, automated software packages are making such assessments of brain atrophy possible in the clinic. What exactly to do with brain atrophy results is another unanswered question. We anticipate that the field of brain atrophy will continue to grow and in the near future we can envision disease modifying therapy decisions based on brain atrophy changes.
It is difficult to predict who will suffer from cognitive changes, but these deficits tend to progress with time, accumulation of white matter lesions, and brain atrophy (shrinkage). Cognitive changes tend to be worse in primary progressive and secondary progressive MS than relapsing-remitting MS.
It is well established that early treatment with a disease-modifying therapy can help to slow the symptoms of MS. This is true of cognitive changes as well; even patients treated with first-generation DMTs showed improvement on multiple elements of the BRBN. To illustrate the importance of recognizing cognitive changes, keep in mind they may be the first sign of failing your DMT. While a physical neurological examination may remain unchanged, cognitive changes can prompt consideration of repeat MRI studies and possibly a switch from one DMT to another.
It is also important to recognize that other common changes from and comorbidities with MS can worsen or cause cognitive changes. These include fatigue, poor sleep, spasticity, chronic pain, depression, and medication side effects. It is critical for healthcare professionals to screen patients to determine if these issues could be worsening their thinking. Untangling the web of these complex symptoms is essential so that the root problem can be addressed.
In a situation where a person with MS is experiencing poor sleep, a careful history could reveal difficulty falling asleep due to poor sleep habits or “sleep hygiene.” This is readily treatable with behavioral modifications such as never watching television in bed, or forcing yourself to get out of bed if you have been lying awake for more than 15 minutes. The same patient history may also reveal symptoms of obstructive sleep apnea, including waking fatigued, snoring, and witnessed apneic episodes by bed partner. Such a history should lead to a formal sleep study (polysomnogram). Sleep might also be impaired from waking up to use the bathroom because of urinary urgency. In this case, a simple urinary antispasmodic medication may improve sleep, fatigue, and cognition with a single pill. Likewise, those with spasticity can suffer painful cramps and spasms that can significantly disrupt sleep.
Very commonly in people with MS, untreated or undertreated depression can lead to pseudo-dementia. The ability to pay attention decreases with depression, which can lead to cognitive changes. If you are unable to listen effectively, you will not form memories in a meaningful way. This can cause a feeling of forgetfulness. However, cognitive worsening can reverse as depression improves! In these cases, treatment with counseling or antidepressants should be considered.
Exercise can also have immense benefits in reducing pain and spasticity, improving sleep, and improving depression/anxiety. Neuro-physical therapy is a great way to engage people with structured programs that can be continued at home or a gym. We encourage our patients to be as active as they can be.
Some with MS may benefit from the judicious use of stimulant class medications, prescribed with careful supervision by their treating MS neurologist.
This review only scratches the surface of this emerging and important issue in MS care. We and many others in the fight against MS will continue to work to better understand this subject and give it the attention it deserves, both in articles like this, in research, and in the clinic. We challenge you as people with MS and their loved ones to advocate for yourself, talk to your care team, request cognitive screening with every visit, and discuss questions that may have been raised while reading this article.
Matthew (Max) Carraro, M.D. is a board-certified neurologist who is completing his fellowship in multiple sclerosis and neuroimmunology at OhioHealth’s MS Center. He is passionate about early implementation of highly effective disease-modifying therapies and the use of intrathecal baclofen pumps for the management of severe spasticity. Originally from Chicago, he completed his undergraduate training at the University of Wisconsin – Madison, followed by medical school, internship, and neurology residency at The Ohio State University Medical Center. In his free time Dr. Carraro enjoys running, hiking, cooking, and spending time with his wife, children, and dog.
Aaron Boster, M.D., is a clinical neuroimmunologist specializing in multiple sclerosis. As a neuroimmunologist, Dr. Boster provides diagnosis and treatment for all types of MS as well as a wide range of neuroimmunological conditions. These include neuromyelitis optica, neurosarcoidosis, central nervous system vasculitis, NMDA receptor encephalitis, transverse myelitis, optic neuritis, stiff-person syndrome and more. He also provides medical management of refractory severe spasticity with expertise in all treatment modalities including intrathecal baclofen. Dr. Boster is board-certified by the American Board of Psychiatry and Neurology and is a member of the American Academy of Neurology. He enjoys spending time with his wife and two children, weightlifting, playing chess, and likes trying new foods.