Photo Credit: Naeblys
Findings from a retrospective study show that, in MS, cognition can decline independent of relapse as well as independent of worsening physical disability.
“Substantial physical disability worsening in relapsing-remitting multiple sclerosis [RRMS] occurs outside of clinically recorded relapse,” Tom A. Fuchs, MD, PhD, and colleagues wrote in Multiple Sclerosis Journal. “This phenomenon, termed progression independent of relapse activity [PIRA], is yet to be established for cognitive decline.”
Dr. Fuchs and colleagues conducted a retrospective study of 336 patients with RRMS (80.7% women; mean age, 43.1) to investigate the concept of PIRA for cognitive decline and its implications. Cognitive decline was classified as PIRA if the following conditions were met: no relapse between assessments nor within 9 months of cognitive decline.
Physician’s Weekly (PW) spoke with Dr. Fuchs to learn more about the study and its implications.
PW: What prompted this work?
Dr. Fuchs: Recent research has taught us that a majority of physical disability in MS accumulates independently of relapse. This challenges previously held beliefs about the way patients with MS accumulate disability and pushes us to ensure our treatments not only control relapses but also the physical decline we see in our patients. This problem is similarly relevant to cognitive decline, which is important to our patients’ quality of life, work, and relationships. Nonetheless, until now, there has been no research on cognitive progression independent of relapse.
What are the most important findings?
Not only can cognition decline independent of worsening physical disability, but also independent of relapses. Because patients and their physicians tend not to catch cognitive worsening during interviews and physical examinations, cognitive decline can worsen silently without us noticing. This means we are missing this important component of disease progression, which constitutes an axis of disease progression that is otherwise not captured without objective cognitive testing.
How can these findings be incorporated into practice?
Silent cognitive decline can be well-captured with objective cognitive testing. First and foremost, we can capture our patients’ cognitive decline if we obtain a clinical baseline. If we perform cognitive testing on our patients early, we have a point of comparison when we choose to test our patients again. As in our study, I recommend using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS), which takes 18 minutes to administer. Then, to detect change, clinicians can apply reliable cut-offs such as those published in our paper: 8 points on the Symbol Digit Modalities Test, 7 points on the Brief Visuospatial Memory Test, and 11 points on the California Verbal Learning Test.
What makes this issue particularly urgent?
Our results highlight that cognitive decline can occur silently without us noticing. Thus, because cognitive testing is not a part of the clinical routine in many centers, many patients may experience worsening diseases that remain unaddressed. If clinicians more commonly incorporate baseline cognitive testing into their routine practice, they can identify cognitive decline when it occurs. This information can be used in two pivotal ways: (1) we can provide our patients with treatment recommendations, such as early preventative strategies for building or maintaining a reserve to buffer against future decline, and (2) cognitive decline can be explained to patients and their families so that these issues can be appropriately accommodated at work and home.
What should future research focus on?
It will be important for future research to validate our findings in other research centers. It is also important that we validate our findings with prospective research because many methodological issues are associated with retrospective analyses. Lastly, it is important for us to investigate cognitive PIRA in relation to disease-modifying therapies and brain MRI to evaluate treatment effects and determine whether silent cognitive decline events occur in relation to acute brain inflammation.
Is there anything else you’d like to mention?
It is important to remember that cognitive decline is treatable if caught early and can be treated with holistic lifestyle interventions or with well-studied, self-administered, home-based cognitive telerehabilitation. Furthermore, if cognitive decline is sufficiently severe that restorative rehabilitation is no longer an option, patients can be provided with compensatory cognitive strategies or accommodations at home and work. Lastly, we as clinicians can speak with our patients about their cognitive decline so that they can discuss these real, though invisible, neurologic issues with family and colleagues. This helps prevent unnecessary conflicts in relationships and at work thanks to a mutual understanding of the real, though invisible, neurologic issues associated with MS.
