Researchers have identified a previously unrecognized subtype of multiple sclerosis (MS) — one that can lead to significant cognitive impairment while leaving the ability to move largely intact.
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Because healthcare practitioners don’t routinely test people with MS for cognitive issues and instead focus heavily on walking difficulties, patients with this cognitive-only MS subtype may be told their disease is “benign” or “stable,” says first author Annalaura Lerede, PhD, a postdoctoral researcher in digital healthcare at King’s College Institute of Psychiatry, Psychology, and Neuroscience in London.
As a result they may not get the treatment they need. “We don’t know whether current disease-modifying therapies [common MS medications] also improve cognitive function and are effective for people with cognitive symptoms,” says Dr. Lerede.
A New, At-Home MS Assessment for Cognitive Symptoms
Researchers in this study wanted to test the feasibility of using an online cognitive assessment platform, called Cognitron, to measure and monitor cognitive impairment in people with MS.
They recruited more than 3,000 people with MS to complete a disability assessment from home. Using those results, researchers curated a series of tasks sensitive to cognitive functions impacted by MS.
Examples of the tasks include:
- Memory Tasks Participants are shown a list of words or pictures, then later must identify which ones they’d seen before.
- Attention and Speed Tasks The test displays colored words (for example, the word “BLUE” written in red ink) and requires keyboard responses based on changing rules.
- Problem-Solving Tasks After seeing block patterns or shapes, participants choose the missing piece to complete the puzzle.
- Word and Language Tasks Participants are offered word pairs to identify a connection, or multiple-choice definitions to test vocabulary.
The researchers then had a new group of participants complete the refined assessment, and then validated the findings by comparing the results to standard in-person tests.
New MS Subtype Revealed Through Testing
When researchers analyzed the results, they identified four main symptom patterns. One cluster, representing about 26 percent of participants, stood out: people with MS who had substantial cognitive problems but little or no motor disability.
This “cognitive-only” group included individuals across all ages and disease stages, suggesting that thinking problems can appear early in the course of MS and persist over time. Because these MS patients don’t show obvious movement issues, doctors may not recognize their challenges, the authors wrote.
“MS symptoms are different for everyone and often invisible,” said Catherine Godbold, PhD, of the MS Society, which supported the research. “But for too long, cognition has been overlooked and neglected, leaving people to struggle alone without access to the right treatment and services.”
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Why Is It So Hard to Diagnose ‘Cognitive-Only MS’?
This study was well-conducted and the findings are “highly significant,” says Christopher Lock, MD, a clinical associate professor and neurologist who specializes in MS at Stanford University Medical Center in California.
“Cognitive impairment is often difficult to assess in everyday clinical practice. There is generally a wait to see a neuropsychologist, and the testing involves a three to four hour assessment,” says Dr. Lock, who wasn’t involved in the study.
The most common MS assessments, like the Expanded Disability Status Scale (EDSS), are largely based on gait, he points out — in other words, focused on mobility, while underemphasizing cognitive issues.
“This research provides a viable and easily implemented means of testing cognitive function at home, and could help vast numbers of people better understand their condition,” says Lerede. The screening is cost-effective, efficient, accessible, and scalable, she adds.
Lock agrees that the cognitive impairment picked up by the new assessment would not have been identified by the usual assessments. However, the findings reinforce what he sees in his practice. “Patients report cognitive symptoms which may seem out of proportion to the findings on neurologic exam and MRI,” he says.
MS symptoms span a highly variable spectrum, says Lock. “We see patients with significant motor impairment without cognitive symptoms, and conversely other patients with few exam findings but with the less visible symptoms of MS, such as prominent fatigue and cognitive impairment,” he says.
New Tool Could ‘Empower’ People with MS
For people with MS who feel like their thinking issues are dismissed or overlooked because they don’t have corresponding physical symptoms, this new evaluation tool could “empower them to test themselves and go back to their clinicians with an objective proof of their perceived problems,” says Lerede.
Being able to more easily assess cognitive issues may also improve outcomes, even for people already taking medications, says Lerede. It’s possible that their treatment isn’t adequate because their perceived disability may be underestimated, she says.
First Step Toward Better Care and Assessment of All Types of MS
For now, Lerede hopes that the online test will help doctors and patients better measure and monitor cognitive function over time. The test could also help improve cognition measurement as an outcome in MS clinical trials.
“From the diagnosis perspective, we have highlighted the presence of cognitive deficits early on. Since our assessment battery can be administered at a very large scale, we are now evaluating its potential to detect early signs of MS in a scalable and efficient way,” she says.
Researchers hope to continue to offer the test and validate it in other populations throughout Europe.
“We want to provide both patient-facing and clinician-facing reports at the end of the assessment to inform patients on their results, as well as provide an output that they can show to their clinical team to inform clinical decision-marking around their management and treatment plan,” Lerede says.
Investigators also want to relate cognitive problems to corresponding brain pathology via imaging studies, she says.
