Researcher finds ‘gold standard’ test for freedom from MS

For seven years, researcher Dr Meaghan Clough frequently observed multiple sclerosis (MS) patients performing on the standard test used to measure cognitive function, then told her about the cognitive problems they faced. She wondered about the gap.

“Upon further investigation, I would realize that they actually had a cognitive deficit,” Dr Clough said.

Deficits in working memory (WM) and attention are common – and concerning – symptoms of MS.

Dr. Clough decided to investigate the “gold standard” test for cognitive speed therapy used to diagnose and measure changes in MS patients. The Symbol Digits Modality Test (SDMT) asks the person to match symbols with numbers from one to nine.

“Recent reviews of the test have come out arguing that this is the one measure used if you wanted to determine if your patient has some kind of cognitive deficit – you give him this and this test and he says ‘yes’ or ‘no,'” Dr. Clough said.

A study by researchers at the Ocular Motor Research Laboratory, Department of Neuroscience, led by Dr Clough, found that this was not true for working memory deficits in patients with stage MS. early.

The results were published in The Journal of Clinical Medicine.

Dr. Clough gave a cohort of 88 people (63 with early MS and 25 healthy controls) a battery of different tests over five years. These tests targeted four types of WM functions: auditory; visual-spatial; executive (information integration); and episodic function (retaining information for use in long-term memory).

“I think one of the biggest problems is that people don’t really define what the patient has and they take a kind of lump-sum approach – one size fits all,” she said. “You might have a patient who has auditory working memory issues, but you assess them using a visuospatial working memory test.”

The research was the first and only study to investigate WM phenotypes in early MS, Dr Clough said.

He found that among the early MS cohort, more than 60% had WM impairment. “Deficits in working memory and attention have the most devastating impact on a patient’s daily life,” Dr. Clough said. “They impact a wide range of daily tasks such as following instructions or conversations, reading comprehension or organization and can lead to the patient quitting work or withdrawing socially,” he said. she declared.

Research found that visuospatial working memory was most affected in early MS, with patients often also having multiple impairments in other WM functions.

“The next level was – is there a test that we can use that gives us very good sensitivity in detecting patients with working memory impairment, whatever type it is, so that we can give patients a test and that we are more likely to detect people with a deficit, whatever it is?”

Again, the visuospatial WM test proved most useful.

A final experiment aimed to determine the best test to measure the evolution of the patient’s working memory over time. “What I found was that the working memory tests I reviewed had a ‘training effect’ – patients improved with training.

“We can’t see if medication or cognitive rehabilitation improves anything because we’re just measuring the effect of the practice.

“The WM visuospatial test was actually able to show that the patients got worse over time, as expected.”

Dr Clough said a simple, specific test based on visuospatial function could be done by neurologists to screen for cognitive deficits, and then further investigation using tests for other functions could determine the specific deficit of each patient. This would be beneficial clinically and in clinical trials, she said.

“I think the study is a really important step forward because the focus is really on how we treat or improve the lives of these patients. Right now we’re trying things that don’t work.

Dr. Clough is currently fine-tuning a new test.

Associate Professor Joanne Fielding is the final author of the article.

Clough, M; Barthelemy, J; White, OB; Fielding, J. Working memory phenotypes in early-onset multiple sclerosis: assessment of phenotype frequency, progression and sensitivity. J. Clin. Med. 2022, 11, 2936.