Brain growth may compensate for damage in benign MS: MRI study

Certain brain regions found larger in people with benign RRMS

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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An illustration shows the human brain inside a person's head, seen in profile.

In people with benign relapsing-remitting multiple sclerosis (RRMS) who have minimal disease activity, there is a loss of overall brain tissue but specific parts of the brain may grow to help compensate for the damage, a new study indicates.

The study, “AI-driven MRI analysis reveals brain atrophy patterns in benign relapsing-remitting multiple sclerosis,” was published in Frontiers in Neurology.

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People with benign MS have few relapses, little disability

In most people with MS, the disease is marked by relapses (flares where symptoms worsen) followed by periods of recovery, and over time, their levels of disability tend to increase. However, for decades, it’s been known there are some people with benign MS who experience few or no relapses and have little disability years after their MS diagnosis. The presence of benign MS has been a puzzle for scientists.

Previous studies have shown that people with MS tend to experience brain atrophy — that is, a gradual loss of brain volume — at a faster rate than is seen in people who don’t have MS. In this study, scientists in Finland wanted to examine whether substantial brain atrophy is also present in people with benign RRMS who have little-to-no clinical disease activity.

“There are few previous studies reporting brain volumes in benign MS, with controversial findings,” the scientists noted.

For their study, the researchers conducted brain scans on 35 people with benign RRMS and 35 people who did not have MS and served as the control group. In both groups, demographics such as sex and age were comparable, with most participants (80%) being women. Around a third (32%) of those with benign RRMS had not received any disease-modifying therapy by the time their scans were taken.

Data showed overall brain volume was lower in the benign RRMS patients than in the healthy controls, which indicates that brain atrophy does occur faster than is typical in people who have this type of MS.

However, this atrophy wasn’t spread evenly throughout the brain. In fact, the researchers found certain regions in the brain were actually larger in the benign RRMS patients than in the healthy controls. This may be because these regions are growing to help compensate for the brain atrophy in other regions, which could help explain why these patients had such mild disease, according to the scientists.

Enlarged brain regions found in cortex, cerebrum, limbic system

Some of these enlarged brain regions were located in parts of the brain called the cortex and cerebrum, which are important for controlling complex thought and movement. Enlargement was also seen in parts of the limbic system, which helps the brain control emotional responses.

The researchers noted damage to the limbic system has previously been linked to cognitive problems in MS, lending credence to the idea that growth in this region could help compensate for brain damage elsewhere and limit the clinical symptoms of MS.

The researchers stressed, however, that more studies with larger numbers of patients will be needed to validate the findings of this study. They also noted that, although the data suggest some people with MS may experience compensatory brain growth, it’s not clear why or how this happens, so more research is needed.

“Our findings suggest that while total brain volume is significantly reduced in [benign RRMS] patients compared to [healthy controls], certain cortical regions, particularly within the limbic system, may exhibit relative preservation or even compensatory volume increases, but the plausible mechanism remains unsolved,” the scientists concluded.