Study links loss of ‘white matter’ in brain to MS symptom

Executive control includes the ability to stop ourselves from
behaving impulsively. The researchers have found that executive
control deficits are connected to reduced white matter in the
frontal lobe of the brain.

by Anne Crawford

While treatments are becoming increasingly effective in countering many of the symptoms of multiple sclerosis (MS), linking actual changes in the brain to its more elusive symptoms is vital to driving the development of therapies that can ultimately halt the disease.

Monash University researchers, led by Associate Professor Joanne Fielding and Dr Meaghan Clough in the Department of Neuroscience, are investigating deficits in executive control, that is the way our ‘higher brain’ controls basic behaviour, and determining which area in the brain is driving these deficits.

“If we want to stop ourselves from doing something reflexive or impulsive for example, it’s our executive control that makes us stop,” Dr Clough said.

People with MS typically have poor executive control, poor planning ability and difficulties keeping ‘on task’, she said. Concentrating requires much more effort, is fatiguing and frustrating to them.

The Central Clinical School researchers found that executive control deficits are connected to reduced white matter – the connections between neurons – in the frontal lobe of the brain.

“This is the first paper that’s specifically linked a reduction in these connections in the frontal lobe, with the types of deficits that are significant in this particular disease,” Associate Professor Fielding said.

The researchers used video oculography to measure eye movements as a means of testing cognitive function.

Dr Clough (left) and A/Prof Fielding led the study

“By getting people to perform a range of simple eye movement tasks we can deduce which cognitive functions are affected,” Associate Professor Fielding said.

Dr Clough said the paper demonstrated that the method has some advantages over more conventional ways of detecting and gauging the extent of the disease.

“We’ve pretty much established that we can measure what is happening in the brain in a really simple and sensitive way without anything invasive like complex MRI,” she said. “We’re capturing the deficit at an earlier stage than more conventional methods.”

Many treatment options exist for MS. A sensitive method of measuring change would help give clinicians an indication of treatment efficacy – an early warning that treatment needed to be modified or that it was working, she said.

The findings may help in the future development of drugs or other therapies that could focus on re-establishing the connections in the brain damaged by the disease, the researchers said.

It could potentially help find a new and effective way in the future of detecting patients with early stage MS.

The study was published recently in the Journal of Clinical and Experimental Neuropsychology.

First author was doctoral student Dr Anne-Marie Ternes, supervised by Associate Professor Fielding and Dr Clough.

Ternes AM, Clough M, Foletta P, White O, Fielding J. Executive control deficits correlate with reduced frontal white matter volume in multiple sclerosis. J Clin Exp Neuropsychol. 2019 Sep;41(7):723-729. doi: 10.1080/13803395.2019.1614536. Epub 2019 May 20.