This is the second article by Dr Eleanor Roberts looking at brain fog, the range of cognitive difficulties experienced by people with ME/CFS.
Read part 1 here, which introduces cognitive function and the areas of the brain involved.
Cognitive dysfunction can be one of the most distressing symptoms for people with ME/CFS. This includes decreases in working memory, attention, ability to monitor errors, organisational skills, problem solving, verbal fluency and reasoning.
Introduction
There are a number of tests and techniques used to assess brain structure and function, and some of these were discussed
in a previous article.
There is clearly cognitive dysfunction in ME/CFS, and a 2010 meta-analysis revealed significant differences in information processing, working memory and attention in people with ME/CFS compared with healthy control subjects.
However, unlike a focused injury (such as occurs with a stroke), with ME/CFS no single brain region has been found to be disrupted in all people. Damage and changes leading to cognitive dysfunction may involve not only the
grey matter, where neuronal cell bodies sit, but also the
white matter, where axons send signals between different brain areas.
In addition to neuronal structural changes, problems may also arise due to changes in function. Furthermore, abnormalities may relate to problems in areas of the brain directly involved in cognition and/or other brain areas that influence these through the connections between them (
as discussed in part 1).
In this article, we look at a few of the many brain studies conducted in people with ME/CFS, concentrating on those that have examined areas of the brain directly involved in cognitive function: the
anterior cingulate cortex (ACC), the
dorsolateral prefrontal cortex (dlPFC) and the
lateral orbitofrontal cortex (lOFC).