Don't know if people have commented on this presentation from the Programme. Thought I'd add, because I have some background in the area.
Neural correlates of fatigue: a voxel-based morphometric MRI study of CFS/ME, Whitney General, Bristol University.
Whitney General talk said:
Participants: 22 patients with CFS/ME (19 females) ill for 21 months; 22 sex- and age-matched healthy controls.
Results: Compared to healthy controls, CFS/ME patients have increased grey matter density in sensory brain regions and the frontal lobe; these are largely involved with executive function and attention. They also showed decreased brain grey matter density in the posterior medial parahippocampal gyrus; this part of the brain is involved with memory.
Tentative explanation: prolonged hyperactivity might be responsible for later atrophy, as reported by reduced grey matter in the occipital and frontal lobes of CFS/ME patients (Puri et al, 2012).
Future suggestion: we need to replicate with a much larger sample size.
These grey matter density results are likely to be artefactual, because sample size to low, and chances of false positives are high. This is a common problem in this kind of research.
But what I's most like to point out is the interpretation. Notice how the interpretation goes back to a psychogenic model of MECFS. Notice that General suggests our frontal and occipital ("sensory") lobes are
hyperactive. I think its important to understand what's being implied here. Not that we are smart and think a lot, but that we are
fretting over our symptoms.
Its unfortunate for the author that the hyperactivity is in the occipital lobes, and area almost entirely dedicated to visual processing (why would we be more active here, I wonder?) - but the author nearly managed to lose this fact by referring to these areas as "sensory" areas. Kind of makes it sound like it might be about bodily sensations, or something?
Edit: actually, reading the abstract again, the occipital lobes might not have been involved (just a reference to another study). "Sensory areas" is not clarified. even though the various different ones are spread very widely across the brain.
Note the Chalder fatigue scale results (self-reported fatigue) weren't mentioned. I'm figuring that because they didn't correlate with anything.
My thoughts?
* These grey matter studies require huge samples, and very careful matching of comparison groups.
* I don't think they can be used effectively in an exploratory way - you need a hypothesis as to which areas you think will be extra dense/sparse. Then test that. Not just fish away in the data till you find some difference.
* The results could be totally spurious. Or they could be real and related to some incidental difference between groups. Maybe the CFS/ME patients were more educated, for example?
* You cannot really infer from these results that any group is thinking more/less in a certain way. We simply dom't know enough about what these areas do to make this kind of "reverse" inference.
* Look how the results can be used to confirm a psychogenic view of the illness.