Task related cerebral blood flow changes of patients with chronic fatigue syndrome, 2018, Staud et al

[adambeyoncelowe]

Task related cerebral blood flow changes of patients with chronic fatigue syndrome: an arterial spin labeling study
Roland Staud,Jeff Boissoneault,Jason G. Craggs,Song Lai &Michael E. Robinson
Received 05 Dec 2017, Accepted 13 Mar 2018, Published online: 20 Mar 2018

ABSTRACT
Purpose: One hallmark of chronic fatigue syndrome (ME/CFS) is task related worsening of fatigue. Global brain hypoperfusion, abnormal regional activation, and altered functional connectivity of brain areas associated with cognition and memory have been reported but remain controversial.

Methods: We enrolled 17 female participants fulfilling the CDC Criteria for ME/CFS and 16 matched healthy controls (HC). Using a 3T-Phillips Achieva MRI-scanner, pseudo-continuous arterial spin-labeling (pCASL), was used to study the dynamics of regional cerebral blood flow (rCBF) and their relationship to mental fatigue in ME/CFS patients and HC during a demanding cognitive task, i.e. modified Paced-Auditory-Serial-Addition-Testing (PASAT).

Results: ME/CFS subjects reported more fatigue than HC at baseline (p < .01). Global brain perfusion of ME/CFS and HC subjects was similar at rest. The PASAT resulted in significantly increased fatigue in ME/CFS participants and HC. Although not different between groups, overall CBF significantly increased over the first 3 min of the PASAT and then decreased thereafter. Regional CBF (rCBF) changes were significantly different between groups during the post-task recovery period. Whereas improvement of fatigue of ME/CFS subjects was associated with decreased rCBF in both superior temporal gyri (STG), precuneus, and fusiform gyrus, it was associated with increased rCBF in the same areas in HC.

Conclusions: Our results suggest that ME/CFS is associated with normal global CBF at rest and during a strenuous task (PASAT); however rCBF of several brain regions associated with memory, goal-oriented attention, and visual function was differentially associated with recovery from fatigue in ME/CFS patients and HC.

KEYWORDS: Arterial spin labeling, regional cerebral blood flow, chronic fatigue

Link: https://www.tandfonline.com/doi/abs/10.1080/21641846.2018.1453919?journalCode=rftg20&

 

[adambeyoncelowe]

Another study finding reduced cerebral blood flow in certain areas after exertion.

What I find from personal experience is that there's an acute response to exertion where I get very dizzy and sheet white, but this resolves and then there's a different response a day or three later, which is more flu-like. So I'm wondering if these brain changes only occur during a very small window, which might account for contradictory studies?

Obviously, this is all anecdote, but I'm interested in hearing if other people think this is important too?

 

[Chris]

and then there's a different response

That is how I see it as well, the reduced blood flow is not the whole story when you crash but only the initial state of things, and then the brain during this hypoperfusion "crisis" sends signals which trigger all kinds of responses.

Something I have read is that one of those immediate responses would be an adrenaline surge to increase blood flow to the brain, without much success it seems and afterwards our weak bodies can not withstand this adrenaline. So you start crashing, systems shut down, etc. (would that adrenaline surge also trigger an immune reaction when there is one or is the immune response independent, I have no idea)

 

[adambeyoncelowe]

I can certainly hear my heart making a squelching sound in my ears afterwards, while I'm dizzy. Whether it's adrenaline or just the heart struggling to get blood where it's needed (or both), it definitely feels like a lack of blood in the brain.

 

[Ravn]

What I find from personal experience is that there's an acute response to exertion where I get very dizzy and sheet white, but this resolves and then there's a different response a day or three later, which is more flu-like. So I'm wondering if these brain changes only occur during a very small window, which might account for contradictory studies?

I have a similar 2-stage response, with stage 2 being much, much worse.
I suspect you're right: research results will differ dependent on when measurements are taken in that sequence of responses.

 

[MSEsperanza]

Whereas improvement of fatigue of ME/CFS subjects was associated with decreased rCBF in both superior temporal gyri (STG), precuneus, and fusiform gyrus, it was associated with increased rCBF in the same areas in HC.

I wonder what this could mean?

Have these findings been replicated?

(Don't have access to the paper.)

 

[SNT Gatchaman]

(Don't have access to the paper.)

Older paper, but here are summary quotes.

ASL Arterial spin labelling (MRI neurovascular perfusion technique)
CBF Cerebral blood flow
STG Superior temporal gyrus (auditory)

We used ASL to study the dynamics of regional CBF (rCBF) changes related to mental fatigue in ME/CFS patients. We hypothesized that rCBF changes during a fatiguing cognitive task would differ between ME/CFS and HC participants in areas related to attention and memory. Because previous work from our group suggested that ME/CFS was associated with alterations in functional connectivity (FC) in a number of brain areas , we postulated that the same brain regions would be associated with fatigue related blood flow abnormalities during the performance of a cognitive task.

Seventeen ME/CFS subjects [16 females, 1 male; average age (SD) 49.25 (11.43) years], and 16 HC [16 females; average (SD) age 49.60 (10.00) years] participated […] All ME/CFS subjects met the 1994 CDC Criteria and the 2003 Canadian Criteria for ME/CFS.

One ME/CFS and one HC participant were excluded from the analysis due to poor image quality, resulting in a final sample of 16 ME/CFS (15 women) and 15 HC. An independent ttest revealed no significant age differences between the groups (t(29) = 0.09, p = 0.93; Cohen’s d = .03). Mean (SD) duration of illness for ME/CFS subjects was 12.46 (9.27) years.

Mental fatigue was induced in all subjects using a modified version of the Paced Auditory Serial Addition Test (PASAT), which is a difficult cognitive task involving attention, working memory, and executive function

the PASAT, which is an auditory cognition task

Despite high levels of clinical fatigue, our fMRI study of ME/CFS patients did not demonstrate cerebral blood flow abnormalities at rest

As expected, the PASAT resulted in significant fatigue increases in both ME/CFS and HC subjects, which were associated with similar global as well as regional CBF changes in both groups. Interestingly, CBF increased over the first 3 min of the PASAT and then gradually returned to baseline over the next 9 min. This was particularly remarkable as task related fatigue steadily increased during the same time period. This discrepancy between fatigue and CBF changes seems to suggest that there were sufficient cerebral resources available in both groups to deal with the metabolic demands of this difficult task.

Overall, these data shed doubt on the essential role of widespread cerebral hypoperfusion in the etiology of ME/CFS. Rather, as we have previously demonstrated, abnormalities in functional interactions between fatigue-related brain regions may be better explanations

In essence, our results indicated that, in ME/CFS, fatigue and CBF to regions associated with task performance are strongly correlated. We speculate that ME/CFS patients may recruit more resources within the STG and cerebellum in order to maintain PASAT performance, a process associated with greater fatigue. When the PASAT ended and participants were allowed to recover, the same association between CBF and fatigue was detected, suggesting re-allocation of resources from areas involved in task performance correlated with better recovery. In contrast, HC participants showed a negative association between CBF and fatigue, suggesting greater blood flow to relevant areas may have produced more efficient, and therefore less effortful/fatiguing, task performance. This inverse association between CBF and fatigue was maintained during recovery, which may be suggestive of an active recovery process.

 

[Jonathan Edwards]

My reading of the study in the OP is that is quite strong negative evidence for any relevant defect on brain perfusion. The only differences found look to have been complicated subanalyses.