Trial Report The presence of attentional and interpretation biases in patients with severe MS-related fatigue (also ME/CFS), 2024, Knoop, Moss-Morris et al

Brought to you by the Journal of Health Psychology, Kings College London. (in press)
I think this could be a good paper to look at, I suspect the investigators were disappointed that the chronic fatigue people did not look as different from healthy controls as the MS people did.

Oh, for goodness sake, look at that bias. They allow that pain is salient (definition of salient - noticeable, important). But the authors are suggesting that fatigue only becomes salient when someone has a chronic condition and has debilitating fatigue. What rubbish - fatigue in anyone is salient, because the body is sending a signal 'take note, you need a rest'. It's sort of tautological - the sensation of fatigue only exists when it is noticed, in the same way that pain only exists when it is noticed.

 

There are two parts to the study: Attention bias and interpretation bias. First, the attention bias:

Attention bias

Ugh. They really really don't get it, do they.

A Visual Probe Task (VPT)

24 pairs of fatigue-related words + neutral words; 24 pairs of activity-related words + neutral words. A pair of words appears on the screen, like this

Tired
+
Custard

And then the words disappear
and there is something like this:

<-
+

So, in that case, you are supposed to press c because the arrow points left, as opposed to m when the arrow points right. And the time it takes you to press the c or m is supposed to be related to how actively you were drawn to or away from the fatigue word or the activity word.

So, another example might be

Parsnip
+
somersaulting

followed by

->
+


The idea is that the attention of people with chronic fatigue is drawn towards the fatigue words (indicating hypervigilence) and away from the activity words (indicating fear avoidance), and so they will be looking or not looking at the place where the words were, and that will affect how quickly they respond to the arrow that appears where one word was.

I find it hard to believe that anyone thinks this exercise says anything about whether someone pays too much attention to the fatigue signals their body sends them. It seems laughable. They wrap it all up in fancy words - attentional behaviour and visual probe. But, it seems as scientific as a horoscope.

Here's the discussion about the lack of difference between people with ME/CFS and MS:

But, but, the authors cry, we know those ME/CFS people really do have attentional bias. The authors even admit that maybe their test isn't that great, because it isn't picking up the abnormality the they know is there.

As for the MS people:

Yep, they didn't look different to the healthy controls either.

Some more hand-wringing rationalisation:

Make of that what you will. Something about maybe physical activity isn't that scary for people with fatigue as the consequence comes later and fatigue isn't that bad. And something about a top-down cognitive process being at work, rather than a rapid bottom-up process - which they presumably think is not cognitive. Maybe we have to have more time to realise that we are afraid of running. They don't seem to know what is going on, but, despite the lack of evidence from their study, they just know that fear-avoidance perpetuates fatigue.

There is more avoidance going on with the authors refusing to face up to the fact that their prejudices are baseless than there is in both the ME/CFS and MS cohorts combined.

I wonder if patients really understood how the data was going to be used.

 

Although fear-avoidance has been found to play an important role in the perpetuation of fatigue,

Well it certainly has been endlessly asserted to have such a role. Which is a very different thing.

 

It's high time these people were stopped from playing silly psychological games with sick people, and, worse, drawing unwarranted conclusions from them. It's harmful, insulting and not good science.

 

Well, they do comment on reaction times obliquely, and the reaction times are reported in Table 2. For me, that would be one big and real result of the study.
Mean reaction time of the ME/CFS group was about 628 ms, regardless of what they were reacting to in the Attention bias game. Mean reaction time of the MS group was about 670. Mean reaction time of the healthy controls was about 528.

They found a measurable difference in reaction times between groups, and that is completely glossed over.

The way the game was set up, those peripheral vision issues and effect of fatigue on eyesight didn't matter, because mean reaction in and of itself, didn't matter. It was just the comparison between neutral words and the words supposedly triggering hypervigilance or avoidance.

(They also mention that they had a problem with their healthy controls,, with abnormally high rates of missed responses. They chucked out a substantial percentage of their healthy control data out because of this.)

 

People with everything to lose if the rest of the world learns how dodgy they are tend to try diverting the world's attention away from how dodgy they are.

 

Onto interpretation bias:

The problematic information processing biases are taken as a given in ME/CFS, with the aim being to compare and contrast.


Implicit Interpretation bias task

To summarise, for each of 12 ambiguous scenarios, participants had to rate how similar 4 sentences were to the scenario. One sentence put a positive interpretation on the scenario, one a negative somatic interpretation. The other two sentences were not designed to not be plausible representations of the scenario.

Here are the results:

Mean (and SD) of interpretations of all groups

Similarity rating................................... ME/CFS (n=40).................MS (n=156)................Healthy controls (N=46)

Similarity rating of positive interpretation....2.85 (0.42)................ 2.82 (046) ...................2.96 (0.50)
Similarity rating of somatic interpretation.....2.23 (0.52)............... 2.47 (0.57) ...................1.81 (0.38)
Similarity rating of positive foil ...................1.35 (0.32) ...............1.39 (0.40) ...................1.42 (0.36)
Similarity rating of negative foil...................1.18 (0.18) ................1.26 (0.25) ..................1.22 (0.24)

Values of statistical significance for result comparisons are not reported. Also, I'm not sure about the size of the MS samples - there were two MS samples. Is it possible they recruited more people in order to find some sort of a result?

Anyway. All three groups were equally likely to think a positive interpretation of the scenario was reasonable.

Both disease groups were more likely than healthy controls to think that a negative somatic interpretation of the scenario was reasonable, with the multiple sclerosis people rating those interpretations as more similar than the ME/CFS people. I don't think the ME/CFS results on this were significantly different from the healthy controls.
It is completely understandable and reasonable for the disease groups to rate a negative somatic interpretation as possible - they have had vivid personal experience of bodies not working well. But the difference is quite small.

And, it's such a huge leap in logic from there to 'manufacturing feelings of fatigue out of non-harmful normal body sensations'.

It would be laughable if people weren't actually paying attention to these investigators, and paying them to provide CBT sessions to cure people of their fatigue.

 

I do wonder about the informed consent - did participants really understand that the results would be used to try to label their fatigue as a product of attentional and interpretational biases?

I laughed about the comment about the welfare of animals. Because humans are animals and the authors have not considered the considerable harm that will flow from this study and its suggestion that people with MS can cure their fatigue by thinking differently about it.

And, as for the conflicts of interest, how can there not be a conflict of interest? The authors are in the business of providing CBT to fix false illness/symptom beliefs. And they did their best to find some false illness/symptom beliefs to fix.

That conflict of interest is plastered all over this study, including the way a lack of a difference between the ME/CFS participants and the healthy controls in so-called attentional and interpretational bias is minimised. Those findings for ME/CFS participants blow a giant hole in the basis for CBT to correct false-illness beliefs.