Cognitive Function Declines Following Orthostatic Stress in Adults With (ME/CFS), 2020, van Campen et al

Andy

Andy

Retired committee member
Introduction: Orthostatic intolerance (OI) is common among individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Cognitive dysfunction has been demonstrated during head-up tilt testing (HUT) in those with ME/CFS: worse scores on cognitive tests occur with increasing tilt angles and increasing complexity of the cognitive challenge. The aim of our study was to determine whether cognitive impairment persists after completion of HUT.

Methods and Results: Eligible participants were consecutive individuals satisfying criteria for ME/CFS who underwent HUT because of OI. The 2- and 3-back tests were performed before the start of HUT and within 5 min after completion of HUT. We measured the percentage of correct responses and raw reaction times before and after HUT for both the 2- and 3-back tests. We studied 128 ME/CFS patients who underwent HUT and had a complete set of N-back data before and after HUT. Compared to pre-tilt responses, the percentage of correct responses on the 2-back test decreased post-HUT from 77(18) to 62(21) and of the 3-back test from 57(17) to 41(17) (both p < 0.0001). The raw reaction time of the 2-back test increased post-HUT from 783(190) to 941(234) m/s and of the 3-back test from 950(170) to 1102(176) (both p < 0.0001). There was no difference in the N-back test data for subgroups dichotomized based on disease severity, the presence of co-morbid fibromyalgia, or the presence of postural orthostatic tachycardia syndrome.

Conclusion: As measured by the N-back test, working memory remains impaired in adults with ME/CFS following a 30-min head-up tilt test.
Click to expand...
Open access, https://www.frontiersin.org/articles/10.3389/fnins.2020.00688/full
 
So previous studies showed patients test performance declined during a head up tilt table test as the angle increased. This study tested before and within 5 minutes after the tilt table. Not surprisingly, the effect of the tilt table persisted during those 5 minutes. The conclusion seems to imply a much longer effect.

I wonder whether they have tested people with ME repeating the test without a tilt table. Cognitive fatiguability may lead to decline in performance on repetition of a cognitive task even without the additional orthostatic effects.
 
Last edited:
I thought this was an interesting study.

Among the limitations the authors noted are some significant ones:
No comparison with healthy controls was available. However, in the study of the N-back test in healthy controls during HUT was not different from the supine N-back test Medow et al. (2014).
Click to expand...

We only tested ME/CFS patients with a clinical suspicion of OI who underwent HUT. The N-back tests pre- and post-HUT in ME/CFS patients without OI symptoms need to be evaluated.
Click to expand...

We did not evaluate the length of time that cognitive testing remains abnormal following HUT, but this deserves further study.
Click to expand...
 
Using a visual 2- and 3-back test, this study shows that working memory is impaired shortly after orthostatic stress testing in ME/CFS patients, extending observations from previous small studies that working memory is impaired during orthostatic stress. Our results are consistent with the observation that PEM can start immediately after an orthostatic stress.
Click to expand...
Interesting study that throws up more questions than it answers. Real pity they didn't retest after a few hours or the next day.

I don't think the fact that they found impaired working memory just minutes after the HUT allows for the conclusion that this impairment is due to early PEM. It may just be that the brain needs a few minutes to recover from the reduced blood flow during the HUT and that a measurement 20 minutes later would have shown nothing.

To be clear, I wouldn't be at all surprised if orthostatic stress caused PEM - I rather suspect it does - it's just that this study doesn't show it because it only tested straight after the HUT.
 
Ravn said:
Interesting study that throws up more questions than it answers. Real pity they didn't retest after a few hours or the next day.

I don't think the fact that they found impaired working memory just minutes after the HUT allows for the conclusion that this impairment is due to early PEM. It may just be that the brain needs a few minutes to recover from the reduced blood flow during the HUT and that a measurement 20 minutes later would have shown nothing.

To be clear, I wouldn't be at all surprised if orthostatic stress caused PEM - I rather suspect it does - it's just that this study doesn't show it because it only tested straight after the HUT.
Click to expand...

From personal experience of a tilt table test:

“Despite the (Consultant’s letter saying I "was well on leaving", my 86 yo mother had to escort me out to father's car. I had been unable to speak to her for 5-10 mins when out from the tilt table test & still could not speak properly/word find for at least an hour afterwards. I had many symptoms whilst on the table (see letter in file) and yet Consultant found 'dysautonomia is not the cause of her symptoms'. “

I can confirm PEM started immediately (within minutes of the tilt) and continued, in varying degrees, for many days afterwards.
 
Mij said:
Are you referring to cognitive PEM?
Click to expand...

Yes.

I would have to look at my notes from the time, but I was extremely thirsty, had to hold the nurse’s arm to go back to the waiting room and was monosyllabic whilst I sat in the waiting room. I just wanted to go home, but needed to wait until I could stand and walk to the exit with mum.

As soon as we reached their home (30-40 mins after tilt ended), I went to bed and was still struggling to speak a complete sentence after a couple of hours.
 
You must log in or register to reply here.
Back
Top Bottom