1. Patients launch $1.27 million crowdfunding campaign for ME/CFS gut microbiome study.
    Check out the website, Facebook and Twitter. Join in donate and spread the word!
ME/CFS: In Free Fall Through the Looking Glass
Jody Smith continues to try to put into words the horror of the altered state that hobbles the brains of those with ME/CFS...
Discuss the article on the Forums.

Cognitive Functioning in People With CFS: A Comparison Between Subjective and Objective Measures

Discussion in 'Latest ME/CFS Research' started by Bob, Dec 25, 2013.

  1. Bob

    Bob

    Messages:
    8,044
    Likes:
    10,274
    England, UK
    Cognitive Functioning in People With Chronic Fatigue Syndrome: A Comparison Between Subjective and Objective Measures.
    Cockshell SJ, Mathias JL.
    Neuropsychology. 2013 Dec 23. [Epub ahead of print]
    http://www.ncbi.nlm.nih.gov/pubmed/24364389/?ncbi_mmode=std

    Abstract
    Objective: The purpose of this study was to examine the relationship between subjective and objective assessments of memory and attention in people with chronic fatigue syndrome (CFS), using tests that have previously detected deficits in CFS samples and measures of potential confounds. Method: Fifty people with CFS and 50 healthy controls were compared on subjective (memory and attention symptom severity, Cognitive Failures Questionnaire, Everyday Attention Questionnaires) and objective (California Verbal Learning Test, Rey-Osterreith Complex Figure Test, Paced Auditory Serial Addition Test, Stroop task) measures of memory and attention. Fatigue, sleep, depression, and anxiety were also assessed. Results: The CFS group reported experiencing more cognitive problems than the controls, but the two groups did not differ on the cognitive tests. Scores on the subjective and objective measures were not correlated in either group. Depression was positively correlated with increased severity of cognitive problems in both the CFS and control groups. Conclusions: There is little evidence for a relationship between subjective and objective measures of cognitive functioning for both people with CFS and healthy controls, which suggests that they may be capturing different constructs. Problems with memory and attention in everyday life are a significant part of CFS. Depression appears to be related to subjective problems but does not fully explain them. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
    Izola and Jarod like this.
  2. MeSci

    MeSci ME/CFS since 1995; activity level 6

    Messages:
    3,487
    Likes:
    4,075
    Cornwall, UK
    It would be good to see the full paper to see for example how the people with CFS were diagnosed, and other selection criteria. At least the authors acknowledge that
    I wonder what these 'different constructs' are that they refer to.
    Izola likes this.
  3. Bob

    Bob

    Messages:
    8,044
    Likes:
    10,274
    England, UK
    Yes, agreed. From the abstract wording, it doesn't look like they set out to disprove that ME patient have objectively measured cognitive dysfunction. It's a single paper, so it doesn't mean much on it's own, but it would be interesting to read it.
    It seems that they haven't attempted to measure post-exertional cognitive dysfunction.

    The authors published this paper, earlier in the year, with different conclusions:
    If I recall correctly some studies have shown that only certain aspects of cognition are dysfunctional, such as processing speed, as in the above and below papers, and perhaps only for complex tasks (multi-tasking?) as the below paper shows. So I wonder if this latest study repeated the same tests, to assess processing speed for complex tasks.

    Here's a recent paper that shows that processing speed is a problem for complex tasks:



    Here's quite a comprehensive 2013 review of cognitive deficits in ME/CFS patients, but Lenny Jason and others (I haven't read it in full yet):

    Cognitive impairments associated with CFS and POTS
    Lindzi Shanks, Leonard A. Jason, Meredyth Evans, and Abigail Brown
    Front Physiol. 2013; 4: 113.
    Published online 2013 May 16. doi: 10.3389/fphys.2013.00113
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655280/
    Last edited: Dec 26, 2013
  4. wdb

    wdb Admin

    Messages:
    829
    Likes:
    577
    London
    So if I'm interpreting this right the good news is that yet again subjective measures have been shown to be 100% worthless as a measure of incapacity. The bad news is this might be taken to demonstrate CFS patients subjectively overestimate the severity of their cognitive impairments. I think a more likely explanation might be that like physical impairments stamina is the issue so a relatively short cognitive test might not be sufficient to differentiate between the groups.
    WillowJ, Izola, aimossy and 3 others like this.
  5. MeSci

    MeSci ME/CFS since 1995; activity level 6

    Messages:
    3,487
    Likes:
    4,075
    Cornwall, UK
    I agree. Personally I find that my cognitive function varies in a similar way to physical function. Some days it is really good and barely slowed at all. On bad days it's not just slowness but an almost complete inability to think. What causes both physical and cognitive fatigue for me is almost entirely PEM and/or the wrong food.
  6. Bob

    Bob

    Messages:
    8,044
    Likes:
    10,274
    England, UK
    Also, some studies have shown that speed of processing in complex tasks is abnormal, whereas all other cognitive tasks have been assessed to be normal. So it would be interesting to see if they tested this specific issue in the latest study.

    Also, did they plot cognition vs effort? Perhaps if ME patients apply extraordinary effort to their cognitive tasks then the cognitive deficits are not so obvious, when objectively measured. But they are obvious subjectively, because of both the extra effort needed to get results, and also because of the pay-back and extra exhaustion experienced afterwards.
    Last edited: Dec 26, 2013
    NK17 and Valentijn like this.
  7. alex3619

    alex3619 Senior Member

    Messages:
    7,178
    Likes:
    11,229
    Logan, Queensland, Australia
    I can look really smart to a psych: what, you have cognition problems?

    Yet I have times when I cannot figure out how to read, or open a plastic bag. I am really not sure they have a good grasp on what to test for.
    Dolphin, NK17, Koan and 6 others like this.
  8. Sean

    Sean Senior Member

    Messages:
    1,214
    Likes:
    1,961
    At least these issues are starting to be explicitly discussed in the peer reviewed literature. An important step forward, albeit long overdue, and with many more left to take.

    But it is a start.
    WillowJ, Dolphin and Bob like this.
  9. Bob

    Bob

    Messages:
    8,044
    Likes:
    10,274
    England, UK
    Beth Unger is testing for post-exertional cognitive deficits (using online tests) in the large CDC study, for 48 hours after the one-day exercise test. But I don't know if they are testing for processing speed during complex tasks. Probably not, knowing the CDC.
    taniaaust1, Valentijn and Simon like this.
  10. Snow Leopard

    Snow Leopard Senior Member

    Messages:
    2,296
    Likes:
    1,755
    Australia
    Studies like this can be biased in that patients of above average intelligence are significantly more likely to participate.

    So the results can be a result of apples vs oranges.

    The other issue is that of fatigablity. A short battery of tests won't reveal the same differences as if you expected patients to do 8 hours of tests in one day. The difficulty is that if you ask patients to do that, many will decline, which is why studies like this are easily biased.
    Dolphin, NK17, Valentijn and 2 others like this.
  11. Snow Leopard

    Snow Leopard Senior Member

    Messages:
    2,296
    Likes:
    1,755
    Australia
    Was this different to this study?
    http://www.ncbi.nlm.nih.gov/pubmed/23527651

    Same number of patients and controls, but they found :
  12. MeSci

    MeSci ME/CFS since 1995; activity level 6

    Messages:
    3,487
    Likes:
    4,075
    Cornwall, UK
    Different study, same authors. I wonder which kinds of memory they tested? There is short-term, long-term, procedural, etc. Different conditions (e.g. types of dementia) affect different types of memory at different stages, IIRC, so it's important to be specific when reporting research findings.
  13. SOC

    SOC Moderator and Senior Member

    Messages:
    5,286
    Likes:
    6,275
    USA
    If I'm reading the title of this paper correctly and assuming that they titled their paper appropriately (Cognitive Functioning in People With Chronic Fatigue Syndrome: A Comparison Between Subjective and Objective Measures), this study was not about us, but about the efficacy of subjective vs objective tests. The authors clearly understand that we have cognitive problems (impaired processing speed, in particular) based on their earlier publication.

    So isn't the point of this paper that subjective tests of cognitive dysfunction suck raw eggs?
    Last edited: Dec 27, 2013
    alex3619 and Bob like this.
  14. Simon

    Simon

    Messages:
    1,336
    Likes:
    4,202
    Monmouth, UK
    Brief commentary on the abstract

    I blogged about Susan Cockshell's impressive earlier work, 'Brain fog: The Research' which includes a meta-analysis (covering 1,500 CFS patients)
    I think those are two important conclusions.

    I think it's more complex that that. Lab tests of cognitive functioning are very narrow and very artificial.

    Take the example of the Stroop test, used in this study and one of the most common cognitive function tests there is. The simplest way to see how it works is just to look at the two lists below.
    Don’t read them, instead say out loud the color each word is displayed in, as quickly as you can.

    [​IMG]
    Not so easy… (Try it online)

    Exactly how the Stroop test relates to real-world functioning isn't clear - and that's what the authors mean when they say:
    On top of the relevance of the test there are 2 other issues.
    • Fatigability as @Snow Leopard says where you may need repeated testing to reveal problems
    • Stress testing, as @Bob mentioned
    A fMRI brain study found that CFS patients perform as well as controls but activate more brain regions in the process, ie working harder to get the same result. Repeat tests may well find a difference emerge over time (there were hints of this in Susan Cockshell's earlier work)

    In my view, stress testing could well be cognitive,not just physical but the point is the same: stressing patients to reveal differences between patients and controls that may not be apparent on simple tasks. Multi-tasking might be another way of doing this.

    Also, judging by other comments on this thread some people are hit much harder by physical fatigue than mental fatigue and these people might not show so much difference on cognitive tests. Also, if mecfs is multiple diseases, a sample of 50 is likely to be a mixed bag of different patients....

    will try to get the full text later
    WillowJ, Dolphin, NK17 and 6 others like this.
  15. Bob

    Bob

    Messages:
    8,044
    Likes:
    10,274
    England, UK
    Yes, and even in this abstract they categorically state:
    "Problems with memory and attention in everyday life are a significant part of CFS."

    I think it's difficult to be sure about the full nature of this study without reading the full paper.

    On the one hand they say that subjective and objective measures don't correlate in either patients or controls, which is very helpful information: "Scores on the subjective and objective measures were not correlated in either group."

    But then they say that CFS patients' cognitive test results are no different to controls, despite reporting more cognitive problems (which seems to contradict their earlier study):
    "The CFS group reported experiencing more cognitive problems than the controls, but the two groups did not differ on the cognitive tests."
    Last edited: Dec 28, 2013
    Valentijn, Simon and SOC like this.
  16. Hip

    Hip Senior Member

    Messages:
    2,936
    Likes:
    2,753
    Just posting the Cognitive Failures Questionnaire for reference purposes:

    Reference:
    Broadbent, D.E., Cooper, P.F., FitzGerald, P., & Parkes, K.R. (1982). The Cognitive Failures Questionnaire (CFQ) and its correlates. British Journal of Clinical Psychology, 21, 1-16.

    Last edited: Dec 27, 2013
    NK17 and Simon like this.
  17. Hip

    Hip Senior Member

    Messages:
    2,936
    Likes:
    2,753
    In my own personal experience of my ME/CFS, I find it quite hard to provide an accurate subjective grading of my own cognitive dysfunction and overall ME/CFS symptoms, in any absolute sense.

    I am always able to say whether I am better or worse than yesterday (which is a relative measure of cognitive dysfunction). But on any given day, I could not easily place myself on an absolute scale (from 1 to 10 say) of how I was feeling.

    This is party because my long term memory is appalling, so I very quickly forget how I was feeling last week and last month, which makes it hard to gauge in absolute terms how I am feeling on any particular day. But I can remember how I was feeling yesterday, and so it is easy for me to say whether I am feeling better or worse than yesterday.

    I see this as a bit of a problem, because it makes it hard for me (and no doubt other ME/CFS patients) to judge whether a given medication regimen is having beneficial effects or not.

    However, what I tend to do is use natural objective measures of my heath level. For example, by noting how many days per week I need to stay in bed for 18 hours a day or more. Or I might note how many times I tend to leave the house per week (the healthier I am , the more I tend to go out). Or I might note just how much complex reading or writing I was doing. I seem to be able to remember these more objective details. If these more objective measures of my heath level indicate an improvement, then I feel more confident that my current regimen is doing me good.
  18. SOC

    SOC Moderator and Senior Member

    Messages:
    5,286
    Likes:
    6,275
    USA
    This is exactly my experience, too.
    MeSci likes this.
  19. alex3619

    alex3619 Senior Member

    Messages:
    7,178
    Likes:
    11,229
    Logan, Queensland, Australia
    What does it mean if you have very often or quite often for almost all if the questions? :D
  20. jeffrez

    jeffrez Senior Member

    Messages:
    1,108
    Likes:
    638
    NY
    :rolleyes:

    They must have had some pretty dumb controls.

    Iow, what this abstract is saying is that whatever cognitive problems people with CFS report are "all in their heads," and that any cognitive problems that do actually exist are because of depression.

    :rolleyes:

See more popular forum discussions.

Share This Page