Can physical assessment techniques aid diagnosis in people with CFS/ME? A diagnostic accuracy study, 2017, Perrin et al

Discussion in 'ME/CFS research' started by Andy, Oct 27, 2017.

  1. Andy

    Andy Committee Member

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    Seems to be an attempt to prove the worth of the Perrin technique? I've put this in the biomed forum for now but obviously it can be moved if need be.

    Restricted access at http://clok.uclan.ac.uk/20386/

    ETA: Open access now available at http://bmjopen.bmj.com/content/7/11/e017521
     
    Last edited: Nov 14, 2017
  2. Invisible Woman

    Invisible Woman Senior Member (Voting Rights)

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    and


    Perrin technique aside - we have no way of knowing what criteria were actually used to diagnose these patients. If the second quote literally means that a single physician was used to confirm the diagnosis it just means that they fit this individual's idea of what ME is.

    Bolding is mine - Showing agreement with current diagnostic techniques doesn't inspire me with confidence. As far as I am aware the current diagnostic techniques aren't that great and this piece doesn't mention any tests to rule out other conditions. I don't have a whole lot of faith who don't understand that accurate diagnosis is a major issue with this disease.
     
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  3. Trish

    Trish Moderator Staff Member

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    ''A physician conducted a standard clinical neurological and rheumatological assessment, whilst looking for patterns of illness behaviour. Each examination lasted approximately 20 minutes.''

    ''There was however, a significant bias in the diagnosis made by the physician relative to actual diagnosis, (p<0.001), indicating poor diagnostic utility of the clinical neurological and rheumatological assessment. ''

    Am I reading this correctly. Is this saying the physician's diagnoses didn't fit with the 'actual diagnosis'.

    Since diagnosis of ME is normally done by listening to the patient's description of history and symptoms, I'm not surprised the physician didn't get the diagnosis from examining and observing the patient - it sounds like they weren't allowed to ask any questions, just do some irrelevant observations. No wonder they got the diagnosis wrong.

    Was this all designed to make the Perrin technique look good by comparison? Does anyone know what the coeliac plexus or the Perrin point are? And is there any theoretical basis that might lead to them being useful diagnostically?
     
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  4. Andy

    Andy Committee Member

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  5. Snowdrop

    Snowdrop Senior Member (Voting Rights)

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  6. Invisible Woman

    Invisible Woman Senior Member (Voting Rights)

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    Well they do say:
    Bolding mine - what does that mean?
    A) the patient says "Ouch" when I press this area
    or
    B) in answer to the physician's questions the patient clearly exhibits illness behaviour

    Very vague. Which is why we need adherence to properly defined criteria. I suspect it suits many a "researcher" not to have to bother with tightly defined criteria.
     
  7. Trish

    Trish Moderator Staff Member

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    I'd guess that in order to test the Perrin diagnostic techniques which don't involve talking (except possibly ouch), they decided to use as a control a physician carrying out irrelevant rheumatology and neurology tests without talking to the patient. In both groups they could at the same time observe 'illness behaviour'.

    The 'actual diagnosis' used to check validity would have been the diagnosis they entered the study with, presumably from the CFS clinic that referred them, so could be anything.
     
  8. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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    Your second quote more or less answers the first but also, bear in mind that in normal practice the AHPs would take an extensive verbal history in addition to the physical examination.

    Edited to add: as someone who has been to a Perrin practitioner, I always wondered what weight was given to the physical examination versus history. I'm looking forward to seeing the full details of this study.
     
  9. Andy

    Andy Committee Member

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  10. Andy

    Andy Committee Member

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  11. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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  12. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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  13. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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    I haven't found any reason for this yet in the paper and I'm not able to read all of it just now but, anecdotally, I know that Dr Perrin believes that people who develop ME (or CFS, as he himself prefers) do so in part because they are anatomically susceptible and that relatives are likely to exhibit the same anatomical features, even if they currently show no signs of the illness.
     
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  14. Valentijn

    Valentijn Guest

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    So it is completely focused on the Perrin stuff, which gives it a rather promotional slant:
    They used NICE criteria for diagnosis, so it's not particularly clear if PEM was a mandatory symptom. Patients were also "assessed" for ICC criteria, but it doesn't sound like it was mandatory to qualify for an ICC diagnosis. Some of the exclusionary criteria are a bit questionable, such as autoimmunity and especially neurological disorders. It would imply that they are approaching ME as being a vague fatigue disorder instead of something which has been categorized as a neurological disease.

    The assessment process sounds pretty vague and quackish, basically looking for an abnormal posture and tender points. I'd imagine those are present in many diseases. Cranial Rhythmic Impulse seems to be something also quite vague regarding how to assess it, though it's claimed that it "expresses unresolved conditional forces and patterns within the system", such as from "unresolved trauma or toxins":
    Lack of training is very relevant, since it probably takes some time to understand how to apply the bullshit:
    They're comparing their method to something quite useless, presumably to make the Perrin stuff look better:
    83% of patients were female, but only 40% of controls. So diagnosis could be guessed with a decent rate of accuracy simply based on gender. Perrin practitioners in general correctly "diagnosed" more patients, but had a false positive rate of 14-17%. The physician had no false positives. I suspect the Perrin rate of a false positive misdiagnosis would be astronomical if the controls were another group of patients with a different diseases, though it's already very high is this study to begin with.

    It's also difficult to generalize the diagnostic capabilities of the three groups, since there was only one member from each:
    This is research quackery on par with the SMILE trial, just a bit less offensive because it doesn't assume ME is psychosomatic. I'd rate it 4 ducks out of 5: :emoji_duck::emoji_duck::emoji_duck::emoji_duck:
     
  15. Trish

    Trish Moderator Staff Member

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    I noticed both these factors too.

    And the patients were recruited by volunteering. So who's to say Perrin himself or one of his minions didn't prompt their own patients, who they would recognise, to volunteer. Not saying they did...

    And they assessed by 5 'techniques', but since the same assessor did all 5, what they decided for one technique would have influenced their assessment on the others. One of the techniques of the Perrin people was feeling for swelling (Edit:and tenderness) in lymphatics, and a well known recognised symptom of ME in many patients is swollen tender lymph nodes, so maybe that's all they were finding.

    Not good science.
     
  16. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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    It's at worse "the fatigue should reduce the amount of physical activity each person could do and the fatigue should feel worse after physical activity" or at best "symptoms getting worse after physical or mental exertion". NICE diagnostic criteria certainly aren't ideal but they could be lot worse.
    As always, say what you really think!
    But the NHS physician has experience of ME/CFS, too. Don't they control for 'validity' of the Perrin Technique?
    Yes, but that's true for the NHS physician, too.
    That's harsh, isn't it? There aren't any magic circles in this one.
     
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  17. Valentijn

    Valentijn Guest

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    The limitations on the physician were pretty silly, limiting them to a brief physical exam. That isn't how the NHS diagnoses ME/CFS.

    The Perrin practitioners were probably involved in running the study, so likely knew a lot more about what was going on.
     
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  18. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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    No, but surely that isn't the point. It isn't the accuracy of NHS physical examinations that were being tested.
    Isn't that the point. The NHS were involved in it too and knew what was going on.
     
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  19. Scarecrow

    Scarecrow Senior Member (Voting Rights)

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    I'm not arguing that there was no bias. I bet the NHS expected a null result for the Perrin Technique and that's why they agreed to be involved.

    Which sort of does bring us back to SMILE. Did Crawley ever imagine that there would be a 'positive' result for SMILE? Does she realise that it was due to study design?
     
    Last edited: Nov 14, 2017
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  20. John Mac

    John Mac Senior Member (Voting Rights)

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    I was one of the ME patients in this study and was very impressed by how the Perrin practitioner was able to quickly home in on the sore lymph nodes that they say is characteristic of ME. I already knew of one of the points from attending a lecture by Dr Perrin about 5 years earlier however the other 4 sore lymph nodes I didn't even know I had until she pressed on them.

    The NHS Physical Therapist who examined me and was presumably given some training in the technique was pretty useless, I had to ask her to go over areas again until she found the same sore lymph nodes.

    I know a lot of people think this is all quackery but I think you should separate the treatment (and possibly a money making scheme) from this which is a physical examination to screen for ME.
    Does anybody know of any other physical exam or blood test to diagnose ME?
    I think there is a danger of throwing the baby out with the bath water.
     
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