Wednesday, 6 December 2017

'Physical signs' to aid the diagnosis of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)?

I have to say that I wasn't completely au fait with the Perrin technique mentioned in the article by Lucy Hives and colleagues [1] or the exploration of whether "the five physical signs of the Perrin technique can assist in the screening of patients with CFS/ME, which could then subsequently lead to quicker treatment" but I was interested.

Interested because CFS/ME remains a condition diagnosed on the basis of observable symptoms. As a result, it is still subject to quite a few 'debates' on what the best fitting criteria might be (see here). Anything that might potentially help that diagnostic position is therefore welcomed. Indeed, anything that might provide something approaching an objective diagnosis could potentially open up a whole new world of treatment and intervention...

Accepting that talk of 'Perrin's point' "lymphatic drainage" and "the principle that toxins within fluid in the brain or spine column do not drain away as they should" are probably not everyone's cup of 'science' tea, the authors set about testing the Perrin technique for potentially diagnosing CFS/ME. Also whether "newly trained allied health professional (AHP) with no prior experience of CFS/ME" had the same diagnostic accuracy as more expert AHP. I'm not actually sure what specific disciplines those AHPs were actually following, but looking at the text - "One had 10 years of experience of using the Perrin technique and working with patients with CFS/ME (experienced AHP)" - and the affiliations of the authorship list (see here) - it looks to me like something between physiotherapy and osteopathy as a rough guess.

Approaching 100 participants were recruited for study - "52 patients with CFS/ME and 42 non-CFS/ME controls" - all adults and for those diagnosed with CFS/ME, all with "a prior formal diagnosis of CFS/ME at a National Health Service (NHS) hospital specialised clinic" and displaying various core features of CFS/ME (i.e. persistent fatigue and "the fatigue should feel worse after physical activity"). I note that they also required "a clear starting point to the fatigue." Assessments - "standard clinical neurological and rheumatological" - were also carried out and CFS/ME diagnosis was pitted (blind) against the Perrin technique. Indeed: "A priori, the Perrin technique required all five symptoms to be present for a patient to be diagnosed as CFS/ME." Not to copy too much text from the Hives paper, the five symptoms were: "(1) postural/mechanical disturbances of the thoracic spine... ; (2) breast varicosities... ; (3) tender Perrin’s point... ; (4) tender coeliac plexus... ; and (5) dampened cranial flow."

How did the Perrin technique do? Well, not bad at all: "Results show that, on average, the experienced AHP was most accurate (86%) at correctly diagnosing participants. This was followed by the newly trained who correctly diagnosed 77% and the physician who correctly diagnosed 69% of participants." I reiterate that the clinical team were "blinded to the groupings" (whether or not they were seeing a patient with CFS/ME or not).

Hives et al also provide some data on the specificity and sensitivity of the Perrin technique in relation to CFS/ME diagnosis, as well as some initial chatter about whether all the five symptoms together represent the most efficient grouping. They concluded that: "accuracy for both AHPs, overall, is highest when using only tests of tender coeliac plexus and postural/mechanical disturbance of the thoracic spine" potentially suggesting that "not all of the five physical signs may be necessary."

Whilst pretty interesting results, there is a need for further independent replication before anyone gets too excited about a possible objective test for CFS/ME. The authors similarly note that this was a straight 'yes you're diagnosed with ME/CFS' vs 'no diagnosis of CFS/ME' but also in future need to take into account other conditions potentially overlapping with CFS/ME such as fibromyalgia (FM) and whether the diagnostic waters are still so clear with such comparisons in mind. As I've mentioned in other posts (see here), the tendency in some quarters to conflate CFS/ME with 'chronic fatigue' also perhaps needs some further investigation too.

Still, there are reasons to be optimistic about the Hives findings. How, even alongside more traditional ways and means of diagnosing CFS/ME, the Perrin technique (in whatever form) *might* serve as a useful accompaniment to aiding the diagnostic process and perhaps even further distancing CFS/ME from the whole biopsychosocial model of disease (see here)...

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[1] Hives L. et al. Can physical assessment techniques aid diagnosis in people with chronic fatigue syndrome/myalgic encephalomyelitis? A diagnostic accuracy study. BMJ Open. 2017; 7: e017521.

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