Differentiating Psychosomatic, Somatopsychic, Multisystem Illnesses and Medical Uncertainty, 2019, Bransfield, Friedman

[Sly Saint]

Abstract
There is often difficulty differentiating between psychosomatic, somatopsychic, multisystem illness, and different degrees of medical uncertainty. Uncommon, complex, and multisystem diseases are commonly misdiagnosed.

Two case histories are described, and relevant terms differentiating psychosomatic, somatopsychic, and multisystem illnesses are identified, reviewed, and discussed. Adequate differentiation requires an understanding of the mind/body connection, which includes knowledge of general medicine, psychiatry, and the systems linking the body and the brain. A psychiatric diagnosis cannot be given solely based upon the absence of physical, laboratory, or pathological findings.

Medically unexplained symptoms, somatoform disorder, and compensation neurosis are outdated and/or inaccurate terms. The terms subjective, nonspecific, and vague can be used inaccurately. Conversion disorders, functional disorders, psychogenic illness, factitious disorder imposed upon another (Munchausen’s syndrome by proxy), somatic symptom disorder, psychogenic seizures, psychogenic pain, psychogenic fatigue, and delusional parasitosis can be over-diagnosed.

Bodily distress disorder and bodily distress syndrome are scientifically unsupported and inaccurate.
Many “all in your head” conditions may be related to the microbiome and the immune system. Better education concerning the interface between medicine and psychiatry and the associated diagnostic nomenclature as well as utilizing clinical judgment and thorough assessment, exercising humility, and maintaining our roots in traditional medicine will help to improve diagnostic accuracy and patient trust.

https://www.mdpi.com/2227-9032/7/4/114/htm

 

[Sly Saint]

Brain–body diagnostic errors are common in these patients, and these errors receive considerable attention in both the media and in the medical literature. Most of the cases receive this attention in books, media, and journal articles and involve erroneous psychiatric diagnoses rather than medical diagnoses [17,18].
Females are more often given an incorrect psychosomatic diagnosis, indicating gender-based bias and lack of research/understanding on how the female body responds to biological illness [19].

Illnesses such as chronic fatigue syndrome and fibromyalgia are “contested” illnesses. They are considered psychosomatic and not “real” illnesses. They are given labels such as “hysteria”, “hypochondriacal”, or “all in their head” [19].

Difficult-to-diagnose cases are often viewed as invisible illnesses, since there may be no outward appearance of illness by a superficial examination. Many people suffering from these chronic, invisible illnesses such as myalgic encephalomyeletis/chronic fatigue syndrome, fibromyalgia, Lyme disease, and postural orthostatic tachycardia syndrome (POTS) are frequently misdiagnosed. They are tired of being unheard and told symptoms are imaginary, self-inflicted, and psychosomatic. As a result of this, they often describe feelings of abandonment from physicians and the healthcare system, which results in increased risks of suicidal ideation, suicide attempts, and suicide compared with the general population [29].

Flawed guidelines have resulted from flawed research and bias. This problem is further compounded when well-intentioned physicians follow these guidelines assuming they are trustworthy. Examples of this have occurred with myalgic encephalomyelitis/chronic fatigue syndrome, Lyme disease, and “medically unexplained symptoms.”

A lack of understanding of myalgic encephalomyelitis/chronic fatigue syndrome both prior to and after the Institute of Medicine Report on this disorder has contributed to many patients feeling maligned, blamed, untreated, and undertreated. Some patients stated that they felt belittled, dismissed, and ignored by their health care professionals who followed some of the commonly disseminated guidelines. More than 80% of patients with myalgic encephalomyelitis/chronic fatigue syndrome (CFS) go undiagnosed, while 65% of patients spend more than a year seeking the correct diagnosis [31,32,33,34]. Treatment recommendations based upon a graded activity and a cognitive behavioral therapy (PACE) trial were previously adopted by many healthcare organizations. However, the research was highly flawed and never supported the belief that ignoring symptoms would lead to recovery [35,36]. The inaccurate treatment recommendations based upon the PACE trial recommended patients should ignore symptoms. In addition, patients were given a form of cognitive behavior therapy that challenged their beliefs of their having any physiological illness limiting their ability to exercise. Instead, to become more active—and possibly fully recover—they only needed to ignore their symptoms [37].

Many patients failed to respond to this treatment, and the research supporting the concept that exercise can treat chronic fatigue syndrome was subsequently rejected by Cochrane stating that the work does not meet the organization’s “quality standards.” [38]. After the PACE study was found to be invalid, there have been further advances in the field, and many guidelines have since been revised [39].

 

[duncan]

Friedman you all know. Bransfield is a former President of ILADS, so he is fairly prominent in the Lyme community, at least on the psych side. He is sort of like B Fallon of Columbia U -also a psych - in that regard.

 

[Arnie Pye]

Somatopsychic - is this a new word for doctors to use when dismissing their patients? I've never heard it before.

 

[Anna H]

"In the definition of bodily distress syndrome, there is a group of conditions that have little in common other than being distressing to deal with by some physicians. This group includes chronic fatigue syndrome (ME/CFS), fibromyalgia, irritable bowel syndrome, chronic pain syndrome, hyperventilation syndrome, non-cardiac chest pain, and somatoform disorder. What these conditions are considered to have in common is the belief that there is a central sensitization syndrome, which is not supported by any neurophysiological evidence.

In addition to this deficiency, there is a failure to be scientifically defined as a diagnostic category, and from an evidence-based medicine perspective, it fails to establish that it excludes patients with medical conditions that require medical care. The flaws in the concept of bodily distress disorder and bodily distress syndrome are like the flaws that were revealed in the PACE study: Labeling patients in this manner results in poor treatment outcomes [125,126].

Allen Frances, Chair of the DSM-IV Task Force, stated that bodily distress disorder in the ICD-11 is a "bad mistake because it: (1) will mislabel as mentally ill millions who have normal health worry; (2) allows docs to assume ‘It’s all in your head’; (3) encourages inadequate medical testing/diagnosis; (4) weak research; (5) wide patient opposition; 6) repeats DSM error” [127].


Since neither bodily distress disorder nor bodily distress syndrome are included in the DSM-5, and there is no indication it will ever be recognized as a valid diagnosis by the American Psychiatric Association, it poses a somewhat lesser threat to patients in the United States. Its inclusion in ICD-11, however, can particularly impact other countries.

There may be a motivation to label patients with bodily distress disorder with a belief it will reduce short-term healthcare costs. Instead, it may have a long-term adverse effect upon the health of tens of millions of suffering patients across the globe, which makes it a concern for ethics as well as science [125]."

 

[Anna H]

Somatopsychic - is this a new word for doctors to use when dismissing their patients? I've never heard it before.

Me neither. It's explained as:

"Somatopsychic disorders are mental disorders caused or exacerbated by somatic disorders. In contrast to psychosomatic disorders, the list of somatic conditions causing mental disorders keeps expanding as scientific knowledge advances. Many general medical conditions are recognized as causing psychiatric symptoms. Endocrine disorders, tumors, autoimmune disorders, and infections are particularly associated with causing psychiatric symptoms."

Apparently it's a term that's being used:

Differential diagnosis of somatopsychic disorders
Abstract
A substantial number of patients who present with psychiatric symptoms are suffering from underlying or unrecognized medical illnesses. Only by an awareness of differential diagnostic factors and a high index of suspicion can the clinician avoid misdiagnosis and inappropriate treatment of these somatically ill patients. The authors discuss some of the general characteristics that can help differentiate medical illness from primary psychiatric illness, and outline the psychiatric findings commonly associated with a number of physical illnesses.

https://www.sciencedirect.com/science/article/abs/pii/S0033318279707961

Hyper and hypothyroidism came to mind, both able to cause anxiety if untreated.
Not sure if a specific term is needed for this, but it doesn't seem dismissive of patients.

Edit :spelling, ETA

 

[rvallee]

Some good points made here. But the situation is much simpler than people make it out to be. It's not "difficult" to differentiate, it's impossible. Even the most "eminent" experts on psychosomagic illness cannot make the difference and only argue out of lack of evidence mixed in with personal beliefs that are frankly bizarre to the point of being delusional.

No one can tell the difference. It is a category error that has systematically failed and will continue to produce nothing but failure. When no one can tell with any certainty whether something belongs in a category, this category simply does not exist. Accept it and move on.

One thing I dispute:

Adequate differentiation requires an understanding of the mind/body connection

We can't differentiate. Enough of this. There is no doubt anymore. We don't know anything about this "connection". We are seeing the equivalent of a smooth surface because we are too far away, when zooming in would show how amorphous and textured the thing that looks smooth from afar definitely is not.

In the definition of bodily distress syndrome, there is a group of conditions that have little in common other than being distressing to deal with by some physicians.

This is a salient point. The "distress" that is so often cited in research papers is not ours, it is the physicians'. We do not have any particular distress, it is exactly the same as the "distress" anyone would have at being sick. In truth, it's actually about limitations and their consequences. Illness causes distress because it is limiting, not the other way around.

I would even argue that much of the anxiety is also the physicians' and is largely a misdiagnosis. I don't really see why a self-report of anxiety should be taken as fact when the same would not be accepted of a fever. We cannot measure anxiety and only have a vague, malleable, definition of it and as a result it is overdiagnosed a minimum of 10x over, if not 100x.

At least this is a discussion in the right direction and it's good to see competent discussion of the problems with the literature. It's going to be one hell of a hangover for the people who bet everything on this magical psychology. There are currently zero concerns for even the possibility that it could be a mistake, the very idea is laughed off as preposterous. This is dangerous in any field and completely irresponsible in medicine.

Applying funding + effort + time will solve those problems. This has simply not been tried yet, those diseases are all underfunded and maligned, none of them have been targeted by a deliberate strategy free of the usual sabotage from people who see psychomagic everywhere. Zero surprise they have not seen any progress.

 

[Arnie Pye]

Hyper and hypothyroidism came to mind, both able to cause anxiety if untreated.

Personal anecdote : Anxiety is a common effect of hypothyroidism, and so is poor gut health. As a result of this, absorption of nutrients is often poor and so levels of nutrients are often low. I'm hypothyroid. Treating my hypothyroidism had little impact on my anxiety, but optimising my poor iron and ferritin levels did. There have been further improvements in my overall health, both physical and mental, since optimising other low nutrients. I wouldn't describe myself as anxious any more, and I'm rarely depressed.

 

[Anna H]

Personal anecdote : Anxiety is a common effect of hypothyroidism, and so is poor gut health. As a result of this, absorption of nutrients is often poor and so levels of nutrients are often low. I'm hypothyroid. Treating my hypothyroidism had little impact on my anxiety, but optimising my poor iron and ferritin levels did. There have been further improvements in my overall health, both physical and mental, since optimising other low nutrients. I wouldn't describe myself as anxious any more, and I'm rarely depressed.

Great to hear that you feel better!
I also have hypothyroidism and had unusually high anxiety before getting diagnosed.
Optimized nutrition I agree is very valuable to improve one's well being.

 

[alex3619]

No one can tell the difference. It is a category error that has systematically failed and will continue to produce nothing but failure.

Exactly.

 

[Dx Revision Watch]

(Expand to display my highlighting)

3.2.16. Bodily Distress Disorder, Bodily Distress Syndrome
Bodily distress disorder is closely related to bodily distress syndrome. Neither are included in any edition of the APA DSM or in the ICD-10. The medically unexplained symptoms criteria for somatoform disorder have been criticized for being unreliable, since they define a disorder based on the absence of identifying features rather than the recognition of a problem [119]. In the transition from somatoform disorder to somatic symptom disorder, the most significant change was the removal of the invalid distinction between medically explained and medically unexplained somatic complaints. A group of proponents in Europe salvaged the diagnostic category with a substitute phrase and were able to have it listed in the proposed ICD-11 (6C20). These proponents renamed it bodily distress disorder and replaced the medically unexplained criteria with the concept of long-standing excessive distress and excessive thoughts, and behaviors towards pain that are considered of either known or unknown etiology [120]. In contrast, bodily distress syndrome is associated with excessive thoughts and behavior that are considered of unknown (medically unexplained) etiology [120,121].

Note that the ICD-11 Bodily distress disorder (BDD) diagnosis can be applied not just to pain as a symptom (where it mirrors the ICD-10 F45.4 Persistent somatoform pain disorder as one of the ICD-10 F45.x categories which BDD subsumes and replaces), but to any symptom or to multiple symptoms:

ICD-11:

https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/767044268

"Typically, bodily distress disorder involves multiple bodily symptoms that may vary over time. Occasionally there is a single symptom—usually pain or fatigue—that is associated with the other features of the disorder."

The authors go on to state: In contrast, bodily distress syndrome is associated with excessive thoughts and behavior that are considered of unknown (medically unexplained) etiology [120,121].

This sentence doesn't make any sense to me and reads as though some words may have been inadvertently omitted.

However, Bodily distress syndrome (BDS) does not require "excessive thoughts and behavior" to meet the BDS diagnosis. The BDS diagnosis is made solely on the basis of "medically unexplained" physical symptom patterns or clusters, and their complexity and duration, that result in significant distress or impairment to daily life.

Whilst emotional or behavioural responses to symptoms may be considered by Fink et al to be commonly associated with BDS and may be considered by Fink et al to be important for treatment, "excessive thoughts" or behavioural responses are not a requirement and do not form part of the criteria.

Since one of the references (at 121) given for this statement is my co-authored document: Comparison of SSD, BDD, BDS, BSS in classification systems Version 1 | July 2018:

121. Dx Revision Watch. Available online: https://dxrevisionwatch.files.wordp...-bdd-bds-bss-in-classification-systems-v1.pdf (accessed on 30 June 2019).

I am concerned that the authors have incorrectly cited "excessive thoughts and behavior" as being a key feature of the BDS construct.


I would also challenge the authors' statement: "Bodily distress disorder is closely related to bodily distress syndrome."

Both the World Health Organization (WHO) and Professor Per Fink² have clarified that as defined for ICD-11, BDD is a conceptually different diagnosis. ICD-11's BDD and Fink’s BDS are differently characterized, have very different criteria and include a different patient set.

ICD-11's Bodily distress disorder is closer conceptually and in required features to DSM-5's Somatic symptom disorder.

2 Syndromes of bodily distress or functional somatic syndromes - Where are we heading. Lecture on the occasion of receiving the Alison Creed award 2017, Fink, Per. Journal of Psychosomatic Research, Volume 97, 127 - 130 https://www.jpsychores.com/article/S0022-3999(17)30445-2/fulltext Lecture slides: http://www.eapm2017.com/images/site/abstracts/PLENARY_Prof_FINK.pdf

 

[Dx Revision Watch]

Since neither bodily distress disorder nor bodily distress syndrome are included in the DSM-5, and there is no indication it will ever be recognized as a valid diagnosis by the American Psychiatric Association, it poses a somewhat lesser threat to patients in the United States. Its inclusion in ICD-11, however, can particularly impact other countries.

But the DSM-5 has Somatic symptom disorder (SSD) to which ICD-11's BDD is conceptually aligned, and which is already being used in the U.S. and beyond - and which poses a similar threat to patients in those countries that use the DSM as BDD's inclusion in ICD-11 will eventually pose.

 

[Arnie Pye]

@Dx Revision Watch (Sorry, I can't tag you for some reason, so you probably won't see this.)

I have a question about one of the things you have quoted in post #11 :

These proponents renamed it bodily distress disorder and replaced the medically unexplained criteria with the concept of long-standing excessive distress and excessive thoughts, and behaviors towards pain that are considered of either known or unknown etiology

Can you, or anyone else, tell me what is considered to be healthy "behaviours towards pain"? I've obviously been getting it wrong my entire life because getting a doctor to believe I'm in pain has been an impossible task throughout my life.

 

[Arnie Pye]

Great to hear that you feel better!
I also have hypothyroidism and had unusually high anxiety before getting diagnosed.
Optimized nutrition I agree is very valuable to improve one's well being.

I spoke too soon, and I take it all back. I saw a doctor today about something. What a waste of my time that was. As usual I wasn't taken seriously and I would have been been better off staying at home. Aaaargh!

Sorry, off topic...

 

[Dx Revision Watch]

The paper states:

In the transition from somatoform disorder to somatic symptom disorder, the most significant change was the removal of the invalid distinction between medically explained and medically unexplained somatic complaints. A group of proponents in Europe salvaged the diagnostic category with a substitute phrase and were able to have it listed in the proposed ICD-11 (6C20). These proponents renamed it bodily distress disorder and replaced the medically unexplained criteria with the concept of long-standing excessive distress and excessive thoughts, and behaviors towards pain that are considered of either known or unknown etiology [120].

Reference 120 is for the paper:

Budtz-Lilly, A.; Schröder, A.; Rask, M.T.; Fink, P.; Vestergaard, M.; Rosendal, M. Bodily distress syndrome: A new diagnosis for functional disorders in primary care? BMC Fam. Pract. 2015, 16, 180. [Google Scholar] [CrossRef] [PubMed]​

These are collaborators of Per Fink. What they are discussing in this paper was the proposed adaptation of Fink's Bodily distress syndrome (BDS) for use in primary care.


The external sub working group that was assembled by WHO/ICD Revision to develop a replacement for the ICD-10 Somatoform disorders for use in the core ICD-11 was the Somatic Distress and Dissociative Disorders Working Group (S3DWG), chaired by Prof O Gureje.

This ICD-11 sub working group reported directly to the ICD-11 Revision Steering Group.

It wasn't a "A group of proponents in Europe" that "salvaged the diagnostic category with a substitute phrase and were able to have it listed in the proposed ICD-11 (6C20)"

- the ICD-11 S3DWG sub working group were expressly tasked with developing a replacement for most of the ICD-10 F45.x Somatoform disorders categories.

The authors of this paper are confusing collaborators of Fink who were lobbying for a BDS like construct for use in primary care (and in the non mandatory ICD-11 PCH 27 mental disorder guideline) with the WHO assembled S3DWG working group that were tasked to develop a replacement for most of the ICD-10 Somatoform disorders. The S3DWG's recommendation for the core ICD-11 was for the SSD-like construct: 6C20: Bodily distress disorder (which ICD Revision Steering Group, the WHO, and the MSAC and CSAC committees went forward with).

I'm afraid this paper is dreadfully muddled in places.

 

[Sly Saint]

The authors of this paper are confusing collaborators of Fink who were lobbying for a BDS like construct for use in primary care (and in the non mandatory ICD-11 PCH 27 mental disorder guideline) with the WHO assembled S3DWG working group that were tasked to develop a replacement for most of the ICD-10 Somatoform disorders. The S3DWG's recommendation for the core ICD-11 was for the SSD-like construct: 6C20: Bodily distress disorder (which ICD Revision Steering Group, the WHO, and the MSAC and CSAC committees went forward with).

I'm afraid this paper is dreadfully muddled in places.

As with PWs muddling of the two
https://www.s4me.info/threads/a-per...-nosology-2019-white.10635/page-4#post-189049

 

[Dx Revision Watch]

As with PWs muddling of the two
https://www.s4me.info/threads/a-per...-nosology-2019-white.10635/page-4#post-189049

Indeed, and that reminds me that I need to chase Dr Mathew Mercuri, the incoming Editor-in-Chief of JECP, for the status of my request for a correction/corrigenda for the PD White commentary.

The last I heard from Dr Mercuri (by email, August 14, 2019), he had followed up on my suggestion that he approach key WHO/ICD-11 personnel and was waiting on clarifications from the WHO's Dr Robert Jacob and Dr Geoffrey Reed, in support of the textual and screenshot evidence I had already furnished him with that clearly demonstrate PDW is mistaken in his assertions around ICD-10 coding.

I now have quite a collection of papers and presentations by academics, researchers and clinicians evidencing the muddling of the core ICD-11 BDD diagnostic construct with the Fink et al (2010) BDS diagnostic. All of which have been provided to WHO and ICD Revision as examples.

This concern was noted (but not addressed) in the Letter to the Editor below from WHO's Dr Robert Jakob, the WHO's Dr Geoffrey Reed et al:

https://onlinelibrary.wiley.com/doi/full/10.1002/wps.20635

Letter to the Editor

Free Access
Public stakeholders’ comments on ICD‐11 chapters related to mental and sexual health

Johannes Fuss
Kyle Lemay
Dan J. Stein
Peer Briken
Robert Jakob
Geoffrey M. Reed
Cary S. Kogan

First published: 06 May 2019

https://doi.org/10.1002/wps.20635


(...)

A majority of submissions regarding bodily distress disorder were critical, but were often made by the same individuals (N=8). Criticism mainly focused on conceptualization (48%; κ=0.64) and the disorder name (43%; κ=0.91). Use of a diagnostic term that is closely associated with the differently conceptualized bodily distress syndrome5 was seen as problematic. One criticism was that the definition relies too heavily on the subjective clinical decision that patients’ attention directed towards bodily symptoms is “excessive”. A number of comments (17%; κ=0.62) expressed concern that this would lead to patients being classified as mentally disordered and preclude them from receiving appropriate biologically‐oriented care. Some contributors submitted proposals for changes to the definition (30%; κ=0.89). Others opposed inclusion of the disorder altogether (26%; κ=0.88), while no submission (κ=1) expressed support for inclusion. The WHO decided to retain bodily distress disorder as a diagnostic category6 and addressed concerns by requiring in the CDDG the presence of additional features, such as significant functional impairment.

[Extract ends]

 

[Dx Revision Watch]

...The WHO decided to retain bodily distress disorder as a diagnostic category6 and addressed concerns by requiring in the CDDG the presence of additional features, such as significant functional impairment.

I have it on good authority that publication of the ICD-11 Clinical Descriptions and Diagnostic Guidelines for Mental and Behavioural Disorders (CDDG) - which is ICD-11's equivalent publication to the ICD-10 "Blue Book" - is likely to be held back until next year, as some disorders are still undergoing field trials or assessment of completed field studies.

The CDDG provides expanded clinical descriptions, essential (required) features, boundaries with other disorders and normality, differential diagnoses, additional features, culture-related features and codes for all mental and behavioural disorders commonly encountered in clinical psychiatry; it is intended for mental health professionals and for general clinical, educational and service use.

The CDDG does not provide diagnostic criteria. The essential features are less rigid than DSM-5’s criteria sets and allow practitioners more flexibility to use clinical discretion when making a diagnosis.

(I have not seen a recent iteration of the CDDG's draft text for Bodily distress disorder as these drafts are not in the public domain - but I have a copy of the draft text, as it had stood, in 2016.)

 

[Dx Revision Watch]

Medically unexplained symptoms, somatoform disorder, and compensation neurosis are outdated and/or inaccurate terms.

If you haven't come across the term "compensation neurosis" (and I haven't seen the term referenced in any papers I've read since 2010 discussing somatoform disorders, MUS, FSSs etc):

"Compensation neurosis" was an inclusion term in ICD-9 under code 300.1.

In ICD-10, it is listed in the Tabular List as an inclusion under F68.0 Elaboration of physical symptoms for psychological reasons:

https://icd.who.int/browse10/2016/en#/F68.0

F68 Other disorders of adult personality and behaviour

F68.0 Elaboration of physical symptoms for psychological reasons
Physical symptoms compatible with and originally due to a confirmed physical disorder, disease or disability become exaggerated or prolonged due to the psychological state of the patient. The patient is commonly distressed by this pain or disability, and is often preoccupied with worries, which may be justified, of the possibility of prolonged or progressive disability or pain.

Compensation neurosis​

----------------------

It was not apparently included in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) and it's not included in DSM-5 (May 2013).

 

[Pechius]

Merged thread

A bit too opmtimistic, IMO:

A lack of understanding of myalgic encephalomyelitis/chronic fatigue syndrome both prior to and after the Institute of Medicine Report on this disorder has contributed to many patients feeling maligned, blamed, untreated, and undertreated. Some patients stated that they felt belittled, dismissed, and ignored by their health care professionals who followed some of the commonly disseminated guidelines. More than 80% of patients with myalgic encephalomyelitis/chronic fatigue syndrome (CFS) go undiagnosed, while 65% of patients spend more than a year seeking the correct diagnosis [31,32,33,34]. Treatment recommendations based upon a graded activity and a cognitive behavioral therapy (PACE) trial were previously adopted by many healthcare organizations. However, the research was highly flawed and never supported the belief that ignoring symptoms would lead to recovery [35,36]. The inaccurate treatment recommendations based upon the PACE trial recommended patients should ignore symptoms. In addition, patients were given a form of cognitive behavior therapy that challenged their beliefs of their having any physiological illness limiting their ability to exercise. Instead, to become more active—and possibly fully recover—they only needed to ignore their symptoms [37]. Many patients failed to respond to this treatment, and the research supporting the concept that exercise can treat chronic fatigue syndrome was subsequently rejected by Cochrane stating that the work does not meet the organization’s “quality standards.” [38]. After the PACE study was found to be invalid, there have been further advances in the field, and many guidelines have since been revised [39].

https://www.mdpi.com/2227-9032/7/4/114/htm