Talk:Pain/Archive 3

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Clarification on the use of certain pain-related terms

"A first caveat concerning such a distinction is that it uses 'physical pain' in a sense that normally includes not only the 'typical sensory experience' of 'physical pain' but also other unpleasant bodily experience such as itch or nausea." I've never seen the word "pain" used to mean itch or nausia. I'll be removing than in the new year, unless anyone can convince me otherwise.Anthony (talk) 19:43, 24 December 2008 (UTC)

It is not that the word "pain" is used to mean itch or nausea, it is that people make two wide categories, physical and mental pain, and thereafter unpleasant experiences like itch or nausea are said to belong to the "physical pain" category. The sentence could probably be reworded to make it clearer. --Robert Daoust (talk) 12:39, 30 December 2008 (UTC)

The meaning is clear, but I've never encountered an instance of "physical pain" as a category including nausia or itch. It seems to me you are saying "physical pain" is the same as "physical suffering". "Pain" is occasionally a synonym of "suffering" but "physical pain" is not a synonym of "physical suffering". Anthony (talk) 10:45, 4 April 2009 (UTC)

What about rewording thus: "A first caveat concerning such a distinction is that it uses 'physical pain' in a broad sense that includes not only 'physical pain' in the narrow sense but also other unpleasant bodily experiences such as itch or nausea."? It seems to me that pain is more than occasionally a synonym of suffering, that people who make the distinction between physical and mental pain in the broad sense include, then, phenomena like nausea and itch under the category 'physical pain' (in the broad sense), and that it should be easy to find example of this in the literature. Besides, I understand that 'physical pain in the narrow sense' and 'physical suffering' are not synonyms, but I have seen them used as such in some circumstances. Anyway, please let us know whether you find the proposed rewording acceptable. --Robert Daoust (talk) 16:44, 6 April 2009 (UTC)

Vitamin D, Mayo Clinic, and pain

I find it troubling that reasonable, uncontroversial statement [1] sourced from a press release from AAAS (the publisher of Science) on a release from the Mayo Clinic (a highly respected research organization) would be removed on what is basically a technicality of MEDRS. The Eurekalert release was a copy of the Mayo Clinic release. I figured since it is the AAAS, it's not going to be egregiously misinterpreting studies. I'll admit that I miscited the study (it wasn't the Mayo Clinic, it was their researchers), but that could have been fixed rather than deleted. At the least I would have expected the content to be replaced by something better than deleted.

Additionally, going to a 2004 review just because it's in PubMed, and ignoring a free comprehensive report authored by an expert in pain and reviewed by 8 scientists, does a disservice to the readers, who largely aren't able to pull up the Nutrition Review. II | (t - c) 00:24, 26 March 2009 (UTC)

Incidentally, there is a PubMed-indexed review of 6 case series [2]. However, it's so trivial in comparison to Leavitt's comprehensive review (which reviews over three thousand cases and also overdoses) that I'm reluctant to include it. II | (t - c) 00:58, 26 March 2009 (UTC)

I can't read it at home so I don't know what it says, but PMID 19084336 is a 2008 review of Vitamin D and chronic pain that meets MEDRS and references the Mayo Clinic study you mentioned. Looie496 (talk) 01:05, 26 March 2009 (UTC)

Having read that study, it offers major benefits over Leavitt's document, and actually shows that Leavitt's document appears to be biased since it strangely excludes all the dbRCTs. Although they were small, all but one (the smallest) had no stat. significant effect. These RCTs largely used calcifediol (including the positive study; one used nandrolone deconoate, another used ergochalciferol which may not be as potent) while the non-dbRCTs largely used the cholecalciferol. Maybe it doesn't matter but it seems interesting. They also used generally lower doses than the case-series. II | (t - c) 03:06, 26 March 2009 (UTC)

ImperfectlyInformed knows fully well that there is a guideline that favours peer-reviewed secondary sources over the kind of sources that he has insisted on adding. This is not the first time we have clashed over this. I find it silly that we should discard a higher-quality source just because not everyone can access it freely. By that logic, we should supply crappy sources just because thy are accessible and deny the reader the kind of verifiability that we are all meant to be striving for. I think Looie496's source is another excellent example of a recent scientific review of vitamin D and chronic pain. JFW | T@lk 02:04, 26 March 2009 (UTC)

Obviously, my argument is that Leavitt's document meets MEDRS, as it is peer-reviewed (8 reviewers) and published on Pain Treatment Topics, an organization affiliated with several major pain organizations. There are major advantages to sourcing to freely-available publications, not least that they reduce selectively-cited POV and OR. Hitting me with a straw man that "all sources should be crappy" doesn't really help things. I'm fine with for-pay sources provided that a convincing argument for their higher-quality is presented and the presenter indicates that they did more read the title and abstract after picking the first review they could find on PubMed. I made a point: there are 8 "medical reviewers" listed on Leavitt's document; the first two are acknowledged experts on vitamin D, and in fact one of them, Holick, published a 2008 review in Nutrition Reviews (PMID 18844847) and a 2007 review in the NEJM. Leavitt's article got more review, and from people with greater expertise, than the average journal article is likely to get – admittedly, even after that it appears biased (see comment above). I don't see how your 2004 article in Nutrition Reviews provides any benefits over Leavitt's document. II | (t - c) 03:06, 26 March 2009 (UTC)

Thank you for finding a suitable published peer-reviewed source that seems to contain more useful content. Perhaps I'm oldfashioned, but I will prefer a proper indexed normal journal over a website, even if the reviewers are stellar. JFW | T@lk 22:45, 26 March 2009 (UTC)

Thank you for the gentler tone. The credit goes Looie496 for finding it. I prefer articles which anyone can see and agree are cited properly whenever possible, and it's nice to know who the reviewers are as well. With the exception of the BMC journals, peer review seems like a bit of a black box. And PubMed-indexed does not equal quality. II | (t - c) 22:53, 27 March 2009 (UTC)

I think observations on the peer review process are well outside WP:TALK and might be more useful on WT:MEDRS. Or perhaps not. JFW | T@lk 19:59, 28 March 2009 (UTC)

Can I just insert my very deep misgivings concerning the inclusion of a discussion about the merits of specific surgical, drug, nutritional, alternative or CBT therapies in this article (which should, I believe, be about the nature of pain, per se). The essentials of the above discussion appear on the Vitamin D page. I've added a link to that page under "Alternative Therapies" at bottom of the Chronic pain page. Anthony (talk) 13:06, 10 April 2009 (UTC)

In their review of the literature at January 2009, Straube et al (ref #25 in the article) in the prestigious journal Pain conclude: The presently available evidence does not allow us to conclude that vitamin D is relevant to chronic pain. Anthony (talk) 15:38, 17 August 2009 (UTC)

Pain in fish and lobsters

Commenting on this newly added material: I think it belongs, but the section on lobsters is far too long given the breadth of this article's domain. It should be reduced to a paragraph, and probably placed in the same section as the fish material, in my opinion. Looie496 (talk) 15:25, 3 May 2009 (UTC)

i'm having a lot of pain in my lower part of my back.when i get up in the morning. it take most of the day for it to easy off. but still hurts —Preceding unsigned comment added by 66.26.95.44 (talk) 14:56, 15 June 2009 (UTC)

Introduction

I have changed the first sentence for clarity and brevity. Since all the definitions of sensation I could find included perception, awareness or sensorium, I don't think we need to bother about that meaning, peculiar to psychology, that says sensation is the effect of a stimulus on a sensory receptor. The general reader knows what sensation means in this context.

Definitions of sensation:

• An impression produced by impulses conveyed by an afferent nerve to the sensorium. Dorland's Illustrated Medical Dictionary
• In medicine and physiology, sensation refers to the registration of an incoming (afferent) nerve impulse in that part of the brain called the sensorium, which is capable of such perception. Therefore, the awareness of a stimulus as a result of its perception by sensory receptors. MedTerms.com Medical Dictionary
• An impression, or the consciousness of an impression, made upon the central nervous organ, through the medium of a sensory or afferent nerve or one of the organs of sense; a feeling, or state of consciousness, whether agreeable or disagreeable, produced either by an external object (stimulus), or by some change in the internal state of the body. ("Perception is only a special kind of knowledge, and sensation a special kind of feeling. . . . Knowledge and feeling, perception and sensation, though always coexistent, are always in the inverse ratio of each other." Sir W. Hamilton) Mondofacto.com
• An impression produced by impulses conveyed by an afferent nerve to the sensorium. medical-dictionary.thefreedictionary.com
• A physical feeling or perception resulting from something that happens to or comes into contact with the body. Compact Oxford English Dictionary
• A perception associated with stimulation of a sense organ or with a specific body condition (the sensation of heat; a visual sensation). American Heritage Dictionary of the English Language
• Physical feeling: a physical feeling caused by having one or more of the sense organs stimulated (a burning sensation in my mouth and throat) Encarta® World English Dictionary, North American Edition
• a : a mental process (as seeing, hearing, or smelling) resulting from the immediate external stimulation of a sense organ often as distinguished from a conscious awareness of the sensory process — compare perception
  b : awareness (as of heat or pain) due to stimulation of a sense organ
  c : a state of consciousness due to internal bodily changes (a sensation of hunger) Merriam-Webster's Online Dictionary, 11th Edition
• The ability to feel something physically, especially by touching, or a physical feeling that results from this ability (a burning sensation, I had no sensation of pain whatsoever, The disease causes a loss of sensation in the fingers.) Cambridge International Dictionary of English
• A physical feeling or perception from something that comes into contact with the body; something sensed Wiktionary
• An immediate reaction to external stimulation of a sense organ; conscious feeling or sense impression' (a sensation of cold) Webster's New World College Dictionary, 4th Ed.
  Anthony (talk) 17:05, 17 August 2009 (UTC)

The Dimensions of Pain

I'm thinking of adding a section like this. Comments?
In 1968 Melzack and Casey described pain in terms of its three “dimensions”:

  1. Sensory-discriminitive (location, intensity, quality, duration)
  2. Motivational-affective (unpleasantness and urge to escape the unpleasantness)
  3. Cognitive-evaluative

They asserted that pain's unpleasantness varies independently of its intensity, and “higher” cognitive activities such as appraisal, cultural values, distraction and hypnotic suggestion can influence both unpleasantness and intensity. "Pain varies along both sensory-discriminative and motivational-affective dimensions. The magnitude or intensity along these dimensions, moreover, is influenced by cognitive activities such as evaluation of the seriousness of the injury." (p. 434) They conclude with a call for science to start taking seriously this "top down" effect of cognition on pain. The chapter was seminal, and over the last forty years the effect of thinking and motivation on the intensity and unpleasantness of pain has been closely studied and an enormous effort has been put into devising cognitive and behavioural techniques for the amelioration of pain [Vlaeyen & Morley, 2005].

• Melzack, R. & Casey, K.L. (1968.) Sensory, motivational and central control determinants of chronic pain: A new conceptual model. In: The Skin Senses, edited by D.L.Kenshalo, pp. 423 – 443. Springfield, Illinois. Thomas.
  
• Vlaeyen, J.W.S. & Morley, S. (2005) Cognitive-Behavioral Treatments for Chronic Pain: What Works for Whom? Clinical Journal of Pain. Special Topic Series: Cognitive Behavioral Treatment for Chronic Pain 21(1) 1-8

Anthony (talk) 18:23, 17 August 2009 (UTC)

And maybe this:

Bonjour Anthony. I am happy to see that work is being done on Pain. I cannot be involved now, but am following with great interest. I see that you wrote to Bud Craig. He is wonderful, but I am afraid his conception of consciousness is limited to self-consciousness. As far as I can understand, only animals who succeed in the mirror test are sentient, according to his theory that a functional insula is indispensable for producing a sentient mind that can feel. On another subject, congrats for starting the Dimensions section. We will have to explain somewhat or describe what are the three dimensions. Including Rainville's work in the section is a good idea, and it can be linked ideed to the conceptual model of Melzack and Casey, but I am wondering if the following sentences can be said:

"They theorized that pain's unpleasantness varies independently of its intensity"

"cognitive activities (...) can influence both unpleasantness and intensity"

"over the last forty years the effect of thinking on the intensity and unpleasantness of pain has been closely studied"

"In 1997 Rainville and colleagues[21] tested Melzack and Casey's 1968 model"

Happy trail! --Robert Daoust (talk) 17:23, 9 September 2009 (UTC)

Hi Robert. Regarding your above points:

• I see that you wrote to Bud Craig. He is wonderful, but I am afraid his conception of consciousness is limited to self-consciousness. As far as I can understand, only animals who succeed in the mirror test are sentient, according to his theory that a functional insula is indispensable for producing a sentient mind that can feel.
  

I've copied this down to "Pain in Other Species" below and will respond when I've had a chance to think about it.

• We will have to explain somewhat or describe what are the three dimensions.
  

How about fleshing it out along these lines:

In 1968 Melzack and Casey described pain in terms of its three “dimensions”:

• Sensory-discriminitive (the subject's experience of the location, intensity, quality and duration of the pain)
• Motivational-affective (negative affect and urge to escape negative affect)
• Cognitive-evaluative

They theorized that the degree of distress a subject feels (the affective-motivational dimension) varies independently of the intensity of the pain (the sensory discriminative dimension), and that “higher” cognitive activities such as appraisal, cultural values, distraction and hypnotic suggestion (the cognitive-evaluative dimension) can influence both unpleasantness and intensity.

"Pain varies along both sensory-discriminative and motivational-affective dimensions. The magnitude or intensity along these dimensions, moreover, is influenced by cognitive activities such as evaluation of the seriousness of the injury." (p. 434)

They conclude with a call for science to start taking seriously this "top down" effect of cognition on pain. The chapter was seminal, and over the last forty years the effect of thinking on the intensity and unpleasantness of pain has been closely studied and an enormous effort has been put into devising cognitive and behavioural techniques for the amelioration of pain.

In 1997 Rainville and colleagues tested Melzack and Casey's 1968 model using PET to monitor brain activity while their subjects' left hands were immersed in painfully hot water. Using hypnotic suggestion (the cognitive-evaluative dimension), they were able to vary the degree of distress experienced by their subjects (the affective-motivational dimension), while keeping their subjects' perception of the pain intensity (the sensory-discriminitive dimension) constant.

• I am wondering if the following sentences can be said:

"They theorized that pain's unpleasantness varies independently of its intensity"
Yes. That was the point of designating them two distinct dimensions - this word "dimension", the way they and psychiatric theorists use it, means a quality that can vary in degree or intensity.

"cognitive activities (...) can influence both unpleasantness and intensity"
That is my reading of the quote from page 434.

"over the last forty years the effect of thinking on the intensity and unpleasantness of pain has been closely studied"
It's all relative, I suppose. The ratio of the number of published peer-reviewed papers dealing with the effect of cognition on pain to those dealing with pain on cognition is 95:5.

"In 1997 Rainville and colleagues[21] tested Melzack and Casey's 1968 model"
Would "In 1997 Rainville and colleagues[21] supported Melzack and Casey's 1968 model" be better? Anthony (talk) 20:09, 9 September 2009 (UTC)

I am sorry to say it so late, but the problem, IMHO, is that the 1968 model and the 1997 study are wide apart in time. Using the semantics (the words unpleasantness, intensity) of the second to speak of the first sounds like an anachronism (and somewhat like 'original research')... I was suggesting to describe on its own the classic 'historical' model, and to add at the end of the section the relatively recent findings of Rainville et al. But I am perhaps indulging in too much perfectionism... --Robert Daoust (talk) 23:37, 9 September 2009 (UTC)

G'day Robert! Rainville and colleagues begin their paper with:

"Affective aspects of pain, such as perceived

unpleasantness, have been classically considered

to be distinct from the simple sensory

dimensions of pain, which include the

perception of location, quality, and intensity

of noxious stimulation (Melzack & Casey, 1968)."

Their paper is about supporting this "classic" perspective, offering more direct evidence than had, until then, been available, i.e., PET. Melzack and Casey begin their chapter with:

"The problem of pain, since the beginning of

the century, has been dominated by the concept

that pain is a sensory experience. Yet pain

has a unique, distinctly unpleasant, affective

quality that differentiates it from sensory

experiences such as sight, hearing, or touch...

Even the concept of pain as a perception,

with full recognition of past experience, attention

and other cognitive determinants of sensory

quality and intensity, still neglects the crucial

motivational dimension"

The terms you are concerned about and their usage are common to both papers. Anthony (talk) 13:13, 10 September 2009 (UTC)

But I do agree, the stuff on Rainville et al. is far too bulky. I'll shrink it down to a sentence or two. And the "dimensions" stuff still needs more flesh and improved readability. I'll work on that now. Anthony (talk) 13:41, 10 September 2009 (UTC)

Pain and the Brain

In 1997 Rainville and colleagues tested Melzack and Casey's 1968 model using PET to monitor brain activity while their subjects' left hands were immersed in painfully hot water. Using hypnotic suggestion, they were able to vary the unpleasantness experienced by their subjects, while keeping both the stimulus intensity and their subjects' perception of the pain intensity constant. They found that this variation in perceived unpleasantness was mirrored by variation in activity in the anterior cingulate cortex (ACC) and concluded that, though many parts of the brain exhibit heightened activity during pain, and these regions are highly interactive, nevertheless "there appears to be at least a partial segregation of function between pain affect and sensation, with ACC activity possibly reflecting the emotional experience that provokes our reactions to pain".

This seminal paper provided neuroimaging support for Melzack and Casey's distinction between the motivational-affective and sensory-discriminative dimensions of pain, showed that higher cognition can modulate unpleasantness independent of the sensory-discriminitive dimension, and shed a little more light on the role played by several brain regions in the experience of pain.

Neuroimaging support for the involvement of the anterior cingulate cortex in pain's unpleasantness was not entirely unexpected. It had been known for decades that surgical removal of the anterior cingulate relieves the distress of pain without affecting its intensity, and this surgical intervention is used even today in cases of extreme and otherwise incurable chronic pain.

• Rainville, P. (2002) Brain mechanisms of pain affect and pain modulation. Current Opinion in Neurobiology, 12(2),195-204.

• Rainville, P., Duncan, G.H, Price, D.D., Carrier, B. & Bushnell, C. (1997) Pain affect encoded in human anterior cingulate but not somatosensory cortex. Science 277 (5328) 968-971.

• Foltz, E.L. & White, L.E. (1962) Pain “relief” by frontal cingulotomy, Journal of Neurosurgery, 19, 89-100.

Anthony (talk) 20:41, 17 August 2009 (UTC)

I'm strongly in favor of adding material distinguishing dimensions of pain. Wikipedia policy for medical-related articles (WP:MEDRS) generally prefers citing review papers rather than primary research papers, and there are quite a number of papers in the literature relating to the role of the ACC in "suffering" as opposed to the physical qualities of pain, so the specific articles you've mentioned might not be the best to use. Regards, Looie496 (talk) 21:03, 17 August 2009 (UTC)

G'day. Pleased to hear it, Looie496, and thank you for your advice. The best review of the neural correlates of the dimensions of pain that I could find happens to have been written by Rainville (referenced above). Any thoughts? Should I post these? Anthony (talk) 15:56, 31 August 2009 (UTC)

The quality of this article suffers from a lack of dedicated editors

The article Pain occupies approximately the 8500th rank in traffic on Wikipedia (on 3 millions articles). It is viewed some 2,000 times per day. I find it strange that such a top-importance article is still rated only b-class on the quality scale. The problem, obviously, is a lack of dedicated editors. Why is there a lack of editors?

As for me, I am willing to contribute, but only within a dynamic cooperative framework. Much remains to do in this article. I have suggested previously things to include in the “to-do list” (see Talk:Pain/Archive_2#Introducing_to-do_list and Talk:Pain/Archive_2#Major_editing_of_the_article, and see also, by others, Talk:Pain/Archive_2#Suggestions_for_med_collaboration_of_the_week). To begin with, parts of this discussion page should be placed into archives. As to recent edits, I think the section “In other species” should be given another name and should be made shorter, crisper. The new lead paragraph in the article introduction is better than the old one, but there is a problem with the word ‘sensation’: there should be a footnote explaining its use, or perhaps it could be replaced by ‘feeling’.

It seems to me that one fundamental reason why there is a lack of editors for Pain is that the subject is difficult. It is difficult emotionally, of course, but also intellectually, be it only because there is still so much confusion in psychology on what is emotion, feeling, the affective, consciousness, mind. All those notions are involved in the basic nature of pain. How could an encyclopedia, which is not a place for original research, clarify what is still fraught with confusion in the most enlightened parts of our culture? Nonetheless, I believe that if we were a few who would care, we could bring the article Pain to the highest level of quality, and thus do a favour for countless readers and for humanity as a whole. --Robert Daoust (talk) 15:11, 27 August 2009 (UTC)

My response is basically, go for it. I'm a neuroscientist but don't know enough about pain per se to make major original contributions to this article; however I'll be happy to be part of a "dynamic cooperative framework". I think the main reason there are so many important articles like this needing work is that there are relatively few editors who know enough to work on them. So if you do, go for it. Looie496 (talk) 18:03, 27 August 2009 (UTC)

Looie, I went for it a lot already, with 52 edits on Pain beween December 2006 and April 2009. My problem is that because I have met no other editor who makes "major original contributions" to Pain (and/or Suffering), I feel like working alone, and I am at Wikipedia precisely for working with others. I find interesting your hypothesis that there is relatively few editors who know enough to work on important articles like this. If this is the case, a proposal at http://strategy.wikimedia.org/wiki/Call_for_proposals might be to identify the most needy articles among the 10,000 most visited ones, and focus a participation effort on them. For instance, I believe that among the more than 7,000 members of the International Association for the Study of Pain, it should be possible to find at least some who would care about this article. --Robert Daoust (talk) 22:34, 27 August 2009 (UTC)

Well, I put a lot of effort into brain mostly on my own, although many others chipped in after I submitted it to FA, so I completely understand how discouraging the lack of feedback can be. We at WikiProject Neuroscience are doing all we can to encourage more experts to contribute, and maybe even making some progress, but there's still a great deficiency of expertise. All I can say is that if you get it to the level where it can be submitted for GA review, or even eventually FA, you'll get a lot more feedback, though still mostly from non-experts. Right now we are the pioneers, it's our lonely work that will encourage other less bold folks to move into the territory. (And if you want to work on a pain-related article that gets lots of attention, there is always fibromyalgia.) Regards, Looie496 (talk) 22:45, 27 August 2009 (UTC)

I look in from time to time and have seen your firm but sensitive hand guiding this page towards perfection for years, Robert. It has been marvelous to watch. Your point about the aversiveness of the topic is so on the money. I actually think it is up to patients to push this profoundly important scientific backwater into its place in the sun. Re your above comments:

• "parts of this discussion page should be placed into archives." I agree but don't know how to do it. Do you?
• "I think the section In other species should be given another name and should be made shorter, crisper." I agree.
• "The new lead paragraph in the article introduction is better than the old one, but there is a problem with the word sensation: there should be a footnote explaining its use, or perhaps it could be replaced by feeling". I agree it is not yet right. What about

  Pain, in the sense of physical pain, is the feeling typically associated with bodily harm. Pain usually consists of unpleasantness, motivation to withdraw or protect, and awareness of the quality, location, intensity and duration of the pain, though it is possible to experience pain without one or more of these elements. Pain is often accompanied by emotions (e.g., fear, anxiety, rage) and may always be accompanied by cognitive impairment (e.g., attention and working memory deficits).

  How's that for going for it? Also, is Rainville's 2002 review, above, adequate support for my proposed new sections on the dimensions of pain and its neural correlates? Anthony (talk) 15:54, 31 August 2009 (UTC)

In the absence of any direct way of measuring it, defining pain is very tricky. "Bodily harm" is not quite precise enough, because that can also be indicated by feelings of sickness, dizziness, thirst, suffocation, weakness, etc, which may not be painful at all. We learn what the word "pain" means by watching how other people use it -- we see that they use it mainly for mechanical damage -- we notice that when our own bodies are mechanically damaged we usually feel specific types of sensations, and we learn to apply the word "pain" to those sensations. I'm afraid this is all too complicated for the lead, but maybe replacing "bodily harm" with "mechanical damage such as a cut or a bruise" would work. Also I don't think that pain is necessarily accompanied by cognitive deficits -- sometimes people who feel very sleepy will do something painful just to wake themselves up. It's sort of a U-shaped curve thing. Looie496 (talk) 16:39, 31 August 2009 (UTC)

That was quick. Thank you Looie496. I agree. In light of what you say above, the only solution I can think of is to offer a couple of examples. How about this?

Pain, in the sense of physical pain, is the unpleasant feeling you associate with stubbing a toe or burning a finger. It usually consists of unpleasantness, motivation to withdraw or protect, and awareness of the quality, location, intensity and duration of the pain, though it is possible to experience pain without one or more of these elements. Pain is often accompanied by emotions (e.g., fear, anxiety, rage) and cognitive impairment (e.g., attention and working memory deficits).

I can support the cognitive effects of acute and chronic pain but they may not always be present (though I'm pretty confident they are). Cheers Anthony (talk) 17:17, 31 August 2009 (UTC)

Yes, that works better for me, perhaps with a bit of copy-editing but that can come later. Regards, Looie496 (talk) 17:39, 31 August 2009 (UTC)

You are being overly kind to me, Anthony, but thanks for your support and your well informed contributions. Yes, patients might do a lot for the advancement of pain knowledge and management. After all, John Bonica, founder of the International Association for the Study of Pain, was himself a chronic pain sufferer. As to the intro and to Dimensions of pain, let's be bold... Defects, if there are, might always be corrected later. --Robert Daoust (talk) 16:00, 1 September 2009 (UTC)

Hi Robert. Credit where it's due.

Hi Looie496. Re your editing of the intro':

• I understand that saying pain is the feeling common to both stubbing a toe and burning a finger is a bolder claim than saying it is a feeling common to both but I believe the definite article applies. I think the mistake I made here was choosing two examples that were peripheral and involving tissue damage or potential for it. May I suggest:

Physical pain is the unpleasant sensation common to such experiences as a headache and a stubbed toe.

• Robert suggested feeling rather than sensation and I agree with him, largely because of the fact that sensation implies some kind of sensory input. not present in, for instance, my headaches (can't speak for anyone else). Headache, for me, is not like noise that's too loud or excessive heat; it's not a sensation crossing its pain threshold. For me, headache is elemental pain. I understand language is inadequate here, and all we seem to have to choose from is feeling and sensation. In the case of pain I think feeling is more accurate. Feeling includes not just sensations, but emotions. Pain, I believe, is closer to an emotion than a sensation. It can be triggered by too much of a sensation. Bud Craig (who is unravelling the role of the insula in pain) calls pain a "homeostatic emotion".
• I think that including headache as an example obviates the need for "but sometimes appearing without any overt bodily damage". Anthony (talk) 16:49, 1 September 2009 (UTC)

Points taken. To me the word "feeling" is pretty nebulous, that's why I changed it. It isn't 100% clear to me that pain is the only feeling that a stubbed toe and a headache have in common -- how about annoyance, for example? But I don't have very strong opinions about any of this. Looie496 (talk) 16:59, 1 September 2009 (UTC)

Yeah. But we're getting closer! Anthony (talk) 17:01, 1 September 2009 (UTC)

Defining Pain

Defining pain is a challenge. The official definition of the International Association for the Study of Pain is inadequate. Firstly, tissue can be damaged without pain, and physical pain can occur in the absence of damage or even potential damage. Associating it with tissue damage or potential tissue damage is not only tortuous language but also imprecise. So, here we have opted for a couple of cardinal examples of painful situation that nearly everyone has some experience of (headache and a stubbed toe). Secondly, pain is not a sensory experience.

• Sensory means "of the senses" and
• the senses means "the faculty through which the external world is apprehended".

Pain tells us about the state of the body, not the external world. Pain is an emotion; a homeostatic emotion. According to Bud Craig there are two classes of emotion. Classical emotions include lust, anger and fear, and they are feeling responses to environmental stimuli, which modulate our behaviour. Homeostatic emotions are feeling responses to internal states, which modulate our behaviour. Thirst, hunger, salt hunger, air hunger, feeling hot or cold (core temperature), and feeling sleep deprived are all examples of homeostatic emotion; each is an alarm from a body system saying "Things aren't right down here. Go and drink something/eat something/lick salty rocks, breathe, get into the shade/put on something warm/sleep." We begin to feel a homeostatic emotion when one of these systems drifts out of balance, and the feeling prompts us to do what's necessary to restore that system to balance. Pain is a homeostatic emotion telling us "Things aren't right here. Withdraw and protect." Anthony (talk) 18:01, 3 September 2009 (UTC)

You're surely right that "tissue can be damaged without pain, and physical pain can occur in the absence of damage or even potential damage". But people are not born knowing what the word "pain" means, they have to learn it. The only real clues they get are from seeing the situations in which other people use the word. Situations where the causes of pain are invisible are not informative -- if you don't know what pain means, hearing somebody say "I have pain in my head" doesn't tell you anything useful. The situations that teach us what pain means are ones where somebody hurts themself and then says "I have pain". So although the connection between pain and injury is ultimately indirect, injury is still the "doorway to pain knowledge", so to speak. This connection is hard to explain but important to understand. Looie496 (talk) 23:21, 3 September 2009 (UTC)

Hard but crucially importand. You're right Looie, we learn the meaning of pain first by grazing a knee, stubbing a toe, etc. and being told "that's hurt, that feeling is pain." When we feel that feeling in a less public way, such as a headache, toothache or stomach ache, we recognise it and know what to call it. My problem with the IASP definition is twofold. First, they conflate sensory with emotional, and this is by far its biggest problem, in my opinion, and I'd like to discuss it here. Your thoughts on that in relation to Craig's (2003) pain as a homeostatic emotion would be very welcome. My second problem with the definition is this:

In the first part they talk of a feeling associated with actual or potential tissue damage. But to include pain that is not associated with either, they turn to language and say pain also applies to feelings described in terms of such damage. I think this was overreaching.

Harold Merskey (Should be Ronald Melzack) had collected and sorted a large number of pain descriptors into classes, which he then worked into the McGill Pain Questionnaire, in an attempt to help with diagnosis. There were terms related to intensity and distribution over time (e.g., "throbbing", "spreading"), emotional response ("annoying", "terrifying") and other homeostatic emotions ("nauseating", "tiring"), and the rest were all damage related ("rasping", "lacerating", "burning", "stabbing", "crushing", etc.). He headed the IASP task force commissioned to devise a practical definition of pain and it doesn't surprise me at all that "described in terms of such damage" finished off the definition. And it was a valiant effort.

My problem is there are pains that are not associated with tissue damage or its potential and where terms related to tissue damage do not apply. Hence, a headache that is not associated with tissue damage or potential tissue damage, and is not described in terms of such damage, is not embraced by the definition - but assuredly is pain. Some central pain syndromes would also not be covered by it. But this is a minor point. Anthony (talk) 14:42, 5 September 2009 (UTC)

Archiving

I created an archive for 2008 and moved all the material from that year into it. If another extensive discussion develops here, I can set up automated archiving via MiszaBot. Looie496 (talk) 17:01, 31 August 2009 (UTC)

Thank you Looie. I brought back a section with a 2009 entry: it could be useful for the renaming of the article section "In other species". --Robert Daoust (talk) 15:00, 1 September 2009 (UTC)

Pain and animals

This article is getting rather long. Unless there are objections, I propose forking the section on other species to a new article called "Pain and animals". --Geronimo20 (talk) 00:05, 4 September 2009 (UTC)

I second that. Anthony (talk) 12:44, 5 September 2009 (UTC)

I don't think the whole section should go away, but it would make sense to fork the sections on "Pain in fish" and "Pain in crustaceans" to a new subarticle. Looie496 (talk) 16:15, 6 September 2009 (UTC)

So, a brief paragraph about pain in other animals and then a link to a seperate detailed article? Anthony (talk) 09:41, 7 September 2009 (UTC)

Quaternary Ammonium dispute

Let's have some discussion please. Yesterday KKirbyMD (talk · contribs), a new editor, added a paragraph saying:

This theory accounts for the ability of counter-irritant substances applied to the skin to mask underlying high level pain with sensations either hot or cold. These substances include Methyl Salicylate(Wintergreen oil), Menthol, Camphor, Capsaicin (Oil of Capsicum)and Ammonia Solutions including quaternary ammoniums which seem to be particularly effective for pain associated with insect and sea animal venoms that cause stinging pain. Lidocaine, procaine and Tetracaine can be effective but must be infused under the skin in a sufficient quantity to overwhelm receptors. While its effect may be better understood by the theory of nociceptive pain than the gate theory, topically applied Quaternary Ammonium has been demonstrated to effect reduction of chronic orthopedic pain along with other symptoms of inflammation accompanying arthritis. (refs omitted)

This material was then deleted by Jfdwolff (talk · contribs) with an edit summary of no; the deletion was then reverted by Lova Falk (talk · contribs). Could somebody please explain what's going on here? It seems clear to me that the material was out of place where inserted, and I'm not sure it belongs in the article anywhere -- but the clearest thing is that per BRD Lova should not have un-deleted without starting a discussion. Looie496 (talk) 16:12, 6 September 2009 (UTC)

O.K. My opinion is, like the vitamin D stuff above, this information belongs somewhere else. We don't have room here for a detailed presentation of the many proven or promising interventions for pain. Perhaps pain management? Anthony (talk) 10:32, 7 September 2009 (UTC)

The first sentence of the added material might be suitable for the "gate-control" section, except that the term "counter-irritant" is a bit obscure. Looie496 (talk) 16:01, 7 September 2009 (UTC)

Mmmm. But the gate control theory accounts for an enormous number of phenomena. It is quite interesting, actually. I just think it belongs elsewhere. Maybe Gate control theory, Pain management and Quaternary ammonium cation. Anthony (talk) 17:19, 7 September 2009 (UTC)

Okay. To avoid any semblance of edit-warring let's leave that passage in place for another day in case anybody else wants to chime in, and then if there are no developments, you or I can remove it again. Looie496 (talk) 17:55, 7 September 2009 (UTC)

I'm happy to leave it for a week or 2. Often people (like me) only check their edits now and then. OR we could delete it now with a note to "refer to the discussion page". Same applies to pain in other species. I'm OK with either course. But, ultimately, I'd like to get this article down to clear, concise, relevant essentials. Anthony (talk) 18:19, 7 September 2009 (UTC)

Pain in other species

I notice Geronimo20 has forked the text in In other species onto a new article entitled Pain in fish and crustaceans. Nice work Geronimo. I've just forked the text relevant to other animals in general (with a link to Geronimo's page) onto a new page called Pain in animals. Anthony (talk) 19:49, 7 September 2009 (UTC)

Any thoughts on how the remaining section should look? I think this question of whether animals feel pain is fascinating, important and deserves to be well treated here. I've emailed Bud Craig because he's doing the neuroanatomy and knows what's known about the cytology - that is, he's mapping the interface between an emotional response and an awareness of emotional response. And a major thrust of the debate over whether they feel pain turns on the nature of feeling and awareness (consciousness).

I've copied my email to Bud Craig below. It was Robert's suggestion we draw the attention of experts to the deep importance of this page in the evolution of our understanding of pain. 2,000 hits a day. Not only do they have a moral responsibility to be seeing that this article is right, I believe when they see the opportunity these pages present, serious scientists will be falling over themselves.

Date: Mon 7 Sep 19:22:54 WST 2009

From: <ahcole

Subject: Pain as a homeostatic emotion

To: bcraig

Hello Professor Craig

I have recently created a short Wikipedia article entitled "Homeostatic emotion". I have also inserted a section on homeostatic emotion in the Wikipedia Emotion article. This is all preparatory to folding the idea into the Wikipedia article on pain.

I understand this is a different realm from that of peer reviewed journals but the Pain page gets 2,000 hits a day, it is top of the Google search for "pain", and we editors think it really matters that the article throws as much clear light on pain as possible.

Anybody can contribute anonymously to any Wikipedia article. I was wondering if you might consider glancing at the Homeostatic Emotion page and, if I'm misrepresenting you in any way, correct it, before I wrap it into our definition of pain. (Particularly, the distinction I have made between classical and homeostatic emotions.)

You can read the thinking behind our definition of pain if you click the "discussion" tab at the top of the "Pain" article.

By the way, I think you have paved the way for a new age in understanding and treating functional mental illness.

Regards

Anthony Cole.

http://en.wikipedia.org/wiki/Pain

http://en.wikipedia.org/wiki/Homeostatic_emotion

http://en.wikipedia.org/wiki/Emotion#Homeostatic_Emotion

Okay. It's a fan letter too. Anthony (talk) 11:35, 9 September 2009 (UTC)

I see Geronimo has trimmed the Pain and animals section. Nice job. Pain in fish and crustaceans is very neat, too. Anthony (talk) 13:04, 9 September 2009 (UTC)

Geronimo20, I can't make out the meaning of the second sentence in the pain in animals or (the same sentence) in In Other Species here. Do you remember what the original meaning was? Anthony (talk) 16:48, 9 September 2009 (UTC)

I've added a couple of introductory sentences to try to clarify the problem for readers, and also, I think, fixed that sentence, which was probably munged by incomplete removal of material. Feel free to fix anything I got wrong. Looie496 (talk) 17:12, 9 September 2009 (UTC)

Nice! Anthony (talk) 20:33, 9 September 2009 (UTC)

Hi Robert. Quoting Robert Daoust from Dimensions of Pain, above:

"Bonjour Anthony. I am happy to see that work is being done on Pain. I cannot be involved now, but am following with great interest. I see that you wrote to Bud Craig. He is wonderful, but I am afraid his conception of consciousness is limited to self-consciousness. As far as I can understand, only animals who succeed in the mirror test are sentient, according to his theory that a functional insula is indispensable for producing a sentient mind that can feel."

I answered your other questions above (in turquoise). I'll do a bit more reading and get back to you on this one. Anthony (talk) 20:09, 9 September 2009 (UTC)

I have edited Dimensions of Pain per the above discussion with Robert.

Introduction again

I have removed a phrase from the intro for clarity. Can I move the 3rd paragraph of the intro' into the body of the article under its own heading Pain in Medicine? Cheers Anthony (talk) 16:05, 10 September 2009 (UTC) More tinkering. I replaced "rage" with "anger, irritability" to match the acute/chronic character of "fear, anxiety". Qualified "quality" with examples. Added "other bodily feelings" with examples. Anthony (talk) 17:34, 10 September 2009 (UTC)

Big Changes

I have

• moved the 3rd paragraph of the intro' to under Pain in Health Care
• added a section on the evolution of the scientific theory, and
• removed quaternary ammonium info' per above discussion.
  Anthony (talk) 13:32, 13 September 2009 (UTC)

Great work you have been doing lately on the article, Anthony. My turn to be impressed! --Robert Daoust (talk) 14:19, 13 September 2009 (UTC)

Thank you Robert. 122.105.66.107 (talk) 22:52, 16 September 2009 (UTC)

Clarification on the Use of Certain Pain-related Terms

I have

• changed the title of this section to "Terminology" for concision
• removed subsection on "Nociception" because it is covered below under "Mechanism" and
• "To avoid confusion" etc., because this is clarified above.

Anthony (talk) 12:40, 17 September 2009 (UTC)

Focusing on humans

There are many good things about this article, but its major problem (in my view) is the constant implicit focus on human beings as the sole objects of this topic. Apart from a brief few lines at the end, this article suffers (no pun intended) from extreme anthropocentrism. Pain is not something specific to our species; rather, it is something we experience because we happen to be animals. I would recommend rewording and/or reorganising the article, so as the show the aspects of pain shared by all animal beings (humans included), followed by subparts dealing with specifically human aspects (insofar as it may make sense to speak of specifically human forms of pain). Aridd (talk) 13:23, 28 January 2008 (UTC)

I agree that for nociception the article would be better if it focussed on animals. But for pain we have a problem - pain is defined as an experience and by long convention humans attribute experiences to each other - we act as if we knew what was happening experientailly for another human. With animals doing this is considered "non-scientific" and "anthropomorphising". Science in general takes the view that we can only infer the experience of pain in non-human animals. (That we can cognitively only infer the experience of other human is perhaps not promoted widely by scientists as doing so would be politically destructive of a career and seen as Nazi/inhumane/immoral/unethical.) Which means that most of the avaiable info on pain is on human pain. If you have the time and inclination to find well sourced material on animal pain then please bring it here so we can find a way to include it in Wikipedia. SmithBlue (talk) 00:29, 20 March 2008 (UTC)

Panksepp, a leading scientist on emotions, believes that "[o]ther mammals do have affective experiences." (p.31, 2005, Consciousness and Cognition 14, pp.30-80) However, "Panksepp's common sense view of affective neuroscience is not the commonsense view in large areas of neuroscience" according to Watt (pp. 81–88). It's a controversial topic, still to be resolved. Admittedly, pain is a construct that has probably been used more in reports of studies on humans than on animals. However, the literature on animals and this particular form of "aversive stimulus" is abundant. The scientific study of pain, let alone emotions, is a young and still emerging field.Ostracon (talk) 19:28, 16 August 2009 (UTC)

As the author referenced in the above comments, I would have to strongly agree that the piece, in trying to follow the traditional standard of avoiding anthropomorphism at all costs probably commits the opposite sin of anthropocentrism. One way of conceptualizing pain (unfortunately not presented in this article) is that it is the homeostatic mandate to avoid tissue damage. Obviously, this mechanism presumably emerges quite early in evolution and probably has many non-conscious antecedents (perhaps in terms of simple avoidance mechanisms in organisms lacking nervous systems).

In terms of the actual neurobiology of pain, we share an enormous amount of conserved fundamental architecture with all mammals, and even with many if not most vertebrates. This suggests that a primitive experience of pain may exist in all vertebrates. The problem with the science here is the requirement for the so-called 'gold standard' of verbal report to verify a conscious experience. In other words, if the gold standard is that a creature has to be able to describe experience in words, this means of course that pain as a subjective experience has to be confined to humans. However, many in behavioral neuroscience question whether this standard is really the best possible one. Certainly in every mammal studied, the fundamental homologies in terms of subcortical and paleocortical neural systems involved in pain, behavioral and vocal expressions in relationship to pain, chemoarchitectures that modulate pain, pharmacological relief from pain, and virtually every other biological issue that one can think of are so compelling that commonsense suggests that animals, particularly mammals, do feel some version of pain. It becomes somewhat more controversial in 'lower' vertebrates, but again the homologies are impressive there as well. Our speciesism (our widespread 'scientific' tendency to overestimate our specialness and underestimate our fundamental continuities with the rest of the animal kingdom) have long been rationalized in terms of the creed that "we must avoid anthropomorphism".

However there are signs that this whole set of issues is changing, and I believe it is fundamentally related to a growing sense that consciousness itself is a distributed property of the animal kingdom, and hardly unique to humans. Again, if we define consciousness in terms of its highest cognitive extensions particularly in relationship to verbal communication, we close the door on the animal kingdom, but if we move our definition away from exclusively cogno-centric conceptualizations to include virtually any form of an inner world, consciousness looks like it emerged rather early in evolution. It makes perfect sense that pain emerged rather early also coincident with a primitive form of sentience, as the aversion to tissue damage would be powerfully selected, indeed it would have to be selected virtually above all else, if animals were to survive and procreate. At this point, we have a widespread consensus, even encoded into the law in many societies, that physical abuse of animals (which of course is likely to inflict severe pain on the animal) is no longer tolerated. This suggests that anyone who doubts the existence of some form of pain in animals is sadly missing fundamental realities. 76.24.52.9 (talk) 16:20, 6 December 2009 (UTC) Douglas F. Watt, Ph.D.

I more or less agree with all of that, but I don't see clearly what specific changes in the article you are arguing for. (As an unrelated practical matter, I encourage you to use edit summaries for your edits, especially when responding to comments near the top of a talk page -- it took me a bit of work to figure out which part of this page you had edited.) Regards, Looie496 (talk) 17:36, 6 December 2009 (UTC)

No argument from me. Feel free to make changes. Discuss them here beforehand if you like, or just go for it. Anthony (talk) 18:51, 6 December 2009 (UTC)

Introductory definition

"Physical pain is the unpleasant feeling common to a headache and a stubbed toe" - A definition constructed out of examples?! I guess this needs to be re-constructed.

It's hard. We are certainly open to concrete suggestions. Regards, Looie496 (talk) 01:31, 22 September 2009 (UTC)

Hi Looie496. That was me who dumped those paragraphs on neuroscience. Sorry, I was on a university computer and forgot to sign in. Don't worry, they wouldn't have gotten lost. Presently, just about all I think about is the difficulty of defining pain, and its neural correlates. I am compiling info' on these two topics from text books and reviews. When I am satisfied I've got it covered I'll post a paragraph on the dilemma of defining pain, and a readable and concise description of pain in the nervous system here in the talk page for ideas and criticism before adding them to the article. How's my "Evolution of the theory" for readability? Anthony (talk) 11:26, 22 September 2009 (UTC)

By the way. The OneLook.com quick definition of "yellow" is ▸ noun: the quality or state of the chromatic color resembling the hue of sunflowers or ripe lemons. That is, examples of stimuli that evoke yellow are used. The problem of defining pain is analogous to that of defining color. Anthony (talk) 11:40, 22 September 2009 (UTC)

Merskey thinks there is pain (emerging from physical or emotional causes) and metaphorical (or mental) pain. From Harold Merskey's 1978 "Pain and Personality" in R. A. Sternbach's The Psychology of Pain, pp. 111-2:

"... when we speak of pain we mean an experience which is located in the soma. It may or may not have a physical cause. Jeremiah's pain (Lamentations I, 12) is described as entirely due to emotions. But it is referred to the body, located in the bones... Any such experience of pain, however, has to be distinguished from the purely metaphorical notion of pain: anguish, sorrow, misery, distress, etc. are not words which necessarily indicate any felt somatic disturbance. Mental pain is a different concept from pain and has to be kept separate."

What distinguishes pain from metaphorical pain is the location of the former "in the soma". Until now we have made the distinction by using "physical pain" for non-metaphorical pain but this term may seem to exclude "functional" pain - pain caused by psychological trauma or pain of unknown origin. I propose we follow Merskey and use "pain located in the body" rather than the potentially confusing "physical pain", and have altered the introduction accordingly. Anthony (talk) 12:38, 2 October 2009 (UTC) On second thoughts, that looks way to clumsy. But I'm still very unhappy about "Physical pain" for the above reasons, so have replaced it with "Pain", since any ambiguity is eliminated by the sentence immediately preceding the Intro'. Anthony (talk) 12:49, 2 October 2009 (UTC)

Defining pain is notably difficult. I think the sensory aspect and the unpleasant aspect must necessarily be present, and examples cannot suffice. Physical pain should be kept as the appropriate expression for referring to pain in this article. Moreover, the section on terminology cannot remain like it is now. In some ways it is better than before, but in others it is worse. Nociception should definitely not have been removed, because it is a source of confusion for many. Let's discuss and/or make some changes. --Robert Daoust (talk) 02:33, 13 October 2009 (UTC)

Hi Robert

1. You're right, Terminology should discuss the distinction between "nociception" and "pain". I removed it because it was repeated in the section below, Mechanism. But I was being clumsy. Have replaced.
2. Examples by no means suffice. The introduction contains affective-motivational (negative affect, aversion), sensory-discriminitive (location, duration, intensity, quality) and cognitive dimensions.
3. Can you elaborate on your preference for "physical pain" over Merskey's "pain located in the body" please?
   

Anthony (talk) 10:12, 13 October 2009 (UTC)

As with all complicated definitions, we should start with something very simply and then have the article flesh out whatever else is needed. The first sentence should be direct, for example "Pain is an unpleasant physical or mental sensation caused by injury or illness." Rajrajmarley (talk) 04:35, 13 October 2009 (UTC)

Hi Rajrajmarley,

1. I concur. The introduction should be as simple as possible, without sacrificing accuracy. All those items in parentheses are a bit much, and can be included somewhere in the text below. I've just removed most of them.
2. "Sensation" is problematic, for reasons outlined above in the discussion.
3. Pain can exist in the absence of illness or objectively detectable injury. Illness or injury can evoke unpleasant feelings that are not pain (nausea, itch, etc.).
   

Anthony (talk) 10:12, 13 October 2009 (UTC)

Merskey's description might be good as a commentary but not in a banner. The expression 'physical pain' is the one widely preferred by common usage for referring to the topic of this article, and pain in the sense of suffering is 'metaphorical' only within the perspective of a physical pain discourse. Given that it must be clear to readers what this article is about, I think appropriate to open the lead with Physical pain is... --Robert Daoust (talk) 13:02, 13 October 2009 (UTC)

Sold Anthony (talk) 13:50, 13 October 2009 (UTC)

I agree. Rajrajmarley (talk) 02:45, 14 October 2009 (UTC)

I'm thinking about moving the third paragraph

Pain is part of the body's defense system, producing a reflexive retraction from the painful stimulus, and tendencies to protect the affected body part while it heals and avoid that particular harmful situation in the future.

from the intro' down to replace the first sentence in Evolutionary and Behavioral Role. Any thoughts? Anthony (talk) 13:12, 14 October 2009 (UTC)

Good idea. And then we should put up a paragraph summarizing the article a bit. --Robert Daoust (talk) 15:57, 14 October 2009 (UTC)

That makes sense to me. Do you mean to begin the body of the article with such a paragraph or end the Intro' with it? I'd prefer to see it at the beginning of the article, myself. Anthony (talk) 05:40, 15 October 2009 (UTC) On second thoughts, I'm easy. Something like "This article discusses..." would be cool in the intro'. Anthony (talk) 05:56, 15 October 2009 (UTC)

Introduction II

I like it all, Robert. I'd never read WP:LEAD and this conforms nicely. Well done. I'd been feeling bad about "It is often accompanied by..." since it was not followed up in the body of the article. Swapping "unpleasantness" for "negative affect" was a very good move. My only suggestion is: How about removing the 3 words "Given its significance" from the 4th paragraph? It seems redundant to me. Anthony (talk) 16:50, 8 November 2009 (UTC) Also, I tried to follow the link "National Pain Education Council" at ref. 5 and it took me to a login page. But when I click on "Register Now" I get "An error occurred on the server when processing the URL. Please contact the system administrator." Is it working from your end? Anthony (talk) 17:07, 8 November 2009 (UTC)

Link not working for me either. Intro would have to reflect, summarize the article body more... I am going out now. --Robert Daoust (talk) 17:35, 8 November 2009 (UTC)

Regarding that dead link, Turk and Dworkin (both eminent pain researchers and theorists) say here "Nearly one-half of Americans who seek treatment with a physician report that their primary symptom is pain." A less dramatic claim than the National Pain Education Council's claim that pain prompts "half of all Americans to seek medical care annually." This makes me nervous about the latter and I would like to see some sound support for it if it is to stay. Anthony (talk) 19:10, 8 November 2009 (UTC)

What about changing the first 3 sentences from:

Physical Pain is a sensory and emotional experience that typically consists of unpleasantness and aversion. It is a feeling common, for instance, to a headache and a stubbed toe. It has location, duration, intensity and a distinctive quality (e.g., burning, stabbing, dull).

To:

Physical Pain is a sensory and emotional experience that typically consists of unpleasantness and aversion, with a location, duration, intensity and distinctive quality (e.g., burning, stabbing, dull). It is the feeling common to a headache and a stubbed toe.

That is, have motivational/affective followed by sensory discriminitive, followed by examples. And change the indefinite article a to the definite the, in the same way that red is defined as the colour of tomatoes and blood. And for instance looks redundant, to me . Anthony (talk) 14:59, 11 November 2009 (UTC)

On pain as a reason for medical consultation, claims should be backed with primary sources, of course. I am not satisfied with what I have found right now, but it should not be hard to get a clear picture. Meanwhile, Turk is better. As to the lead, I would incline toward:

Physical Pain is a sensory and emotional experience that typically consists of unpleasantness and aversion. It has location, duration, intensity and a distinctive quality (e.g., burning, stabbing, dull).

I am not sure about how to turn the examples sentence. And a big question is what makes nausea or severe itch non-examples of pain! --Robert Daoust (talk) 16:59, 11 November 2009 (UTC)

I don't think "consists of unpleasantness and aversion" is right -- pain consists of more than that. This only captures the affective dimension. Pain also has a physical dimension that depends on specific receptors and neural pathways. Nausea and itch depend on different receptors and pathways. Looie496 (talk) 18:24, 11 November 2009 (UTC)

O.K., Robert, I'll change the National Pain Education Council claim to Turk and Dworkin's and cite them.

On the distinction between pain, nausea and itch: Nausea is what you feel just before you vomit, itch is the aversive feeling on the skin which is relieved by scratching, and pain (in the narrow, physical sense) is what you feel when you stub a toe, or dip your arm into a vat of boiling oil. That is, the thing itself is a subjective experience and, like the experience of red, cannot be described per se - it's pre-language - but can be distinguished only by the stimuli that evoke it or the behaviors it provokes. Examples of pain-evoking stimuli are as necessary to the definition of pain as examples of red- and yellow-evoking stimuli are to the definition of red or yellow. It is how qualia are defined. It is the problem of other minds. Although pain, nausea and itch may be caused by the same stimuli in both of us, and evoke the same physiological. neurological and behavioural responses in both of us, your pain/nausea/itch itself, what it is to you, I can never know.

Are you saying, Robert, that intense itch and nausea are indistinguishable from the pain of a stubbed toe? I can only say that's not my experience. Intense nausea is just intense nausea and always qualitatively different from the pain of a stubbed toe. One's nausea. The other's physical pain.

I agree, Looie496, that "consists of unpleasantness and aversion" is wrong. How about:

Physical pain is an unpleasant and aversive sensory and emotional experience, located in the body, of discernible intensity, duration and quality (dull, sharp, burning, etc). It is the feeling commonly felt by humans when they stub a toe (mechanical), burn a finger (heat), get chilli-powder in the eye (chemical) or stick a finger into a light socket (electrical).

I realise the examples are far too vulgar, but how's the general thrust? Anthony (talk) 20:21, 11 November 2009 (UTC)

Can I remove "In medicine" and "considered as" from:

In medicine, pain is considered as highly subjective. A definition that is widely used in nursing was first given as early as 1968 by Margo McCaffery: "Pain is whatever the experiencing person says it is, existing whenever he says it does".

and move it from the top of the second paragraph to the bottom of the first; since, like the rest of the first, it is about definition; and the second paragraph begins to deal with the article? Anthony (talk) 20:58, 11 November 2009 (UTC) Or, how about changing it to:

A definition reflecting the subjective nature of pain, and widely used in nursing, was introduced by Margo McCaffery in 1968: "Pain is whatever the experiencing person says it is, existing whenever he says it does."

Anthony (talk) 21:11, 11 November 2009 (UTC)

Latter suggestion is good! As to the 'general thrust', I am afraid it is too 'original research', but I like it and we probably could find something in that direction, and in relation also to Melzack's three dimensions, and with a mention of specific receptors and pathways as noted by Looie. --Robert Daoust (talk) 00:35, 12 November 2009 (UTC)

Re: Receptors and pathways. What about:

It can be generated by stimulation of pain receptors in the peripheral nervous system or by damage to or malfunction of the peripheral or central nervous systems.

Re: Melzack and Casey's 3 dimensions of pain. This formulation

Pain is an unpleasant and aversive sensory and emotional experience, located in the body, and characterized by discernible intensity, duration and quality

describes the first two dimensions. "Unpleasant and aversive" describes the affective-motivational dimension. "Location, duration, intensity and quality" is the breakdown of the sensory-discriminitave dimension used since Melzack and Casey (1968) and, possibly, earlier. As for the cognitive dimension, how about including

Cognitive activities such as appraisal, cultural values, distraction and hypnotic suggestion (from Melzack, R. (1986) Neurophysiological foundations of pain, in Sternbach,R.A. (Ed.) The psychology of pain, Raven Press New York) can have a profound effect on the experience of pain and may modulate the level of unpleasantness and aversiveness as well as pain's perceived intensity.

The only way I can see of distinguishing pain from itch is to offer examples. —Preceding unsigned comment added by Anthonyhcole (talk • contribs) 07:27, 12 November 2009 (UTC)

Examples are helpful of course, but itch is basically a different type of sensation from pain as much as touch is, see this review and this review. Looie496 (talk) 17:25, 12 November 2009 (UTC)

Thank you Looie496. What an excellent couple of reviews. (They both rely on Bud Craig for the dedicated pain and itch neurons in the spinothalamic tract, though, as do the few others I've read on this. I wonder if anybody has replicated his work. It is such a crucial point. Personally, I don't doubt the specificity for one second. It would be nice to see it replicated by an independent team, though.) My problem is with the present iteration of the definition. If it didn't begin with "Pain is" you couldn't tell whether it was defining itch or pain (it is too inclusive):

X is an unpleasant and aversive sensory and emotional experience, located in the body, and characterized by intensity, duration and quality. Cognitive activities such as appraisal, cultural values, distraction and hypnotic suggestion can have a profound effect on the experience of x and may modulate the level of unpleasantness and aversiveness as well as its perceived intensity.

The IASP uses "associated with actual or potential tissue damage, or described in terms of such damage" but this is too narrow. It excludes any pain which is not associated with tissue damage or described using terms such as crushing, burning etc. I think the above definition is accessible, accurate, concise and derived directly from classic theory, and with the addition of a couple of examples would be comprehensive, while excluding itch, nausea, anxiety, etc. Anthony (talk) 20:59, 12 November 2009 (UTC) How about this?

Pain is the unpleasant and aversive feeling common to such experiences as a stubbed toe, a headache, a burnt finger, and salt in a wound. It is characterized by location, intensity, duration and quality. Pain can be generated by stimulation of pain receptors in the peripheral nervous system or by damage to or malfunction of the peripheral or central nervous systems. Cognitive activities such as distraction, appraisal, cultural values, and hypnotic suggestion can modulate the intensity and unpleasantness of pain.

Anthony (talk) 22:23, 12 November 2009 (UTC)

Groping around: "Pain is an unpleasant sensory experience. It has a certain location, intensity, and duration. A stubbed toe, a headache, a burnt finger are common examples of pain. Neurologically, pain can be generated by stimulation of nociceptors or by damage to or malfunction of the peripheral or central nervous systems. Cognitive activities such as distraction, appraisal, cultural values, and hypnotic suggestion can modulate the intensity and unpleasantness of pain.

(The above paragraph was contributed by Robert)

I hope this isn't too tedious for you, Robert. It's my idea of fun.

Affective/motivational dimension. I represented this dimension with "unpleasant" and "aversive", but you have dropped "aversive". "Aversion" (motivational) is, I believe, indispensable, if we're going to adhere to the classic, Melzack, Wall, Casey, view of pain. So I'd be in favour of retaining it (even though, to the average reader, not familiar with the neurological and psychological distinction between affect and motivation, it may seem to be tautology or redundancy).

Sensory/discriminitive dimension. I notice you have dropped "quality". I'm OK with that, since "quality" appears in less than an eighth of the discussions I've read about the sensory/discriminitive dimension ("intensity", "location", and "duration" occur in all of them). So do we agree to let "location, intensity and duration" represent the sensory/discriminitive dimension?

In your "It has a certain location, intensity, and duration," I think "certain" is a worry, because in some instances of somatic pain and most instances of visceral pain the location and intensity are vague, and in some pathological cases, nonexistant. I suggest we use "Typically, it is characterized by intensity, location, and duration."

The examples. I used "headache", "stubbed toe" , "burnt finger" and "salt in a wound"' to represent the two major categories of pain - neuropathic (headache) and nociceptive - and the three major categories of nociceptive pain: mechanical (stubbed toe), thermal (burned finger) and chemical (salt in a wound). You have dropped "salt in a wound". I understand it is clumsy but, for completeness, I'd like to see it (or chili powder/pepper spray in the eyes, or some other example of chemically-induced pain) retained.

Common to. The examples are here so that we can point to experiences that almost all readers have had and say "pain is what they all have in common"; as, in defining "yellow", we say it is the color common to ripe lemons and buttercups. I believe my formulation - "Pain is the unpleasant and aversive feeling common to such experiences as a stubbed toe, a headache, a burnt finger, and salt in a wound" - says this. My concern with yours - "A stubbed toe, a headache, a burnt finger are common examples of pain" - is that they are not examples of pain, they are examples of situations involving pain. Pain is the unpleasant and aversive feeling common to those situations.

Neurologiy. You have added "Neurologically," to "pain can be generated by stimulation of nociceptors or by damage to or malfunction of the peripheral or central nervous systems." I think that is redundant, since the rest of the sentence is all about neurons.

So, I propose this for the opening paragraph:

Pain is the unpleasant and aversive feeling common to such experiences as a stubbed toe, a headache, a burnt finger, and salt in a wound. Typically, pain is characterized by its intensity, location and duration. It is initiated by stimulation of nociceptors in the peripheral nervous system, or by damage to or malfunction of the peripheral or central nervous systems. The presence of pain, its intensity, and the degree of unpleasantness are all determined by more than just the intensity of the painful stimulus. For example, cognitive activities such as distraction, appraisal, cultural values, and hypnotic suggestion can significantly modulate pain's intensity and unpleasantness. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage". A definition widely used in nursing, emphasizing the subjective nature of pain and the importance of believing patient reports, was introduced by Margo McCaffery in 1968: "Pain is whatever the experiencing person says it is, existing whenever he says it does".

Anthony (talk) 08:44, 14 November 2009 (UTC)

I am more familiar with iodine or peroxide than salt in wounds! Your last version seems good enough to replace the present one. Is it possible to shorten, avoid repetion, make only one sentence with "The presence of pain, its intensity, and the degree of unpleasantness are all determined by more than just the intensity of the painful stimulus. For example, cognitive activities such as distraction, appraisal, cultural values, and hypnotic suggestion can significantly modulate pain's intensity and unpleasantness. "? --Robert Daoust (talk) 19:13, 14 November 2009 (UTC)

It is long. I'll work on it. Anthony (talk) 06:06, 15 November 2009 (UTC) I have removed "The presence of pain, its intensity, and the degree of unpleasantness are all determined by more than just the intensity of the painful stimulus. For example," Anthony (talk) 12:49, 15 November 2009 (UTC)

I think I prefer "iodine in a cut" to "salt in a wound". Anthony (talk) 19:21, 6 December 2009 (UTC)

Archive?

Would the end of the year be a good time to archive the above? Anthony (talk) 06:19, 12 December 2009 (UTC)

Yeah, and User:WhatamIdoing did it last time (you may want to let her know). Also, when someone (you?) does (do?) this, you might want to change "through 2007" and "through 2008" to "2007" and "2008" for clarity. Mononomic (talk) 16:31, 12 December 2009 (UTC)

Redirect Gate control article to here

Everything in the gate control article is said here but more concisely and accurately. Thoughts? Anthony (talk) 07:48, 16 December 2009 (UTC)

Might as well redirect then. It deserves a separate article, but there is no sense in having one until there is extra material for it. Looie496 (talk) 17:08, 16 December 2009 (UTC)

Move Pain in the nervous system from Chronic pain to here?

I'd like to move it here to form the beginnings of a section on the neurofunction and neurochemistry of pain. I believe it is out of place in Chronic pain, as it stands. Though, a lot of it could go back later as part of a discussion of theories about the neural bases of pain chronicity. Thoughts? Anthony (talk) 07:45, 23 December 2009 (UTC)

I agree that the material doesn't currently include any information that relates it specifically to chronic pain as opposed to pain in general. Looie496 (talk) 15:10, 23 December 2009 (UTC)

Done Anthony (talk) 13:41, 24 December 2009 (UTC)

Move Evolution of the theory to its own article

I suggest doing the above (and redirecting Gate control theory of pain to that article), leaving:

A-delta and C peripheral nerve fibers carry information regarding the state of the body to the dorsal horn of the spinal cord. Some of these A-delta and C fibers, called nociceptors, respond only to painfully intense stimuli, while others do not differentiate noxious from non-noxious stimuli. Dedicated fibers in the spinal cord carry A-delta and C fiber pain signals from the dorsal horn, up the spinal cord and brain stem, to the thalamus in the brain. Pain-related activity in the thalamus spreads to the insular cortex (thought to embody, among other things, the feeling that distinguishes pain from other homeostatic emotions such as itch and nausea) and anterior cingulate cortex (thought to embody, among other things, the motivational element of pain); and pain that is distinctly located also activates the primary and secondary somatosensory cortices.

as the beginning of a section on the neural anatomy of pain. Anthony (talk) 13:41, 24 December 2009 (UTC)

I removed "nociception" from Terminology

I removed:

Nociception, the unconscious activity induced by a harmful stimulus in sense receptors, peripheral nerves, spinal column and brain, should not be confused with physical pain, which is a conscious experience. Nociception or noxious stimuli usually cause pain, but not always, and sometimes pain occurs without them.

because the same point:

Nociception is the unconscious afferent activity produced in the peripheral and central nervous system by stimuli that have the potential to damage tissue. It should not be confused with pain, which is a conscious experience.

is made in the section beneath it, Mechanism. I don't care for the bullet-point list of terms, and think their meanings should be explained and usage clarified as the concepts they represent are introduced in the article. Anthony (talk) 15:13, 24 December 2009 (UTC)

I see what you mean, Anthony. Section Terminology was useful in the past, when it was awfully not clear yet if this article was about pain or nociception or suffering. I agree it should now be dissolved in the way that you suggest. By the way, congrats again for your work. I have three little suggestions: 1) have something in the intro about acute and chronic pain; 2) put McCaffery's definition somewhere else than in intro; 3) examples of pain in intro should include a neuropathic pain, shouldn't it?, and iodine in a cut should replace salt in a wound (I'll replace it myself)... (those examples are apparently a great source of inspiration for vandals, a sure sign that they are valuable as a communication device!) --Robert Daoust (talk) 17:17, 24 December 2009 (UTC)

And it is a very handy place to plop the definitions of chronic and acute!
1) I'd appreciate your thoughts on this:

Pain is essential to survival. It motivates us to withdraw from potentially damaging situations, protect damaged body parts while they heal, and avoid the situation in future. Most pain resolves promptly once the painful stimulus is removed and damage has healed but, sometimes, pain persists despite removal of the stimulus and apparent healing of the body; and pain sometimes arises in the absence of any obvious stimulus or damage.

It gets the core evolutionary explanation in there, it avoids using "chronic" and "acute" because of their ambiguity, and (I think very importantly, because of general ignorance of its existence and disbelief in its actuality) includes idiopathic pain. I realize the language is simple, but I think that is a virtue.
2) Agree.
3) I was thinking headache is neuropathic, but could be completely wrong. I know nothing about headache theory. Anthony (talk) 14:04, 25 December 2009 (UTC)
By the way, the reason I want to ditch Evolution of the theory is, by the time I had finished researching it I realised how irrelevant (and wrong) it all was. It deserves an article, but I think it just confuses things and takes up too much room here. Anthony (talk) 14:13, 25 December 2009 (UTC)

1) Your suggested paragraph seems excellent to me. It would be perfect with references that support the assertions. 3) I did not check lately, but the cause of headache, if I remember well, is still not known for sure, and a popular theory says that it would involve nociceptors in swelled blood vessels. In any case, I guess that neuropathy is a 'chronic' ill state of the nerves, so that an occasional headache is surely not neuropathic (unless there is such a thing as a 'passing' neuropathy). It seems that deep somatic pain and visceral pain are of the mechanical (swelling) or chemical (components of inflammatory fluids) kinds. My suggestion of adding an example of neuropathic pain is perhaps not well advised, because if we want to be exhaustive in representing the different kinds of pain, we may have just too many examples... Already we have dropped 'electrical' pain... All this seems important to me because definition by examples is a risky move, especially in the face of the challenge posed by 'vandals': there ought to be a good reason for justifying the chosen examples and only those chosen examples...

About the section Evolution of the theory, I am not sure of what you mean. Much of it includes important and valuable material, in addition to more or less wrong aspects. If it deserves an article, it certainly deserves a section here. Perhaps it would be easier if the section was just titled "Theories"? --Robert Daoust (talk) 04:27, 26 December 2009 (UTC)

1) I've linked to some neurology textbooks. 3) We could just use thermal, mechanical and chemical examples. I can't think of any common example of neuropathic. I noticed the absence of electrical but, because it seems able to activate any nociceptor, regardless of modality, by bypassing the receptor and just shoving potential down the fiber, and rarely occurs in nature (except when you're eel fishing) I thought I'd leave it out for concision. But I believe it deserves detailed treatment in the article, eventually - as does inflammatory (a supposed sub-class of chemical, I think).
As for the historical development of pain theory, I just don't see the point. People will come here to find out what pain is. I'd like to see a clear accessible synopsis of what science currently agrees on; with a "see also" link to the history. I'm working on two sub-sections at the moment. One about classification of pain and another about physiology, neural anatomy and function, and psychology.
I've made the changes we discussed above. Anthony (talk) 11:10, 26 December 2009 (UTC)
3) Striking your funny bone is neuropathic pain. Should I include that as an example in the intro? Anthony (talk) 17:38, 28 December 2009 (UTC)

Rewrote Pain In Healthcare

I removed the following, because they just seemed to be a litany of definitions randomly thrown in there, a bit of neuroanatomy, and a discussion of referral and radiation - none of which belong in this section:

Pain assessment may also draw upon the concepts of pain threshold, the least experience of pain which a subject can recognize, and pain tolerance, the greatest level of pain which a subject is prepared to tolerate.

The above is unreferenced and I can't find any mention of pain threshold being used in the clinical setting.

Among the most frequent technical terms for referring to abnormal perturbations in pain experience, there are: allodynia, pain due to a stimulus which does not normally provoke pain, hyperalgesia, an increased response to a stimulus which is normally painful, hypoalgesia, diminished pain in response to a normally painful stimulus.

Anesthesia is the condition of having the feeling of pain and other sensations blocked by drugs. It may involve complete unawareness or reduced awareness of the entire body (i.e., general anesthesia), or a total or partial lack of awareness of a part of the body (i.e., regional or local anesthesia).

The endogenous central analgesia system is mediated by three major components: the periaqueductal grey matter, the nucleus raphe magnus, and the nociception-inhibitory neurons within the dorsal horns of the spinal cord, which act to inhibit nociception-transmitting neurons also located in the spinal dorsal horn. Peripheral regulation consists of several different types of opioid receptor that are activated in response to the binding of the body's endorphins. These receptors, which exist in a variety of areas in the body, inhibit firing of neurons that would otherwise be stimulated to do so by nociceptors.

Localization is not always accurate in defining the problematic area, although it will often help narrow the diagnostic possibilities. Some pain sensations may be diffuse (radiating) or referred. Radiation of pain occurs in neuralgia when stimulation of a nociceptor at one site is perceived as pain in the sensory distribution of that nerve. Sciatica, for instance, involves pain running down the back of the buttock, leg and bottom of foot that results from compression of a nerve root in the lumbar spine. Referred pain usually happens when sensory fibers from the viscera enter the same segment of the spinal cord as somatic nerves, i.e., those from superficial tissues. The sensory nerve from the viscera stimulates the nearby somatic nerve so that the pain localization in the brain is confused. A well-known example is when the pain of a heart attack is felt in the left arm rather than in the chest.

Anthony (talk) 17:46, 28 December 2009 (UTC)