Normal, Abnormal, and Dysfunction

[BB]

I'm often troubled when reading through the various articles that describe adaptive processes as normal or abnormal. Of course this is all relative. And the nervous systems NORMAL response is to become hypersensitive at times. Nonetheless, this is often described as being abnormal. I even occasionally see it described as pathophysiology.

So, my question is: What defines normality, abnormality, and dysfunction when speaking of the adaptive responses of the nervous system?

[EricM]

Normal - processes that lead towards homeostasis.
Abnormal/pathological - processes that lead toward the opposite of homeostasis (what is that? homeostatic imbalance?).

A normal process, could become abnormal if not shut off at an appropriate time.

But that's just a stab at it Cory.

[christophb]

Interesting thread... I have no idea but I've been wondering this myself.

Cory, do the articles state that the nervous system is normal/abnormal/dysfunctional, or are they talking about tissue and joints?

[BB]

nervous system

Such reasoning appears to be at odds with
the current consensus of scientific opinion, which suggests
that the mechanisms underlying SNS contributions to pain
are likely to occur more as a result of neurophysiological
coupling between the SNS and sensory nervous systems and
abnormal sensitivity to normal sympathetic activity rather
than from any abnormal functioning or overactivity of the
SNS itself [28,29].

This is the article to most recently get me thinking on this.

What amount of sensitivity is normal? What is normal sympathetic activity?

I like your thought, Eric, on moving towards and away from homeostasis. How could you tell if the increase in sensitivity was a movement toward or away and thus determine normal or abnormal, however?

[EricM]

How could you tell if the increase in sensitivity was a movement toward or away and thus determine normal or abnormal

I was hoping you knew.

I had a zoom-in lens on when first thinking of this. It might help to zoom-out for the alien view as well.
If there is a given level of sensitivity that does not change in an adaptive direction in response to changes in conditions that should influence that sensitivity, I would call that abnormal. I don't know how you would detect that clinically apart from trial and error.

[Bas Asselbergs]

I am almost tempted to call nothing (other than a clear nervous system disease )abnormal or dysfunctional. Is the hypersensitivity an abnormal process? Or is it a "normal" response to extra-ordinary input/process/output? For instance, the effects of socio-cultural-stress etc etc influences on our nervous system processes (and potential hypersensitivities) are not attributable to the system itself.

My my. I think I mean that speaking for adaptive processes of the nervous system, I really have to consider only a true disease process OF the nervous system as dysfunction or abnormal......

(Maybe I should go for that cup o' joe....)

[Jon Newman]

Normal could be defined from many standpoints but an important distinction might be that for the individual or that for the population.

Dysfunction also has different targets and one attempt to resolve it is through the changing language of disablement.

I think processes are what they are and Eric's statement of whether they serve homeostasis (or desired growth and development) is a reasonable way of describing whether they are helpful.

I think the sentence quoted by Cory could be rewritten, without losing much of the meaning, as

Such reasoning appears to be at odds with
the current consensus of scientific opinion, which suggests
that the mechanisms underlying SNS contributions to pain
are likely to occur more as a result of neurophysiological
coupling between the SNS and sensory nervous systems and
undesired sensitivity to normal sympathetic activity rather
than from any abnormal functioning or overactivity of the
SNS itself

unless we have a way of classifying normal sensitivity for both populations and the individual before us. Is that too post-modern?

[Bas Asselbergs]

I like that link Jon. It helps to look at this "normal" issue in a different light.
Maybe we should really drop the whole dysfunction, ab- and normal terminology, and move towards "disablement due to" neural adaptive processes....?

[BB]

Great points.

The phrase "disablement due to adaptive neurologic processes" is a definite improvement. However....

Pain is meant to bring about disablement sometimes and therefore even disablement does not really give us a nice delineation between what is implied by normal and abnormal. For example, the pain and disablement of a broken arm are adaptive as they keep you from further injuring the damaged tissues.

"undesired sensitivity"

This seems to be a good path. What makes it undesirable? My mind keeps taking me to "adaptive" and "maladaptive." I don't think such things can likely be determined at the level of local physiology but only in terms of the behavior of the organism.

This brings up another term: pathophysiology. This term implies a pathological process. However, I often see this term used to describe a normal adaptive process through normal physiologic responses that is bringing about an undesired effect. If the term is used to describe the physiology that results from a pathological event, such as tissue damage, then that's different. But, that is not how I see it used commonly.

[Line M]

It took me some time to read this interesting thread over and over.
Confusion for me is that the discussion is shifting from level to level and it depends on what level one aims: is it cellular level, tissue level, functional level, system level you describe the normality/abnormality.

"undesired sensitivity" What makes it undesirable?

Undesired from which point of view: the mind hates it, the cell probably loves it, the moving away and towards which has been described earlier by Eric

I often see this term used to describe a normal adaptive process through normal physiologic responses that is bringing about an undesired effect. If the term is used to describe the physiology that results from a pathological event, such as tissue damage, then that's different

I can only see a difference, that in the first case the outcome is pathophysiological and the latter the input is. On level of action potential everything is normal.

[Luke Rickards]

Great stuff.

I might be interesting to consider aging here too. Are the tissue changes associated with aging normal or pathological?

[EricM]

It seems easy to consider 2 dichotomous entities, pathological and non-pathological. Yet, I think we often encounter persistent, non-pathological problems which resemble pathological ones. Is this a valid third category?

[christophb]

This thread has my head spinning...

Could there be pathological problems that resemble non-pathological ones (well adapted)? I see a lot of gymnasts with pars fractures. Not all report back pain... yet they have a fracture.

[Barrett Dorko]

Last time I looked up the word "pathology" it said, "the presence of disease." That's no help to us.

For our special purposes perhaps we need to simply define "pathology" as something that requires healing and/or repair in order to no longer be considered "pathological." In that case, nothing is necessarily implied about the presence of pain and/or dysfunction (which is distinct from disability).

[Diane]

It all reminds me of the merry-go-round conversation about how to classify neurogenic pain as opposed to neuropathic pain, when in fact there is a degree of overlap.

[nari]

What about the word anormal which implies, according to OED, a deviation from normal (or expected)but not necessarily abnormal.

Of course that leaves the definition of normal hanging in midair, but that has always been the case, clinically. It arises from our need to classify things according to set rules,and the human construct doesn't follow set rules very well.

Nari

[BB]

I think that we can use the term "pathology" at the local tissue level. As Barrett said, something that requires healing. It doesn't imply a process. To me, it implies the result of an event or process.

In terms of physiology, it seems the terms adaptive and maladaptive could be used. Would anything other than a lack of a response be considered maladaptive though?

In terms of behavior, maybe we should consider a distinction between disablement and dysfunction. Disablement, as I mentioned earlier, is often adaptive. Dysfunction however, I see to mean a maladaptive disablement.

Am I just creating word soup here?

[Diane]

What color could we designate the "flags" that indicate a-normal, I wonder?
Turquoise would be my pick.

Today I treated a young guy for the second time, post MVA. He seemed uncomfortable, and distracted. I checked to see if it was my handling, but he seemed ok with it.. just distant. Finally he confessed he hadn't eaten breakfast and was anxious for the session to be over so he could go get food - he was in pain all right, hunger pain.
He was busy with trying to keep from bolting the session entirely in order to consummate a deeper biological drive/need state.

I guess this could be an example of something "anormal" ... it was a confusing signal he was sending and I was receiving. I could see there was a flag, just couldn't figure out the color.

[nari]

As anormal suggests a heightened sensitivity state, perhaps it sits with a pale yellow colour. What colour would homeostasis be? White or green?

Is a cut finger a pathology?

Nari

[EricM]

Is a cut finger a pathology?

I'd say no. If CRPS ensued though??? The cut finger is still not pathological, but something has become so.

On the other hand. Is the disease process which manifests as CRPS (for example) adaptive for some pathology?

[BB]

Hi Nari,

Anormal seems to run into the same problem as it requires a knowledge of normal for comparison, as you said.

Perhaps Abby Normal, though?

Yes, I would think the cut finger would demonstrate pathology as we've described it. A pathology of tissue continuity. The cascade of events that normally follow would not be though.

[nari]

Cory,

Very funny

I figured it might describe Eric's suggestion of the third category: that of pseudopathology.

If a cut finger is regarded as pathology, it is a sort of potential pathology; ie it may result in a disease process such as septicaemia or tetanus, or it may not. Most people would regard a cut finger as within the normal turn of events, unless they were terrified of blood or had haemophilia. But the variants within that normal range are large - almost as bad as LBP.

This definition conundrum also brings up the recent eagerness by the docs to call persistent pain a 'disease'. It may cheer up some of the patients, but does nothing to balance out the facts as we know them, so far.

Nari

[Bas Asselbergs]

Very interesting exchange. Nice to see Feldman again, Cory.
I can't help but gravitate back towards the issue of necessicity of terminology: what value does the "labeling" of the various findings really accomplish? I have found myself moving away as much as possible from labeling conditions with normal, pathological, abnormal etc. etc. Because the term "normal" is so tenuous, and socially and culturally (even in medicine, pain, suffering) determined, it begins to mean less and less.
Are not ALL non-pathological (i.e. "non-disease") neural processes, "normal"? Is not the meniscal tear a "normal" occurance of tissue trauma, followed by a "normal" neurophysiological process?
I think I am trying to get to the point that in our western societies, we have a fictional image of a perfect human and function (perfect homeostasis), which usually means happy and healthy. This flies in the face of reality, which is that every body will be injured, will be sick, and will hurt at some point, and will learn and progress from that process....

Ot maybe I am just abnormal....

[Bas Asselbergs]

In this vein, I'd like to quote a quote from Barrett's "Suppose this was true" thread:

"The mapping disparity and its potential to cause trouble reminds me of something a philosopher once said: Pain is the result of plans thwarted and hopes dashed.

It seems to fit perfectly here."

It does here too.
It brings the perception and the related processes of the individual to the foreground - I think this applies to the way we view the human function as it presents to us in all its aspects - including disease, dysfunction, pathology. The terms we have been discussing here are all value-based, with inherent judgement of the value and function of a process.

?

[Luke Rickards]

Interesting Bas.

So, the problem is that we may consider things from the view of a normal 'state' or a normal 'process'; the complexity being that at each point in time during a process there is also a state.

[Bas Asselbergs]

I think I see what you mean. I wonder if we need to label a state as related to a certain
process: neurophysiological adaptive process related to trauma, or neurophysiological adaptive process related to central (and/or peripheral) sensitisation, or even neurophysiological adaptive process related to disease X.
It focuses on the relationship between the process and its development and related matters, without a value qualification.

[bernard]

Maybe this picture will help to understand the problem?

[nari]

Bernard,

Exactly.

Nari

[Diane]

Maintaining a centroverted position with all of it might help us make sense in the moment. Just as we are part of a patient's context at any given moment, so are they part of ours. We need to be able to roll with the spectrum/sketch Bernard provided, and stay even keel with it.

I'm reminded of a book, old now, called Why We Get Sick:The New Science of Darwinian Medicine,
by Randolph M. Nesse and George C. Williams.

"Why, in a body of such exquisite design, are there a thousand flaws and frailties that make us vulnerable to disease?..."

I have this book but under a different (Brit) title that I can't recall off-hand (my copy came from achesandpainsonline when they sold other books alongside Topical Issues in Pain). Good book. Clears up a lot of the confusion about abnormal, normal, anormal etc.

[BB]

what value does the "labeling" of the various findings really accomplish?

Well, I guess my concern over the labeling as I've seen it in research and texts is that it implies something being wrong with the process, when the process is actually doing what it is built to do. I see it as similar to our patients being convinced there is something wrong with their tissues. This terminology may be perpetuating a sense that there isw something "wrong" with the physiology when, in fact, there is not.

As bernard's illustration shows, use of normal and abnormal in the literature is very problematic.

Pain is the result of plans thwarted and hopes dashed.

Agreed. I think that we often need to zoom all the way out to the level of culture and our interaction with our environment and the explanatory processes that guide that before we can actually identify something that can be labeled as "maladaptive" or dysfunctional.

[Line M]

Bernard's image reminded me of the bandwith of normal values, but I wonder how this does relate to the circular image of extreme sanity on one end almost matching extreme insanity on the other. That is my problem with statistic figures, when something works for 95% of the people, what about the other 5%. The only thing that counts is the one involved wherever in the whole range.

[bernard]

Line,

The "problem" is well known.
Every population fills a Gauss curve.
Every sample of this curve is a real person but often/ever a distinct individual.
In methods and protocols, extremities are discarded because it is retained a centered average that is though as representative of the whole/large population.

The problem will not solved because Man searches for a common rule (that exists) but want definite and standard values for its application. It won't work because the rule functions only with individual values.

[Jon Newman]

Some thoughts on disease and normality from the Evolving Thoughts blog (John Wilkins)

[nari]

As Wilkins pointed out, and also the commentators on his blog, there is confusion between normality and abnormality, and also between 'fitness' as understood by the general public and evolutionary fitness.
If 'fitness' was defined more clearly, then we would have less problem with normality.
Indeed, carried on further, someone with an unfavourable genetic condition may die before reproducing; this is a distinct advantage in an evolutionary sense. It promotes fitness and in a way it is 'normal'; but culture labels it abnormal, because to an individual it is seen as a sad and tragic event. Indeed, it has been shown that many four-footed animals also regard it as sad, such as elephants.

Labeling should exclude a value judgement - but that gets into very murky waters.

Nari

[Jon Newman]

Leroy Sievers asks a question along these lines today. Is this my new normal?

[EricM]

The topic of this thread has been tormenting me again lately. A conceptual model has been slowly forming in my mind and I’d like to test it out here in written form. I’d love to make it visual somehow but that will require several hours’ experimentation with Word.

Several different terms have been used in a variety of ways and it will take someone smarter than me to summarize what’s been written so far. So I’m going to define the terms as I see them with respect to my model. I’d like to zoom in to the level of an individual neuron. Over the course of its existence, a neuron will undergo a series of adaptive changes that presumably serve to enhance its survival and function and that of the whole organism. The changes may imply an increase or decrease in the likelihood of the nerve reaching action potential.

Over the last year, my work with chronic pain has introduced me to a variety of neuropathic conditions. In these cases, I now see that changes have occurred in the neuron that are maladaptive; they serve no purpose in the survival or function of the organism. Maladaptive changes may also cause an increase or decrease in the likelihood of the nerve reaching action potential.

I see no reason why both adaptive and maladaptive changes might not occur simultaneously within the same neuron, and presumably one system may influence the other though that may be speculation. The summation of these effects will set the overall level of excitability of that neuron. I think that this is largely a dynamic process in a constant state of flux.

It stands to reason that adaptive changes that may have increased the excitability of a nerve for a given period of time may reverse resulting in a reduced excitability. I have assumed that neuropathic, or maladaptive changes usually result in an increase in excitability, however I suppose it’s possible for it to go the other way. In general, it would seem that the more aggressive the maladaptive changes, the more excitable the neuron becomes.

(I have also generally assumed that it’s the presence of a signal arriving in a brain that may or may not be evaluated as threatening and consequently resulting in a pain experience. Can the reduction or absence of a signal also be perceived as threatening? )

It’s possible that this is blatantly obvious to many readers however it’s something I’ve had to struggle to understand. As a therapist it seems important to have an appreciation for the interplay between these influences to understand the effects and potential of our care.
In my observation, we can readily influence adaptive changes, however, we are less likely to influence maladaptive ones. For instance, in those with mechanical sensitivity overlaid on a neuropathic condition, I feel I’m frequently able to reduce the mechanical sensitivity, (the adaptive changes) but not the neuropathicness of the problem.

Any thoughts?

[BB]

Hi Eric,

I now see that changes have occurred in the neuron that are maladaptive; they serve no purpose in the survival or function of the organism.

I think it may be difficult to call a specific change at the neuron level as exclusively adaptive or maladaptive. That would be dependent upon the impact on the behavior and survival of the whole organism. For example, hypersensitivity may at times be adaptive for the organism (protective mechanisms) and maladaptive at other times (chronic pain) in terms of survival.

To me, when speaking at the level of the neuron, it makes most sense to call the change as physiological or pathological. Those changes in excitability or reduction of ABILITY to polarize would be pathological. Perhaps AIGS fall into this category in the opposite direction? I would think that any hypo or hyperexcitability in terms of change in threshold would be physiological.

In terms of adaptive and maladaptive, would it make more sense to consider phrasing such as "the organism is driving physiologic changes maladaptively?" I would then agree that the more maladaptively driven the physiologic processes are, the less likely we are to have success.

Given what I've said, now we just have to determine what determines maladaptivity!

[Diane]

we just have to determine what determines maladaptivity!

It may all just boil down to some maladaptive synaptic protein (s) that stop(s) being properly expressed. Apparently in the "transition zone" betwen PNS and CNS, the Schwann cells and the oligodendrocytes overlap for a little way. Maybe they don't always get along. Just a wild guess.

[Gary]

The only thing constant in life is change. One's ability to adapt to these changes is directly connected to their happiness, function, and perhaps even their maintenance of homeostasis.

The challenge for healthcare professionals is to recognize when the adaptations being made by patients are promoting or detrimentally affecting the goals (physical / functional /emotional) that they wish to achieve in their lives. Then use our expertise and physiological knowledge to help them to achieve their goals knowing that our treatment may have to be individually tailored according to each patient's need.

Does labeling have a place in this ? Maybe, Maybe not.

[BB]

Gary,

While I agree that labeling or categorizing of our patients usually suits our needs more than theirs, I think that this issue as it is applied to research/educational terminology in description of physiological processes is vital. And, that is how this whole conversation got started.

Also, if we can find some language that accurately reflects what is going on under our hands we'll have something quite useful. For example, we can discuss what means of current testing are actually measuring pathology? Does reflex testing do this?

[John W]

Piaget, the child psychologist and pioneering theorist on child development, described a process of adaptation in the cognitive development of child that may be useful here when we talk about what maladaptive means. The process starts with assimilation, whereby the child utilizes their senses to gather information about an object, followed by accommodation, which includes a process of discrimination so that the child determines the difference between objects, e.g. the difference between a nipple and a rattle, and then the response to the object is, or should be in a "normally" developing child, adapted to appropriately match the purpose of the object, i.e. suck on the nipple to get food, shake the rattle to hear sound. He used the term "schema" to describe the eventual result of successful cognitive adaptation of a child to any particular object within a particular environment. Ultimately successful adaptation boils down to the ability to function productively in one's environment. I don't think he would have considered merely the ability to survive as productive, but rather the ability to thrive.

Piaget's theory included detailed stages of child development that described a range of "normal" for the cognitive development of a child. However, he, himself, struggled with the boundaries of these stages until his death in 1980. So, the struggle with using labels is not particular to physical therapy. However, our close relationship with our colleagues in medicine has us often trying to fit our patients into tidy little boxes. Actually, I think PT is more like psychology than medicine, but that's another thread.

If we break down the process of assimilation, accommodation and adaptation into its physiological components, we may attach the PNS to assimilation followed by higher levels of the CNS to accomodation, and finally the ongoing interplay between PNS and CNS resulting in adaptation. Maladaptation could be ascribed to any interference at any level in the system that prevents adaptation, and eventually the failure of the individual to develop a useful and appropriate schema that allows them to thrive within their environment, society, culture.

Therefore, pain only becomes maladaptive when the individual decides that they can no longer thrive due to it. It's hard to tell sometimes whether certain patients have consciously, subconsciously or unconsciously made this decision, however. And therein lies the rub.

[Bas Asselbergs]

Good post John. That is indeed an interesting take.
I have a bit of trouble with the language of the final paragraph: it appears that you state that the individual decides that their pain is no longer useful to them. Is that indeed what you mean?

And "pain becomes maladaptive". Do you mean this? The maladaptation of the system becomes the driver of the pain experience.

I am trying to understand the meaning of your conclusions.

[John W]

Hi Bas,
I'm not sure about my conclusion either, so let's try a sports analogy in honor of Tiger Woods' victory last week in the US Open.

Obviously, Tiger had made a decision to participate in the tournament despite significant knee pain related to extensive pathoanatomy (torn ACL, meniscus and recent arthroscopy) and the demands of the golf swing. However, despite the pain, Tiger was not only able to compete at the highest level, but was able to win a major golf tournament. He decided he could thrive despite the pain; therefore, no maladaptive threat from the pain was present.

Or was it? In an interview after the tournament, Tiger said that he was going to "shut it down for a while" indicating that he was concerned about his knee, and we later found out that he had been playing with knee pain since a jogging injury last year. Did Tiger's decision to play in the US Open result in permanent damage to his knee that will negatively impact the course of his career? Was his decision to "ignore" the pain so he could play in this tournament a "maladaptive" cognitive response to significant somatic injury?

I'd argue that there's often no way to tell if the decision to forge on despite pain is a maladaptive or adaptive response until after the fact, and sometimes long after the fact, if then. In contrast, it's often easy to tell when the decision not to forge on-to move- despite pain is maladaptive. Frequently these are patients with cognitive noise (poor coping, low self-efficacy, depression, fear-avoidance, motivational dissonance) that have made a decision on some level that the pain will not allow them to thrive. In these cases your characterization of the maladaptation of the system driving the pain experience is accurate.

[Jon Newman]

Thanks for posts everyone. Very interesting.

For more on assimilation and accommodation, see here. It should be noted that at this level of analysis we obviously aren't considering Eric's issues with neuronal level changes.

The term "adaptation" might require some closer consideration also. A check at Wikipedia makes me wonder whether we shouldn't be considering acclimatization rather adaptation. I think this level of analysis would be relevant to and inclusive of changes observed at the level of the neuron.

[Bas Asselbergs]

Hello john. Yes, Tiger. He was told beforehand by the surgeon that playing would be putting his season at risk. He chose to continue. He chose to ignore his pain as much as possible.

Was his decision to "ignore" the pain so he could play in this tournament a "maladaptive" cognitive response to significant somatic injury?

I'd say that would be MY take. it is very obvious in this case that the brain and the mind and the personal issues play a HUGE role in how the pain is "valued".

It is for me a case of "normal" neural adaptation (limping, soreness, "stop-now-stupid") to injury, followed and overruled by a cognitive dysfunction: thus leading to further pathology and subsequent normal neural adaptation - a clear signal to stop playing (for more surgery and off for the year).

[BB]

Ultimately successful adaptation boils down to the ability to function productively in one's environment.

John,

I've been thinking about your great posts for the past couple of days. When thinking in terms of productivity we must consider goals to determine productivity. It is possible to meet the goal of performing a function productively (winning the US open) without meeting the goal of reducing pain. Of course, Tiger wasn't trying to reduce his pain as he played, but if he was the 2 goals would for sure have contradicted eachother frequently. There is evidence in the PT literature supporting this notion as well that demonstrate difference in movement toward an object when the focus is on the object vs. the internal state while getting there.

If we think in terms of goal states with pain, I think it makes sense to consider productively functioning (if that is adaptive....makes sense to me) as movement towards resolution (which equates to reduction of threat). This is where Wall's 3 stages of resolution come in quite handy.

Therefore, pain only becomes maladaptive when the individual decides that they can no longer thrive due to it.

I think that this is true if we are speaking in terms of function. But, when are speaking in terms of pain as a category then I think this only describes the level of severity of the affective component of pain.

At least that's my take. What do you think?

[John W]

Cory,
I agree that objects need predicates within a context to make sense. You're right that Tiger's goal (object) to win (predicate) an important tournament (context) superseded his desire (object) to not hurt (predicate) and potentially threaten his career (context). Obviously, he succeeded in the former, but it's too soon to tell if that choice means he has sacrificed his career.

Though sometimes difficult to be the bearer of bad tidings, it's not a difficult thing to determine that athletes have choices that bring potential consequences. But, on the flip side, for the folks with all the cognitive dissonance that I described in my previous post, they often seem unwilling to make a choice. They choose not to decide (which according to Neil Peart of the band "Rush" is still a choice).

I think passivity and complacency are maladaptive behaviors that drive the pain experience, and can be very difficult as a therapist to help the patient overcome.

[BB]

This article from Luke belongs here.

It seems we are not the only ones who think about such things:

‘‘Dysfunctional pain”
(pain in the absence of a lesion to the nervous system,
no negative sensory signs, and in the absence of any
inflammation) is an interesting concept that we believe
deserves further consideration.

[Jon Newman]

Here's more food for thought but done with the panache of the folks from Radio Lab.

Diagnosis (about an hour)

[Jon Newman]

Carl Zimmer has a post featuring an old interview with the George Williams mentioned in post #29. You can listen to the interview here.