Are There any Objective Measures of Pain?

[Uncayimmy]

Does anyone know if there have been any studies attempting to quantify pain objectively or at least measure it less subjectively than asking people to rate their pain?

I've said before that when I was young I began training myself to deal with pain. I've had quite a bit of success in how well I can tolerate it, but I would not claim that I have ever actually reduced my pain. By tolerate I mean continuing to function and keep my wits about me. I also mean that I can to a degree quell the inevitable emotions of fear and panic and the sense of losing control. I've been through a lot of involuntary pain (including severe pain) as well as voluntary pain (dentistry without numbing). And, no, I don't enjoy pain. I think pain sucks.

But the skeptic in me wonders if my high tolerance is actually due to me not feeling the "same pain" as someone else feels. For example, when the dentist hits close to a nerve and I feel intense pain, do others feel the "same pain" with much less of a stimulus? When I slam my head and get a gash, do I feel "less pain" than someone else who does the same thing? Is that why I can just say, "****. Oh, well..." and go about the task at hand while others hop around in pain and want to clean the wound, ice the bump, and pop some Tylenol?

Facts and studies would be great, but theories, as always, are welcome.

 

[tesscaline]

Being someone who suffers from a chronic pain disorder, the subject is of interest to me personally.

From what I understand, while there have been attempts to quantify pain objectively, nothing conclusive has really been achieved. I do remember seeing blurbs on the news occasionally about some study or other making the attempt, but I don't recall the names of the studies, or if they were even concluded at the time.

From what my doctors have told me, they can objectively state whether or not a signal is being sent by nerves. They can objectively state whether or not that signal is received by the brain. But they cannot objectively state what intensity of pain that signal may or may not produce in any given person. They simply don't have a way to quantify that yet. The best they can do in that regard is to use a pain index chart to help the patient communicate what level of pain they think they are experiencing, in relation to other sorts of pain they have had. i.e. My doctors ask me to rate my pain on a scale of 0-10, where 0 is no pain at all, and 10 is verging on losing consciousness/crisis situation/ER trip sort of pain.

Personally, I have a high pain tolerance. Always have. Didn't even need an asprin for a broken arm. Didn't need the codeine they gave me when they pulled my wisdom teeth. Didn't require pain treatment for a dislocated shoulder either. But other people, those same injuries/traumas would have required days (or more) of at least mild pain killers, if not narcotic ones.

One's tolerance for pain can also vary based upon the location of that pain, the length of time that pain goes on, and how sharp or diffuse the pain is (i.e. is it localized, like being stabbed, or is it spread out, like being hit with a cast iron skillet?).

I would love for greater headway to be made in understanding how the human body processes pain. I would also love to be able to quantify it objectively. I'm not sure though that we (humans) know enough about how the human CNS and brain work to be able to do those things just yet -- at least, not without performing unethical experiments on live test subjects...

 

[Uncayimmy]

Our experiences are similar. I, too, have issues with chronic pain. Just as another example, I was walking along the sidewalk the other day and slammed my forehead into a broken tree branch. It was a small, sharp branch. It hurt pretty bad, but my initial reaction was just "******" I walked the rest of the way with blood and sweat rolling down my face. I cleaned it up as best I could and put some antibiotic on it.

During the following week my wife commented that it didn't seem to be healing well. It was over my bad eye (hit with a piece of glass years ago), so I couldn't really see it all that well (that's also why I didn't see the branch). It hurt all the time, but not much. It was quite sensitive to the touch. It also felt hard, but I figured that was scab and scar tissue because it felt like a pretty deep cut.

Last night my wife took a look at it again, then pushed on it because it looked infected, Sure enough, some pus came out. Yeh, it hurt. Whatever, was my response. I went to look at it in the mirror and saw a small, black scab at one end. I tried picking at it, but it wouldn't come off. So I decided to pull it straight off by pinching it with my fingernails and yanking.

Lo and behold out came a splinter about 1.5cm long and about as thick as a round toothpick. As soon as it came out, there was a sense of relief in the wound. It stopped hurting right away. I can't believe I'd been walking around for a week with this in my head.

My wife asked me again, "didn't it hurt?" Yeh, it hurt constantly, but compared to being in such pain that you're puking, unable to stand or near passing out, it was nothing.

That's what really got me thinking about pain enough to actually post a question about it today. I find it fascinating.

 

[JJM 777]

Does anyone know if there have been any studies attempting to quantify pain objectively or at least measure it less subjectively than asking people to rate their pain?

Yes, anyone working in childbirth business will know that there have been endlessly studies about pain and its relievance, especially focusing on mothers giving birth. Without objective results, and without satisfactory such relieving methods, which would be safe and leave the mother conscious.

 

[Prometheus]

Have you seen this?

 

[Uncayimmy]

Yes, anyone working in childbirth business will know that there have been endlessly studies about pain and its relievance, especially focusing on mothers giving birth. Without objective results, and without satisfactory such relieving methods, which would be safe and leave the mother conscious.

How is that an objective measure of pain?

 

[Old man]

Lo and behold out came a splinter about 1.5cm long and about as thick as a round toothpick. As soon as it came out, there was a sense of relief in the wound. It stopped hurting right away. I can't believe I'd been walking around for a week with this in my head.

My wife asked me again, "didn't it hurt?" Yeh, it hurt constantly, but compared to being in such pain that you're puking, unable to stand or near passing out, it was nothing.

Yea, I had a run in with a thorn apple tree about 20 years ago. Long story, but to cut to the chase, after about a week I removed a 2.5 cm thorn from my left bicep that the emergency dept. doc 'missed'. He'd given me a 'script for Tylenol 3 and told me to take time off from until it healed. Didn't fill it (didn't need it), and went back to work after one day off (and, at the time, my work was quite physical).

I almost never take pain killers. How would I know when the pain goes away?

ETA: I've got a lot of these stories.

 

[Jorghnassen]

You mean something like this?

There's more.

 

[nimzov]

Dogs are very though and in general animals seem to feel less pain than we do.

Maybe it is it because they do not have the psychological factor associated with pain.

nimzo

 

[Fishstick]

You mean something like this?

There's more.

None of those are very objective as they rely on self-reports and behavioural tics.

 

[Jorghnassen]

None of those are very objective as they rely on self-reports and behavioural tics.

Well, it's hard to not rely on self-reports, besides, in most useful contexts that's pretty much the only way to assess it. I doubt there are studies on pain threshold that compare the actual sensory input to the reported perception. I'm not sure what kind of study could get past an ethics board...

 

[billydkid]

Yea, I had a run in with a thorn apple tree about 20 years ago. Long story, but to cut to the chase, after about a week I removed a 2.5 cm thorn from my left bicep that the emergency dept. doc 'missed'. He'd given me a 'script for Tylenol 3 and told me to take time off from until it healed. Didn't fill it (didn't need it), and went back to work after one day off (and, at the time, my work was quite physical).

I almost never take pain killers. How would I know when the pain goes away?

ETA: I've got a lot of these stories.

I thought I was the only old man from upstate New York!!! Most of you have heard my sad stories - and don't so many of us have them??? - but pain has been a central theme in my life for the past ten years of so. I have extensive experience in that department, having undergone a posterior C1/C2 fusion and having been left with severe, chronic headaches ever since. It is what my life is about and I hate it. I have a fairly high tolerance for pain in general, but there is something about the nature of headaches when they are truly severe that is singular compared to some other types of pain. When the pain is in your head, the pain IS you. So I live in constant apprehension waiting for the next uncontrollable attack. At times they are truly terrifying. At times I have been close to edge. It is impossible for someone who has not experienced this kind of pain to appreciate it. I know it was for me before. I don't know how many times I have longed to give my pain to dismissive doctors or self righteous bureaucrats who have appointed themselves the arbiters of what sort of pain relief people like myself should have access too, just for a week or a month so, so they can know how it feels to be truly helpless. Yes, this is a bitter subject for me and I am far from alone. I truly wish there were some way to objectively measure and quantitate pain. Until there is, pain sufferers will be at the mercy of those gatekeepers who feel better able to evaluate your suffering than you, yourself are.

 

[Uncayimmy]

Well, it's hard to not rely on self-reports, besides, in most useful contexts that's pretty much the only way to assess it. I doubt there are studies on pain threshold that compare the actual sensory input to the reported perception. I'm not sure what kind of study could get past an ethics board...

Self-reporting is definitely the most convenient way to assess pain, but it's still subjective. All of the scales have inherent problems. One obvious problem is when someone has never experienced "unbearable" pain before. By that I mean if the worst pain you've experienced is a bad cut or hitting your thumb with a hammer, how are you going to rate "unbearable" compared to someone who has been burned severely or someone who has had a nerve struck with a dental drill without numbing?

I'm not sure I understand why you say that studies couldn't get past an ethics board. Every time someone undergoes surgery, the doctors are inflicting pain. I'm no expert in this field or even a educated layman, but it seems to me this would provide an opportunity track pain signals without the person consciously suffering pain.

Of course, being aware of the pain is a major component of how we react. I know that I deal with pain better if I get a chance to "get ahead of it" as I like to say. By that I mean if pain comes on suddenly and unexpectedly, it's harder to deal with whereas when I am prepared for the pain, I can deal with. But as someone else said, sometimes the anticipation of pain can make it even worse.

Along those same lines sometimes the duration of the pain makes a big difference. A brief migraine is much easier to tolerate than one that lasts for hours or even a day. I know when I have periods of chronic recurring pain, I get "tired" of it. After a while it becomes harder to "bear' even though "objectively" I cannot say that the pain today is any "worse" than it was three weeks ago. The only difference today is that I am mentally/emotionally fatigued from dealing with it.

I would (possibly incorrectly) call that pain related stress. So maybe in a sense there are two things to look at: the pain impulses and the stress response.

 

[Jorghnassen]

Self-reporting is definitely the most convenient way to assess pain, but it's still subjective. All of the scales have inherent problems. One obvious problem is when someone has never experienced "unbearable" pain before. By that I mean if the worst pain you've experienced is a bad cut or hitting your thumb with a hammer, how are you going to rate "unbearable" compared to someone who has been burned severely or someone who has had a nerve struck with a dental drill without numbing?

That's just another issue with trying to "objectively" measure pain. It's hard, probably impossible, to define a universal scale that is independent of individuals and context.

I'm not sure I understand why you say that studies couldn't get past an ethics board. Every time someone undergoes surgery, the doctors are inflicting pain. I'm no expert in this field or even a educated layman, but it seems to me this would provide an opportunity track pain signals without the person consciously suffering pain.

Uh, no. The whole purpose of anesthesia is to prevent inflicting pain (well, it's more complex than that). The body under anesthesia does not react the same as a concious one. So whatever you'd measure would not be equivalent to the no anesthesia case.

Along those same lines sometimes the duration of the pain makes a big difference. A brief migraine is much easier to tolerate than one that lasts for hours or even a day. I know when I have periods of chronic recurring pain, I get "tired" of it. After a while it becomes harder to "bear' even though "objectively" I cannot say that the pain today is any "worse" than it was three weeks ago. The only difference today is that I am mentally/emotionally fatigued from dealing with it.

I would (possibly incorrectly) call that pain related stress. So maybe in a sense there are two things to look at: the pain impulses and the stress response.

It boils down to the fact that pain is not merely physical, there's a psychological aspect that makes it that much more intractable to objectively quantify. Igoring or attempting to remove that aspect is to further push the model from reality.

 

[tesscaline]

After combing around the net a bit, I've finally found reference to one of the studies I'd heard mentioned on the news. It's not the study itself (I can't seem to find that), but it does at least talk about it.

http://www.healthcentral.com/chronic-pain/c/5949/75928/researchers

Using fMRI to map the brain's pain responses, and even measure intensity. Not that fMRI is a practical way to measure pain, at this point in time anyway, but it's at least closer to an objective measure than using a self-reporting tool.

 

[tesscaline]

That's just another issue with trying to "objectively" measure pain. It's hard, probably impossible, to define a universal scale that is independent of individuals and context.

Hard, yes. Impossible, no.

Uh, no. The whole purpose of anesthesia is to prevent inflicting pain (well, it's more complex than that). The body under anesthesia does not react the same as a concious one. So whatever you'd measure would not be equivalent to the no anesthesia case.

And yet, there are forms of sedation (used in dentistry, for example) that don't actually render the patient unconscious. My significant other has, instead of "laughing gas", been given a pill that effectively causes amnesia of the dental procedure.

It boils down to the fact that pain is not merely physical, there's a psychological aspect that makes it that much more intractable to objectively quantify. Igoring or attempting to remove that aspect is to further push the model from reality.

I don't see that anyone is necessarily trying to remove or ignore that aspect. However, for a good scientific protocol, mitigating confounding variables is rather necessary. If that means finding a way to study solely the physical pain responses without the psychological responses clouding things, I don't necessarily see that as being a bad thing to at least start with.

Nor do I think it's unreasonable to look at trying to find an objective measure for pain. I would love for there to be a way to prove to people (even to some of my doctors) that I am not lying, exaggerating, or imagining the pain I suffer every single day. I think that having a tool that could prove the amount of pain a person suffers would be a good thing, both for people who really are suffering pain, and in dealing with people who don't actually have pain, but are instead just addicted to the narcotics typically prescribed for pain. I think it would also be an infinitely valuable tool in researching new drugs and other methods of pain relief.

 

[Uncayimmy]

Uh, no. The whole purpose of anesthesia is to prevent inflicting pain (well, it's more complex than that). The body under anesthesia does not react the same as a concious one. So whatever you'd measure would not be equivalent to the no anesthesia case.

Can you provide more evidence than just an assertion? I know that local anesthetics block the pain signals from being transmitted from the source to the brain. General anesthesia from what I can understand blocks the brain from responding to those signals. I don't know whether those signals are being sent or not. If, for example, my abdomen is sending signal that it's being sliced open, conceivably one could measure that signal before it reaches the brain.

What about medically induced comas? Are they giving analgesics to patients like they do with general anesthesia? Then we have coma patients, where there is some debate over how much pain they feel. Those in a persistive vegetative state are thought not to feel pain at all.

You still haven't answered my larger question: What are the ethical issues in trying to measure pain objectively? We already measure it subjectively, so what is unethical about hooking up a widget to measure <whatever it is> at the same time? We would then see if there is a correlation between <whatever> and that patient's subjective reporting as well as the aggregate reporting.

It boils down to the fact that pain is not merely physical, there's a psychological aspect that makes it that much more intractable to objectively quantify. Igoring or attempting to remove that aspect is to further push the model from reality.

What it all boils down to a series of chemical reactions. We measure anxiety levels subjectively, so why not also attempt to measure it objectively as well? I don't see why you want to stifle further research.

 

[Uncayimmy]

Nor do I think it's unreasonable to look at trying to find an objective measure for pain. I would love for there to be a way to prove to people (even to some of my doctors) that I am not lying, exaggerating, or imagining the pain I suffer every single day. I think that having a tool that could prove the amount of pain a person suffers would be a good thing, both for people who really are suffering pain, and in dealing with people who don't actually have pain, but are instead just addicted to the narcotics typically prescribed for pain. I think it would also be an infinitely valuable tool in researching new drugs and other methods of pain relief.

I recently switched primary care physicians. It can be a pain in the ass dealing with a doctor who is not convinced of your pain.

 

[Pup]

This is an interesting question. To offer another anecdotal datapoint, it's my perception that I tolerate pain poorly, but I feel pain less than average. In other words, I hate pain, I try to avoid it, I'm a wimp if some medical procedure is going to hurt, but in more than a few cases, people will ask, "Doesn't that hurt?" and my honest answer will be, "no" (mentally adding, "because if it did, you'd hear about it.")

So on a subjective pain scale, it looks as if I have a high tolerance for pain. But my guess would be that on an objective scale, my pain would actually register quite low, and therefore my tolerance wouldn't be high at all.

In that sense, I'm lucky, because society generally approves of people with a high tolerance for pain. But if those two variables are in fact separate, then people who are the opposite would be especially unlucky, because they'd seem like whiners or complainers. As several posters have noted, an objective way to measure pain would be extremely useful to prove that they were actually reacting reasonably to an unexpectedly higher level of objective pain.

 

[tesscaline]

I recently switched primary care physicians. It can be a pain in the ass dealing with a doctor who is not convinced of your pain.

I actually recently switched doctors (partially because I've moved to a different state) myself. My original doctors were not only not convinced of, but were actively denying care for, my pain -- I practically had to pry treatment out of them with a crowbar. My current doctors have been much more accepting and willing to work with me, which has been a nice change, even going so far as to explore new ideas about what might be the root of the problem so as to better provide treatment, as well as getting me into the care of a pain management specialist (something my previous doctors refused to even consider).