How Is Pain Measured?

[sophia8]

A woman on a list I'm on has just posted with a long tale of her current medical woes - she says she's been diagnosed with a ragbag of "mixed connective tissue disorders" including MS, Lupus, Scleraderma, Lou Gehrigs and possibly myositis; plus Achalasia (a swallowing disorder), plus a perforated colon, plus possible cancer of the liver.
Now, I do have a friend who is practically a walking medical encyclopedia of chronic illnesses; so although this woman's list sounds unlikely, I'll take her word for it (for now).
However, what makes my skeptic antenna twitch is her claim:

my pain levels run from 30 to 80 times what someone with terminal bone cancer endures.

She doesn't say how this pain was measured. So how do medics measure pain? Is it possible to measure pain other than subjectively?
I have arthritis and tendonitis, and when I need to describe the level of the pain to doctors, I'm simply asked to give a figure between 1 to 10 - nobody's ever suggested that there might be an objective way of measuring my pain.

 

[fls]

A woman on a list I'm on has just posted with a long tale of her current medical woes - she says she's been diagnosed with a ragbag of "mixed connective tissue disorders" including MS, Lupus, Scleraderma, Lou Gehrigs and possibly myositis; plus Achalasia (a swallowing disorder), plus a perforated colon, plus possible cancer of the liver.
Now, I do have a friend who is practically a walking medical encyclopedia of chronic illnesses; so although this woman's list sounds unlikely, I'll take her word for it (for now).
However, what makes my skeptic antenna twitch is her claim:
She doesn't say how this pain was measured. So how do medics measure pain? Is it possible to measure pain other than subjectively?
I have arthritis and tendonitis, and when I need to describe the level of the pain to doctors, I'm simply asked to give a figure between 1 to 10 - nobody's ever suggested that there might be an objective way of measuring my pain.

The claim with respect to pain is BS (the rest sounds like BS, too - more like a list of possible conditions to rule in/out). Pain is usually measured as you describe - on a subjective scale from 1 to 10. One could look at objective measures of the presence of pain, such as autonomic responses (eg. increased heart rate or blood pressure). But that doesn't translate to the level of pain which is subjective. And the scale is probably not linear (i.e. "4" is not twice as bad as "2"), making it difficult to compare numbers in the same person (let alone comparing numbers given by two different people).

Linda

 

[Darat]

Not got a quick answer for you but this site is an excellent jumping off point for researching about pain: http://www.jr2.ox.ac.uk/bandolier/booth/painpag/index2.html

 

[Marc L]

Like Linda pointed out, feeling pain is entirely subjective. Take me and another random guy with an identical physical makeup. Poke us both with a pin. We'll both feel pain, but the experience will be completely different. He may shrug it off, while I'll curl up in a little ball and start wailing for my mommy.

That's why hospitals now use the 1-10 method. What they're asking is "how does the pain feel to you." When I was living in Maryland, doing temp work at a hospital, there was a sign that read, "Remember, pain is what the patient says it is."

Marc

 

[Rasmus]

The basic measure of pain is an ouch.

One ouch hurts as much as 20 ow's, each of which is equivalent to twelve argh's.

If you are in severe pain, you might want to express the amount of pain in yow's. One yow is as painful as 21 ow's or 252 argh's.

 

[Alkatran]

Oh well, obviously, you apply an electrical current across the hand. We then define the "pain amperage" to be the amps required for the patient to stop complaining about the test pain and shift their attention to the pain from the current.

...

[EVIL LAUGH]

 

[sophia8]

Like Linda pointed out, feeling pain is entirely subjective.
Marc

That's what I thought, but I wondered if somebody has come up with some new technology.
I wouldn't know about the pain of cancer, but the worst pains I've experienced are tooth extraction without anaesthesia, and childbirth (the tooth extraction wins, but only just). I'd be unconscious - or very quickly dead - if I experienced anything like "30 to 50" times that.
So I'll take her other claims with a bucketful of salt as well.

 

[JJM]

A woman on a list I'm on has just posted with a long tale of her current medical woes - she says she's been diagnosed with a ragbag of "mixed connective tissue disorders" including MS, Lupus, Scleraderma, Lou Gehrigs and possibly myositis; plus Achalasia (a swallowing disorder), plus a perforated colon, plus possible cancer of the liver. ...

A person with a perforated colon is a few hours from dead. Problems solved.

 

[bpesta22]

Actually, the oldest branch of psychology-- psychophysics-- has an answer to the question.

There are two thresholds for any sensation: The limen, and the just noticable difference.

The limen is the absolute threshold (dimmest light that we can still see, or weakest tone we can still hear). In pain research, it would be the intensity of the stimulus (typically electric shock or heat) that first produces a pain sensation.

Once the limen is established, then the task is to scale perception by asking the question: By how much do we have to increase the intensity of the threshold stimulus for us to notice the difference (at X intensity, we report first seeing the light. How much do we have to increase X so that the subject percieves X + n to be brighter than X).

For pain research, a long time ago, people used a dolorimeter-- a device for inflicting various levels of pain on a person's skin. The researchers were the own subjects (go figure) and mapped out the scale of perception for painful stimuli!.

In general, though, a thing call weber's law applies:

If you start with a weak stimulus, then you just need to increase it a little bit to notice a difference.

But,

If you start with a strong stimulus, then it takes a much bigger change for us to notice the difference.

So, if two candles are burning in a dark room, and we light one more, the room will appear brighter.

If 100 candles are burning and we light one more, we won't notice an increase in brightness.

For just about anything we can sense, there's a weber fraction (derived from research) telling just how much you have to increase the intensity of the standard stimulus for a person to notice a difference.

The fraction for lifted weight is .022. So, a comparison weight has to be about .04 g heavier than a 2g standard weight for us to determine the difference.

But, if the standard weighed 200g, then the just noticable difference would occur for a comparison weight that's 4g heavier.

Smaller weber fractions mean more sensitivity.

The WF for electric shock is .013 (we're pretty damn sensitive to increases in pain!).

For pain in general, the WF is about 4%-- a 4% increase in the intensity of the pain stimulus is noticed as "hurting more".

(interesting side note, the researchers who figured this out started by inflicting pain on their foreheads, but then switched to arms as the blisters that resulted were easier to care for on the arm versus the head!)

The 1-10 scale used in hospitals would be highly unsophisticated compared to the psychophysical measures of pain.

 

[fls]

The 1-10 scale used in hospitals would be highly unsophisticated compared to the psychophysical measures of pain.

I'm not sure how this would help the OP since studies with dolorimeters confirm the subjective nature of pain (i.e. people report different levels of pain and differences in their ability to discriminate when exposed to the same stimuli). Similar devices are used to try and get an objective measure of pain in research involving musculoskeletal disease (maybe in other areas, I just can't think of any off-hand). From what I remember, it serves more as a comparison of before and after, rather than a way to compare two individuals. And the Visual Analogue Scale (a visual representation of the 1-10 scale) tends to correlate more strongly with outcomes than the devices do (or the results are equivalent).

I agree that the 1-10 scale is unsophisticated. But on the other hand, other unsophisticated scales have turned out to have higher predictive power than carefully quantisized scales (eg. self-evaluations of health status).

Linda

 

[bpesta22]

I'm not sure how this would help the OP since studies with dolorimeters confirm the subjective nature of pain (i.e. people report different levels of pain and differences in their ability to discriminate when exposed to the same stimuli). Similar devices are used to try and get an objective measure of pain in research involving musculoskeletal disease (maybe in other areas, I just can't think of any off-hand). From what I remember, it serves more as a comparison of before and after, rather than a way to compare two individuals. And the Visual Analogue Scale (a visual representation of the 1-10 scale) tends to correlate more strongly with outcomes than the devices do (or the results are equivalent).

I agree that the 1-10 scale is unsophisticated. But on the other hand, other unsophisticated scales have turned out to have higher predictive power than carefully quantisized scales (eg. self-evaluations of health status).

Linda

Good points-- I guess the problem I have with the 1 to 10 scale is it assumes a linear (interval?) relationship. 4 is twice as painful as two, etc.

The relationship between stimulus intensity and pain though is a power function with an exponent of 3.50.

 

[fls]

Good points-- I guess the problem I have with the 1 to 10 scale is it assumes a linear (interval?) relationship. 4 is twice as painful as two, etc.

Yeah, I pointed that out in my original post. It is hard to overcome the urge to apply arithmetic when faced with numbers. <grin>

Linda

 

[Schneibster]

There is actually a unit of pain- the "dol." It was defined during research into pain in the 1940s and 1950s as two "just noticeable differences" in the level of pain a subject was feeling. According to the Wiki article, it is not much used any more, but I thought it was worth mentioning.

A common test for pain tolerance is to ask a subject to stare at a blank area and keep from blinking as long as they can. 30 seconds is said to be average, one minute extremely high. Apparently a small amount of pain due to the cornea drying out is what stimulates us to blink.

 

[sophia8]

There is actually a unit of pain- the "dol." It was defined during research into pain in the 1940s and 1950s as two "just noticeable differences" in the level of pain a subject was feeling. According to the Wiki article, it is not much used any more, but I thought it was worth mentioning.

A common test for pain tolerance is to ask a subject to stare at a blank area and keep from blinking as long as they can. 30 seconds is said to be average, one minute extremely high. Apparently a small amount of pain due to the cornea drying out is what stimulates us to blink.

Hmm. My tendonitis can flash up to around 9 on my personal pain scale for up to a minute or so when I move the affected arm the wrong way. When that happens, I sometimes try to "zone out" the pain by staring hard at a blank wall - I don't think I ever blink during this time.
I certainly don't think I'm especially tolerant to pain.

 

[sophia8]

A person with a perforated colon is a few hours from dead. Problems solved.

This is the relevant part of her post (my bolding):

I also had a CT scan done to see what is going on with my liver and ovaries
because I had a hysterectomy at 26 and am showing signs of cancer...when
they read the ct scan, they called my gyn/oncologist (I have two gyns...a
general practice gyn and a gyn/onc) who was on maternity leave. Her nurse
called me and told me to get in touch with my primary care physician at
around 4 pm on Friday evening. I called and he got back to me first thing
Monday morning saying ???? I said, "Have you gotten your copy of my CT scan from W********* Radiology? The answer was no. so I called WRA and he called WRA and on TUESDAY, find out my colon has perforated and I should have had emergency surgery on Friday afternoon when the surgeons would have gone into my abdomen all guns ablazin...except, by the time my "little gastro" (I have two gastroenterologists... general practitioner gastro and an esophageal expert gastro) my primary care physician who is hopping mad, my brand spanky new surgeon have consulted with each other not to mention the odd call to my rheum, it is WEDNESDAY before I can do the follow-up ct scan. This is the first time in my life I have ever had a surgeon show up to shepherd me through doing a CT scan. Gotta love this man. My family doesn't even stand by me during these tests. So...something more than just achalasia is going on.

As far as I can gather, that took place last week. No further mention of surgery, and she was still posting to the list two days ago.

 

[Soapy Sam]

Hmm. My tendonitis can flash up to around 9 on my personal pain scale for up to a minute or so when I move the affected arm the wrong way. When that happens, I sometimes try to "zone out" the pain by staring hard at a blank wall - I don't think I ever blink during this time.
I certainly don't think I'm especially tolerant to pain.

That's interesting. I also have a 0-10 scale I came up with for my arthritis.
I've never been over 5 for more than a few seconds. It's sort of logarithmic.
At 7 I would probably chew my own head off.

 

[Schneibster]

It's the length of time that you can keep from blinking that's important- and a blank wall is chosen because staring at a bright light can affect the test. IIRC, the person doing the test is not considered reliable; it's possible to blink without noticing it. A third party should measure the time.

 

[Iamme]

A woman on a list I'm on has just posted with a long tale of her current medical woes - she says she's been diagnosed with a ragbag of "mixed connective tissue disorders" including MS, Lupus, Scleraderma, Lou Gehrigs and possibly myositis; plus Achalasia (a swallowing disorder), plus a perforated colon, plus possible cancer of the liver.
Now, I do have a friend who is practically a walking medical encyclopedia of chronic illnesses; so although this woman's list sounds unlikely, I'll take her word for it (for now).
However, what makes my skeptic antenna twitch is her claim:
She doesn't say how this pain was measured. So how do medics measure pain? Is it possible to measure pain other than subjectively?
I have arthritis and tendonitis, and when I need to describe the level of the pain to doctors, I'm simply asked to give a figure between 1 to 10 - nobody's ever suggested that there might be an objective way of measuring my pain.

Now this is really getting wierd. I just posted on the Pi thread that it was a coincidence the OP poster started that thread, as I was thinking of that this morning. Now get ready for this: I was also thinking about starting a thread here today. Yes, today, about pain. What I was going to pose is how can me measure it...to know that everyone feels the same pain when they say, "Oooh...that hurts." I am not kidding! I wanted to know how often football players with a major injury lay on their back and wait for help to come out on the field. Often times, with major tears (ruptures), they just lay there motionless. If that were me?...in that pain?..I would be wrything on the ground!

 

[Mercutio]

It's the length of time that you can keep from blinking that's important- and a blank wall is chosen because staring at a bright light can affect the test. IIRC, the person doing the test is not considered reliable; it's possible to blink without noticing it. A third party should measure the time.

Another standard pain stimulus used is a bucket of ice water. Submerge your arm in it up beyond the elbow and keep it there as long as possible.

Never seemed that painful to me, but I have had students who could not go half a minute.

 

[Jeff Corey]

You ever see football players train? We had the Giants training on campus about ten years ago. They train by running into these big padded skids as hard as they can. The college players do it too. They get used to it. And there's the "take it like a man" thing.
"Oh, Boomer broke his collarbone. Shake it off Boomer."