This power point outlines the various methods which have been used to measure chronic pain, and points out the various flaws with most of these, and the lack of value diagnostically

1. Measuring Pain
Lecture 17
Nelson Hendler, MD, MS,
Former Assistant Professor of Neurosurgery
Johns Hopkins University School of Medicine
Past president-American Academy of Pain
Management

2. Measuring Pain-Can It Be Done?
• Pain is a subjective experience
• Depression is a subjective experience
• Anxiety is a subjective experience
• Happiness is a subjective experience
• So how is it possible to measure a subjective
experience?
• Measure by subjective self reporting
• Measure by associated symptoms which are
quantifiable, i.e hours out of bed, or hours of
sleep, or weight gain or weight loss, or income

3. Variables in Measuring Pain
• Pain is a subjective experience that can be
perceived directly only by the sufferer.
• Pain is a multidimensional phenomenon that
can be described by pain location, intensity,
temporal aspects, quality, impact and meaning.
• Pain does not occur in isolation but in a specific
human being in psycho-social, economic, and
cultural contexts that influence the meaning,
experience and verbal and non-verbal
expression of pain.
• (National Institutes of Health 1987 p36)

4. Variables in Measuring Pain
• Ethnicity-Cultural-where the expression of pain is
either encouraged or stoic. Harold Merskey, MD
• Psychological state of the individual means feelings
which change over time. The best test to measure
this is the SCL-90, which asks how a patients feels
over the past 5 or 7 days, and how they feel pain
• Psychological traits of the individual means
character traits which are fixed and do not change
over time, such as obsessive compulsive
characteristics, supposedly related to feeling pain
• Genetics-levels of enkephalin and endorphins
determine “pain threshold.”

5. Visual Analogue Scale
Incredibly, this is the Food and Drug Administration (FDA) accepted method of
determining the efficacy of a pain relieving medication. The patient is asked to
rate his pain, on a 100 mm long line, before receiving the medication, and then
the patient takes the medication. After the medicine begins to work, the patient
answers how much pain he has, by marking another 100 mm line. The
researcher measures how many “mm of pain” the patient had before and after
the medication, to determine the effectiveness.

6. McGill-Melzack
• Ron Melzack from McGill, and Warren Torgeson
at Johns Hopkins, recognized that patients used
different words to describe their pain.
• Dr. Melzack rank ordered 30 words used to
describe the severity of pain, from mild, to
nagging to sharp, severe, and excruciating.
• This scale is used to measure the severity of
pain….and theoretically measure improvement or
worsening over time.
• Melzack failed to recognize that different types of
pain fibers have specific types of pain associated
with them, i.e. C fibers have sharp pain, etc.

7. Rat Hot-Plate Test
• Pharmaceutical companies measure the efficacy
of early stage pharmaceuticals by the following
methods:
• They inject a mouse with a medication, and
place the mouse on a hot-plate.
• If the mouse jumps, the interpretation is that
the drug has no analgesic properties.
• If the mouse doesn’t jump, they interpret this as
the drug is an analgesic, but don’t necessarily
consider that the drug may be a sleep inducing
drug, paralytic, or ionic flux drug

8. Petrovich Pain Apperception Test
A patients is shown a series of 17 cards, and has to rank order which pain
hurts more, by putting the cards in ascending order. From this sequencing,
the physician is theoretically able to determine the pain threshold of the
patient, and ability to tolerate pain. The question becomes—to what end?
Would you rank the card on the left as hurting more than the card on the
right, or the other way around?

9. 5th vital sign
• James Campbell, MD past president of the
American Pain Society, felt pain was under-
treated, and want medical staff to be aware of
the severity of pain in their patients.
• So he implemented asking patients how much
pain they had on a scale of 1-5, and
considered this the “5th vital sign” along with
pulse, blood pressure, weight and height
• Dr Campbell was able to get the “5th vital sign”
accepted as a “standard of care” for medical
practices and hospital care.

10. Smiley Face
“Smiley Face” is typically used to measure pain in children or semi-literate patients

11. Ascending and Descending Just
Noticeable Differences (JND)
• The Difference Threshold (or "Just Noticeable
Difference") is the minimum amount by which
stimulus intensity must be changed in order to
produce a noticeable variation in sensory
experience.
• Ernst Weber (pronouned vay-ber), a 19th
century experimental psychologist, observed
that the size of the difference threshold
appeared to be lawfully related to initial stimulus
magnitude. This relationship, known since as
Weber's Law.

12. Weber’s Law
• Weber’s Law can be expressed as:

13. Weber’s Law
• Weber's Law, more simply stated, says that the size of the just noticeable
difference (i.e., delta I) is a constant proportion of the original stimulus value. For
example: Suppose that you presented two spots of light each with an intensity of
100 units to an observer. Then you asked the observer to increase the intensity of
one of the spots until it was just noticeably brighter than the other. If the
brightness needed to yield the just noticeable difference was 110 then the
observer's difference threshold would be 10 units (i.e., delta I =110 - 100 = 10).
The Weber fraction equivalent for this difference threshold would be 0.1 (delta I/I
= 10/100 = 0.1). Using Weber's Law, one could now predict the size of the
observer's difference threshold for a light spot of any other intensity value (so long
as it was not extremely dim or extremely bright). That is, if the Weber fraction for
discriminating changes in stimulus brightness is a constant proportion equal to 0.1
then the size of the just noticeable difference for a spot having an intensity of 1000
would be 100 (i.e., delta I = 0.1 X 1000 = 100).
• Weber's Law can be applied to variety of sensory modalities (brightness, loudness,
mass, line length, pain, etc.). The size of the Weber fraction varies across
modalities but in most cases tends to be a constant within a specific task modality.

14. Von Frey Hairs
• A von Frey hair is a type of aesthesiometer designed in
1896 by Maximilian von Frey.
• These hairs are made from nylon filaments of varying
diameter. The hairs are to be pressed against the skin
with enough force so that the hair buckles and forms a
U-shape. Given that the force required for this is
assumed to be constant, these hairs can be used to
apply a very accurate force on specific areas of the skin,
thus making von Frey hairs a possible diagnostic,
research, and screening tool.
• von Frey hairs are readily used to study skin areas with
normal responsiveness, as well as hyper- or
hyposensitive areas.

15. A Von Frey Hair Tool Kit. This tells a physician the relative
pressure it takes to feel the hair, and then if the hair is
painful. The hair start at a small diameter and ascend to
larger ones.

16. Tourniquet Test- Sternbach
• A patient rates their chronic pain as a percent of
unbearable, i.e. “my pain is 50% of unbearable”
• A tourniquet is applied to the arm, and the
patient is asked to tell the doctor when the acute
pain in the arm equals the pain the patient
normally feels, and then tells the doctor when
the pain is unbearable, and the tourniquet has to
be removed.
• The doctor takes a ratio base on time before the
acute pain equals normal chronic pain over time
to maximum tolerance, and comparers it to the
original estimate. But acute doesn’t equal chonic

17. Tourniquet Test- Sternbach
• So if the patient originally ranked his pain as
50% of unbearable, but after 30 seconds of
tourniquet time said the pain from the
tourniquet equaled the pain he normally felt and
at 2 minutes (120 seconds) said the pain was
unbearable, then the doctor would calculate the
tested pain as 25% of unbearable, and accuse
the patient of exaggerating their pain, because
he reported it was 50% of unbearable, before
the “objective” tourniquet test, where it was
tested to be only 25% of unbearable. (see
Sternbach-Pain Patients-Traits and Treatment)

18. Using Psychological Tests to
Measure Pain
• Of all of the misapplications of psychological
tests, the MMPI (Minnesota Multiphasic
Personality Disorder) test has been the most
misapplied.
• Researchers claim they can measure the
severity of pain, or presence or absence of
pain, based on scores on the MMPI test,
which is a 566 question test, with true-false
answers, which measure personality traits.

19. MMPI of “low back losers”
• Pilling, Bleumer, and Sternback, based on their
misunderstanding of pain and the MMPI, labeled
patients “Pain prone patient,” “pain neurosis,” and
“low back loser.”
• They based this on the elevated scales of 1 and 3
(hysteria and hypochondriasis), of the MMPI, and
the absence of the elevation of scale 2 (depression).
• This formed the so called “Conversion V” because
the graph of the scales has a V in it.
• This is normal in early and late stage chronic pain,
but considered pathological by other authors

20. Example of graphic representation of MMPI scores. Hs is hysteria, D is
depression, Hy is hypochondriasis. If all three scales are elevated, and depression
is more elevated than Hs, and Hy, then Bleumer calls this a neurotic triad. Hendler
calls this a normal response to chronic pain, and Bleumer calls it “pain neurosis.”.

21. Lees-Haley “Fake Bad Scale” of MMPI
• This test has been thrown out of court a number
of times in Florida.
• The scale of the MMPI Lees-Haley put together
“diagnoses” plaintiffs as malingering 85% of the
time.
• These statistics are not supported by other
research, and in fact, are rejected by noted
MMPI authorities.
Sims, Dorothy C., “Cross Examining the Psychiatric Expert,” WILG (April 2005): 12-15.
Tortter v. Washington Group International, Inc, et al, Case No A466763, Deposition of Paul
Lees-Haley, Vol. 1, taken August 19, 2004
Sims, Dorothy C, The Myth of Malingering, Plaintiff Magazine, December, 2007,

22. Cold Tolerance Test-Ice Water Immersion
• This technique uses the same rationale as the
tourniquet test, but instead of “unbearable pain”
measured with a tourniquet, ice water is used.
• A patient rates their pain as a percent of
unbearable, i.e. my pain is 50% of unbearable
• The patient’s arm is plunged in ice water, and the
patient is asked to tell the doctor when the pain
in the arm equals the pain the patient normally
feels, and then tells the doctor when the pain is
unbearable, and the arm has to be removed
from the ice water.

23. Cold Tolerance Test-Ice Water Immersion
• The doctor takes a ratio base on time before pain
equal normal pain over time to maximum tolerance,
and comparers it to the original estimate.
• If the patient originally ranked his pain as 50% of
unbearable, but after 30 seconds in ice water said
the pain from the ice water equaled the pain he
normally felt and at 2 minutes (120 seconds) said the
pain was unbearable, then the doctor would
calculate the tested pain as 25% of unbearable, and
accuse the patient of exaggerating their pain,
because he reported it was 50% of unbearable,
before the “objective” ice water test, where it was
tested to be only 25% of unbearable.

24. Lamp Black on Forehead
• In the 1940s, a group of doctors at the University of
Cornell, led by Hardy, set out to create a unit of pain
intensity. Using the "dol" as a unit, the physicians created
a 21-point quantitative scale, from ½ to 10.5 “dols”
• Studies on Pain: A new method for measuring pain threshold
, researchers inflicted pain upon subjects using by applying
heat to their foreheads for three seconds at a time. 8 dols
left 2nd degree burns.
• The intensity of pain increased as researchers increased
the heat in each experiment.
• Discrimination of differences in intensity of a pain stimulus as
, with a single dol divided into two "just discernible
changes in pain".

25. Diagnostic Value of Measuring Pain
• The severity of pain had no diagnostic value
• Since there are so many variables contributing to
the perception of pain from the psychological
state of the individual, to the ethnicity, to the
biochemistry of the body, the severity of pain is
too inconsistent from one individual to another.
• However, the type of pain had diagnostic value. A
burning pain suggest neuralgia, and numbness
severe neuropathy. A constant pain suggests
compression, while an intermittent pain suggests
mechanical damage. A throbbing pain is vascular.

26. Research Value of Measuring Pain
• Pain relief is one way researchers quantify the
value of their treatment.
• There are many problems using pain relief as a
measure of success, since pain perception is so
highly variable.
• Relief measurement of a patient before and after
a treatment is more reliable than comparing
relief in a group of patients before and after a
treatment.
• The best measures are quantifiable indirect
measures, such as how much medicine is used.

27. Pain Validity Test from
www.MarylandClinicalDiagnostics.com
• The test does not ask about pain severity
• Records the impact of pain on the life of the patient
• The Pain Validity Test is the only test which has
been proven to have a predictive medical ability
• The Pain Validity Test can predict with 95%
accuracy which patient will have a moderate or
severe abnormality on at least one correct objective
medical test
• The Pain Validity Test can predict with 85%
accuracy which patient will not have abnormalities

28. Pain Validity Test
• Pain Validity Test is available on Internet, at
www.MarylandClinicalDiagnostics.com, to
validate pain, by predicting the presence or
absence of organic pathology.
• It allows a physician to improve diagnostic
accuracy, and serves as a screening tool to
help get an accurate diagnosis.
• There are 7 articles about the Pain Validity
Test, involving 794 patients.
• The test has 32 questions, and takes only 15
minutes to administer & results in 5 min.
• It is available in English and Spanish

29. Scattergram of Computer Scored Pain Validity Test.
On the left, 3* is a severe abnormality, 2 a moderate abnormality, 1 a mild abnormality,
and 0 is no abnormality on at least one objective medical test. At the bottom, 8-25
represent the score on the Pain Validity Test. 17 or less is an Objective Pain Patient, 21
point or higher is an Exaggerating Pain Patient
*3
65/69 = 95%
2 Exaggerating
Objective Pain Patient Pain Patient
1
11/13 = 85%
0
8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

30. Explanation of the PVT Scattergram
• Look at Scattergram- Objective Pain Patients have a 95%
chance of having moderate or severe abnormalities on
at least one correct objective measure of organic
pathology, such as EMG nerve conduction studies, root
blocks, facet block, provocative discograms, MRI, CT, etc.
• Medical articles prove that the MMPI has no predictive
medical capabilities. Insurance companies often claim
that the MMPI does, but can’t prove it.
• Pain Validity Test can identify patients who will not have
medical abnormalities with 85% accuracy.
• In a series of articles, it was reported that only 6%-13%
of patients are exaggerating
Available at www.MarylandClinicalDiagnostics.com

31. Summary
• There is little or no diagnostics value to trying
to measure the severity of pain
• Measurement of pain is useful for measuring
treatments and outcomes of treatment
• Indirectly measuring the impact of pain on a
person’s life is more objective than measuring
pain itself
• Knowing the type of pain, and what makes it
better or worse, has some diagnostic value
• Psychological traits have no predictive value
for the causes of pains