The document discusses several theories of pain from history including: the intensity theory, specificity theory, pattern theory, gate control theory, and biopsychosocial model of pain. The intensity theory proposes that pain results from excessive stimulation. The specificity theory suggests specialized pain receptors transmit signals to a pain center in the brain. The gate control theory proposes that large nerve fibers can inhibit pain transmission. The biopsychosocial model views pain as influenced by physical, psychological, and social factors.

1. THEORIES OF PAIN
SUBMITTED BY
Anmol Prashar
B.Sc. Nursing 4th year (Intern)
Roll no 6
Date : 28-08-2020

2. CONTENTS
 Introduction
 Intensive Theory (Erb,1874)
 Specificity Theory(Von Frey,1895)
 Strong’s Theory (Strong,1895)
 Pattern Theory
 Central Summation Theory (Livingstone,1943)
 The 4th Theory of Pain (Hardy,Wolf and Goodell,1940s)
 Sensory Interaction Theory (Noordenbos,1959)
 Gate Control Theory (Melzack and Wall,1965)
 Biophysical Model of Pain
 Significance in Nursing practice
 References

3. INTRODUCTION
As long as humans have experienced pain, they have given explanations for its
existence and sought soothing agents to dull or cease the painful
sensation.Physiotherapists are often confronted by patient's experiencing pain and
patient's expectations of being cured are very high. A physiotherapist's approach to
pain will often depend on their knowledge and their client's perception of pain and it's
causes. Several theoretical frameworks have been proposed to explain the
physiological basis of pain, although none yet completely accounts for all aspects of
pain perception. A number of theories have been postulated to describe mechanisms
underlying pain perception. These theories date back several centuries and even
millennia (Kenins 1988; Perl 2007; Rey 1995
 Pain is whatever the experiencing person says it is, existing whenever the
experiencing person says it does” (McCaffery, 1989)
 “Pain is an unpleasant sensory and emotional experience, associated with or
expressed in terms of actual or potential tissue damage” (IASP, 1989)

4. Different Theories of Pain
Intensive Theory (Erb,1874)
Specificity Theory(Von Frey,1895)
Strong’s Theory (Strong,1895)
Pattern Theory
Central Summation Theory (Livingstone,1943)
The 4th Theory of Pain (Hardy,Wolf and Goodell,1940s)
Sensory Interaction Theory (Noordenbos,1959)
Gate Control Theory (Melzack and Wall,1965)

5. Intensive Theory of Pain
 An Intensive (or Summation) Theory of Pain (now referred to as the Intensity
Theory) has been postulated at several different times throughout history.
 First, conceptualized in the fourth century BCE by Plato in his oeuvre Timaeus
(Plato 1998), the theory defines pain, not as a unique sensory experience but
rather, as an emotion that occurs when a stimulus is stronger than usual.
 This theory is based on Aristotle’s concept that pain resulted from excessive
stimulation of the sense of touch. Both stimulus intensity and central summation
are critical determinants of pain.
 It was implied that the summation occurred in the dorsal horn cells.Arthur
Goldscheider further advanced the Intensity Theory, based on an experiment
performed by Bernhard Naunyn in 1859 [cited in Dallenbach (1939)].

6.  These experiments showed that repeated tactile stimulation (below the
threshold for tactile perception) produced pain in patients with syphilis who
had degenerating dorsal columns. When this stimulus was presented to
patients 60–600 times/s, they rapidly developed what they described as
unbearable pain.
 Naunyn reproduced these results in a series of experiments with different
types of stimuli, including electrical stimuli. It was concluded that there must
be some form of summation that occurs for the sub-threshold stimuli to
become unbearably painful.

8. Specificity Theory of Pain
 Specificity theory is one of the first modern theories for pain. It holds that
specific pain receptors transmit signals to a “pain center” in the brain that
produces the perception of pain.
 Von Frey (1895) argued that the body has a separate sensory system for
perceiving pain—just as it does for hearing and vision.
 This theory considers pain as an independent sensation with specialised
peripheral sensory receptors [nociceptors], which respond to damage and
send signals through pathways (along nerve fibres) in the nervous system to
target centres in the brain.
 These brain centres process the signals to produce the experience of
pain. Thus, it is based on the assumption that the free nerve endings are pain
receptors and that the other three types of receptors are also specific to a
sensory experience

10. Descartes' pain pathway:
"Particles of heat" (A) activate a
spot of skin (B) attached by a fine
thread (cc) to a valve in the
brain (de) where this activity
opens the valve, allowing
the animal spirits to flow from
a cavity(F) into the muscles
causing them to flinch from the
stimulus, turn the head and eyes
toward the affected body part,
and move the hand and turn the
body protectively.

11. Strong’s Theory of Pain
 Strong investigated physical pain, particularly that felt through the skin. He isolated
pain from displeasure by focusing on cutaneous pain, where the infliction of pain
carried no immediate threat, and therefore the emotional response was removed.
 He proposed that pain was an experience based on both the noxious stimulus and the
psychic reaction or displeasure provoked by the sensation.
 Strong concluded that pain is the sensation: The first sensation was the experience of
heat and then came the sensation of pain. He claimed that in in earlier stages of
evolution sensations were merely modifications of the nervous system and it was only
after the development of the ego did these sensations become projected emotions
known as displeasure

12. Pattern Theory of Pain
 In an attempt to overhaul theories of somaesthesis (including pain), J. P. Nafe
postulated a “quantitative theory of feeling” (1929).
 This theory ignored findings of specialized nerve endings and many of the
observations supporting the specificity and/or intensive theories of pain.
 The theory stated that any somaesthetic sensation occurred by a specific and
particular pattern of neural firing and that the spatial and temporal profile of
firing of the peripheral nerves encoded the stimulus type and intensity.

13.  Goldschneider (1920) proposed that there is no separate system for
perceiving pain, and the receptors for pain are shared with other
senses, such as of touch. This theory considers that peripheral
sensory receptors, responding to touch, warmth and other non-
damaging as well as to damaging stimuli, give rise to non-painful or
painful experiences as a result of differences in the patterns [in time]
of the signals sent through the nervous system.
 Thus, according to this view, people feel pain when certain patterns
of neural activity occur, such as when appropriate types of activity
reach excessively high levels in the brain. These patterns occur only
with intense stimulation. Because strong and mild stimuli of the same
sense modality produce different patterns of neural activity, being hit
hard feels painful, but being caressed does not. It suggested that all
cutaneous qualities are produced by spatial and temporal patterns of
nerve impulses rather than by separate, modality specific
transmission routes.

15. Central Summation Theory
It proposed that the intense stimulation resulting from the nerve
and tissue damage activates fibers that project to internuncial
neuron pools within the spinal cord creating abnormal
reverberating circuits with self-activating neurons.
 Prolonged abnormal activity bombards cells in the spinal cord,
and information is projected to the brain for pain perception

16. The Fourth Theory of Pain
It stated that pain was composed of two components:
the perception of pain and the reaction one has
towards it.
The reaction was described as a complex
physiopsychological process involving cognition, past
experience, culture and various psychological factors
which influence pain perception.

17. Sensory Interaction Theory
It describes two systems involving transmission of pain:
fast and slow system. The later presumed to conduct
somatic and visceral afferents whereas the former was
considered to inhibit transmission of the small fibers

18. Gate Control Theory
 Melzack has proposed a theory of pain that has stimulated considerable interest
and debate and has certainly been a vast improvement on the early theories of
pain.
 According to his theory, pain stimulation is carried by small, slow fibers that enter
the dorsal horn of the spinal cord; then other cells transmit the impulses from the
spinal cord up to the brain. These fibers are called T-cells. The T-cells can be
located in a specific area of the spinal cord, known as the substantial gelatinosa.
These fibers can have an impact on the smaller fibers that carry the pain
stimulation. In some cases they can inhibit the communication of stimulation,
while in other cases they can allow stimulation to be communicated into the
central nervous system.

19.  For example, large fibers can prohibit the impulses from the small fibers
from ever communicating with the brain. In this way, the large fibers
create a hypothetical "gate" that can open or close the system to pain
stimulation.
 According to the theory, the gate can sometimes be overwhelmed by a
large number of small activated fibers. In other words, the greater the
level of pain stimulation, the less adequate the gate in blocking the
communication of this information.

21. There are 3 factors which influence the ‘opening and
closing’ of the gate :
The amount of activity in the pain fibers. Activity in these fibers tends
to open the gate. The stronger the noxious stimulation, the more
active the pain fibers.
The amount of activity in other peripheral fibers—that is, those fibers
that carry information about harmless stimuli or mild irritation, such
as touching, rubbing, or lightly scratching the skin. These are large-
diameter fibers called A-beta fibers. Activity in A-beta fibers tends to
close the gate, inhibiting the perception of pain when noxious
stimulation exists. This would explain why gently massaging or
applying heat to sore muscles decreases the pain.

22.  Messages that descend from the brain. Neurons in the brainstem and cortex
have efferent pathways to the spinal cord, and the impulses they send can
open or close the gate. The effects of some brain processes, such as those in
anxiety or excitement, probably have a general impact, opening or closing
the gate for all inputs from any areas of the body. But the impact of other
brain processes may be very specific, applying to only some inputs from
certain parts of the body. The idea that brain impulses influence the gating
mechanism helps to explain why people who are hypnotized or distracted by
competing environmental stimuli may not notice the pain of an injury.

23. In the top panel, the nonnociceptive, large-diameter
sensory fiber (orange) is more active than the
nociceptive small-diameter fiber (blue), therefore the
net input to the inhibitory interneuron (red) is net
positive. The inhibitory interneuron provides presynaptic
inhibition to both the nociceptive and nonnociceptive
neurons, reducing the excitation of the transmission
cells. In the bottom panel, an open "gate" (free-flowing
information from afferents to the transmission cells) is
pictured. This occurs when there is more activity in the
nociceptive small-diameter fibers (blue) than the
nonnociceptive large-diameter fibers (orange). In this
situation, the inhibitory interneuron is silenced, which
relieves inhibition of the transmission cells. This "open
gate" allows for transmission cells to be excited, and
thus pain to be sensed.

24. The benefit of this theory is that it provides a physiological basis for the
complex phenomenon of pain. It does this by investigating the complex
structure of the nervous system, which is comprised of the following two
major divisions:
 Central nervous system (the spinal cord and the brain)
 Peripheral nervous system (nerves outside of the brain and spinal cord,
including branching nerves in the torso and extremities, as well as nerves
in the lumbar spine region

26. Biopsychosocial Model of Pain
The Biopsychosocial Model states that pain is not simply a
neurophysiological phenomenon, but also involves social and
psychological factors. It says that factors like culture, family,
nociceptive stimuli and environment influence pain perception and
thus ultimately affect a person’s emotions, behaviors and cognition.

27. For example, the Sun Dance is a ritual performed by traditional groups of Native
Americans. In this ritual, cuts are made into the chest of a young man. Strips of
leather are slipped through the cuts, and poles are tied to the leather. This ritual
lasts for hours and undoubtedly generates large amounts of nociceptive signaling,
however the pain may not be perceived as noxious or even perceived at all. The
ritual is designed around overcoming and transcending the effects of pain, where
pain is either welcomed or simply not perceived

29. Significance in Nursing Practice
Pain is a feared but universal experience.
Early pain theories focused on locating neurological pain fibers.
However, when surgical interventions failed to control the pain,
other explanations were sought. The interplay between practice
and research has advanced our understanding and management
of pain. Current pain theories explain pain as a physical,
psychological and social experience. Nursing interventions that
are multidimensional will have a better chance at ameliorating a
patient's pain.

30. Reference
 https://en.wikipedia.org/wiki/History_of_pain_theory
 Barron, C. J., Klaber Moffett, J. A., & Potter, M. (2007). Patient expectations of physiotherapy:
Definitions, concepts, and theories. Physiotherapy Theory and Practice, 23(1), 37–46.
 Moayedi M, Davis KD. Theories of pain: from specificity to gate control. J Neurophysiol 2013;
109:5-12
 Massieh Moayedi, Karen D. Davis Journal of Neurophysiology Published 1 January 2013 Vol.
109 no. 1, 5-12 DOI:
 Temperature and Pain Theories of Pain Perception
 Strong, C. A. (1895). The psychology of pain. Psychological Review, 2(4), 329–347
 http://jn.physiology.org/content/109/1/5
 http://admedadvice.blogspot.in/2006/09/types-and-theories-of-pain-types-of.html
 Modern Ideas: The Gate Control Theory of Chronic PainfckLRBy William W. Deardorff, PhD,
ABPP