Transcript Pain - PSY411

Pain
Assist. Prof. Merve Topcu
PSY 411 Health Psychology
Department of Psychology Çankaya University
2016-2017, Fall
Pain in general
• Pain plays a necessary and basic role in survival
• Congenital insensitivity to pain
• Individuals are not able to feel pain
• Pain may exist for no clear reason
• Phantom limb pain
• People experience pain in parts of the body that do not exist
• Beliefs about pain changes the repsonse
Pain & the Nervous System
• Pain originates as stimulation to the skin and muscles
• Peripheral nervous system (PNS) is responsible
Organization of NS
CNS
Brain
Peripheral NS
Spinal
cord
Autonomic
NS
Sympathetic
NS
Parasympathetic NS
Somatic NS
Sensory &
Motor
nerves
(Skin &
muscles)
Cranial
nerves
(Head &
neck)
The Somatosensory System
• conveys sensory information from the body to the brain
• consists of several senses, including touch, light and deep pressure, cold,
warmth, tickling, movement, and body position
• 3 types of neurons
• Afferent (sensory) neurons relay information from the sense organs toward the brain.
• Efferent (motor) neurons result in the movement of muscles or the stimulation of
organs or glands
• Interneurons connect sensory to motor neurons
• The sense organs contain afferent neurons, called primary afferents
• receptors that convert physical energy into neural impulses
The Somatosensory System
• Nociception
• The process of perceiving pain
• Nociceptors
• receptors in the skin and organs responding to various types of stimulation that may cause tissue damage,
such as heat, cold, crushing, cutting, and burning
• Myelin
• A fatty substance that acts as insulation
• Myelinated afferent neurons, called A fibers, conduct neural impulses faster than unmyelinated C fibers do.
• The larger A-beta fibers and the smaller A-delta fibers are essential
• A-beta fibers conduct impulses more than 100 times faster than small, unmyelinated C fibers
• Stimulation of A-delta fibers produces “fast” pain that is sharp or pricking, whereas stimulation of C fibers
often results in a slower developing sensation of burning or dull aching
The Spinal Cord
• The most important role of the spinal cord is to provide a pathway for
ascending sensory information and descending motor messages
• Produces the spinal reflexes
• The afferent fibers group together after leaving the skin and this
grouping forms a nerve
The Spinal Cord
The Spinal Cord
• The dorsal horns contain several layers, or laminae.
• allow for elaborate interactions between sensory input from the body and the
central processing of neural information in the brain.
The Brain
• The thalamus receives information from
afferent neurons in the spinal cord
• Somatosensory cortex in the cerebral
cortex
• receives information from the thalamus that
allows the entire surface of the skin to be
mapped onto the somatosensory cortex
• Areas that are particularly rich in receptors
occupy more of the somatosensory cortex
The Brain
• A person’s ability to localize pain on the skin’s surface is more precise
than it is for internal organs.
• Referred pain, when pain is experienced in a part of the body other
than the site where the pain stimulus originates.
• Heart attack & pain in the arm
• Positron emission tomography (PET) & Functional magnetic
resonance imaging (fMRI)
• brain activity occurs when nociceptors are activated
• the human brain reacts in similar ways to emotional and physical pain.
Neurotransmitters and Pain
• Neurochemicals have properties similar to those of the opiate drugs
• They affect the brain to alter pain perception by occupying and activating receptors
• Opiate-like neurochemicals, including the endorphins
• the enkephalins, and dynorphin
• Stress, suggestion, and electrical stimulation of the brain can all trigger the release of these
endorphins
• Glutamate and substance P act in the spinal cord to increase neural firings related
to pain.
• Bradykinin and prostaglandins are substances released by tissue damage; they
prolong the experience of pain by continuing to stimulate the nociceptors.
• Cytokines by the immune system may intensify chronic pain
The Modulation of Pain
• The periaqueductal gray is involved in modulating pain in midbrain
• When it is stimulated, neural activity spreads downward to the spinal cord, and pain relief
occurs
• Endorphins in the periaqueductal gray initiate activity
• Decides whether ignore the pain or
feel the pain
The Meaning of Pain
• Pain was due to two factors:
• the sensation and the person’s reaction to that sensation.
• the multidimensional nature of pain
• the International Association for the Study of Pain (IASP) Subcommittee
on Taxonomy (1979, p. 250) defined pain as
“an unpleasant sensory and emotional experience associated with actual or potential
tissue damage, or described in terms of such damage.”
The Meaning of Pain
• Three stages
1. Acute
• Its duration is normally brief & ordinarily adaptive
• İncludes pains from cuts, burns, childbirth, surgery, dental work, and other injuries.
• it signals the person to avoid further injury
2. Chronic
• endures over months or even years
• type of pain may be due to a chronic condition such as rheumatoid arthritis, or be the result of an injury
that persists beyond the time of healing
• frequently exists in the absence of any identifiable tissue damage.
• not adaptive but, rather, can be debilitating and demoralizing and often leads to feelings of helplessness
and hopelessness
• chronic recurrent pain
• pain marked by alternating episodes of intense pain and no pain (e.g., Headache)
3. Prechronic
• comes between the acute and the chronic stages
• Deal or fail
The Experience of Pain
• The experience of pain is individual and subjective
• Situational and cultural factors influence experience of pain
• E.g., Battle injuries
• Beecher (1956)
• “the intensity of suffering is largely determined by what the pain means to the
patient”
• “the extent of wound bears only a slight relationship, if any (often none at all), to the
pain experienced”
• two-dimensional experience consisting of both a sensory stimulus and an emotional
component
The Experience of Pain
• Individual Differences
• Classically conditioned responses to the associated stimuli
• E.g., dentist fear
• Role of operant conditioning in pain by providing a means for acute pain to develop
into chronic pain
• Being rewarded for pain behaviors
• E.g., headache patients report more pain behaviors and greater pain intensity when their spouses or
significant others respond to pain complaints with seemingly helpful responses, such as taking over
chores, turning on the television, or encouraging the patient to rest
• People who are anxious, worried, and have a negative outlook tend to experience
heightened sensitivity to pain
• Patients suffering from chronic pain are more likely to be depressed, to abuse alcohol
and other drugs, and to suffer from personality disorders
The Experience of Pain
• Cultural Variations
• Cultural background and social context affect the experience
• Social desirability in expression of pain
• behaviors among different cultures may reflect behavioral differences in learning
and modeling
• Gender Differences
• Common stereotype about pain perception is that women are more sensitive to
pain than men
• W reports more than m
• W experience disabilities and pain-related conditions more often than men
• Gender roles and socialization
• For m, be strong & deny pain
• For w, pain is related to vulnerability
• Hormonal differences
Theories of Pain
• Specificity Theory
• Hypothesizing that specific pain fibers and pain pathways exist
• The assumption that pain was the transmission of one type of sensory
information
• Researchers tried to determine which type of receptor conveyed what type of
sensory information
Theories of Pain
• The Gate Control Theory
• Pain has sensory component, motivational and emotional components.
• Modulations begin in the spinal cord.
• The spinal cord act as a gate for the sensory input that the brain interprets as pain
• either increase (open the gate) or decrease (close the gate) the flow of neural
impulses
• Central control trigger consisting of nerve impulses that descend from the brain and
influence the gating mechanism.
• Cognitive processes can influence gate control
• E.g., Anxiety, worry, depression, and focusing on an injury can increase pain
• E.g., Distraction, relaxation, and positive emotions can cause decreasing pain
Theories of Pain
• The Gate Control Theory
• Presynaptic inhibition of pain
• If sensory input enters into a heavily activated
nervous system, then the stimulation may not
be perceived as pain
• Explains how injuries can go virtually unnoticed
Theories of Pain
• Neuromatrix theory
• An extension to the gate control theory
• The neuromatrix, a network of brain neurons
• acts even in the absence of sensory input, producing phantom limb sensations
• Pain perception is part of a complex process affected not only by sensory input but
also by activity of the nervous system, by experience and expectation.
The Measurement of Pain
• Pain is a subjective experience
• Accurate measurement is an issue
1. Self-report ratings
2. Behavioral assessments
3. Physiological measures
The Measurement of Pain
1. Self-report ratings
1. Rating Scales
• Rate the intensity of their pain on a scale from 0 to
10 (or 0 to 100) w/ 10 being the most excruciating
pain possible and 0 being the complete absence of
pain.
• The Visual Analog Scale
2. Pain Questionnaires
• McGill Pain Questionnaire
• Multidimensional Pain Inventory
3. Standardized Psychological Tests
• MMPI-2 for pain assessment is its ability to detect
patients who are being dishonest about their
experience of pain
• Beck Depression Inventory
• Symptom Checklist–90
The Measurement of Pain
2. Behavioral assessments
• observation of patients’ behavior
•
•
•
•
•
•
groan, grimace, rub, sigh, limp, miss work, remain in bed
suffering from pain
lowered levels of activity
use of pain medication
body posture
facial expressions
• Especially useful in assessing the pain of people who have difficulty furnishing
self-reports—children, the cognitively impaired, and some elderly patients.
The Measurement of Pain
3. Physiological measures
• Electromyography (EMG)
• measures the level of muscle tension
• Pain increases muscle tension
• Autonomic indices
• hyperventilation, blood flow in the temporal artery, heart rate, hand surface
temperature, finger pulse volume, and skin conductance level
Pain Syndromes
• Acute pain is both a blessing and a burden
• Chronic pain serves no clear purpose
• categorized according to syndrome
• Headache and low back pain are the two most frequently treated pain
syndromes
Headache Pain
• Headache pain is the most common of all types of pain
• More than 99% of people experiencing headache
• The headache classification committee of the international headache society (IHS)
• The three primary pain syndromes are migraine, tension, and cluster headaches
Headache Pain
• Migraine headaches represent recurrent attacks of pain that vary
widely in intensity, frequency, and duration.
• No clear reason known
• originating in the blood vessels in the head
• complex cascade of reactions that include neurons in the brain stem
• have a genetic component
• Migraine attacks often occur with loss of appetite, nausea, vomiting,
and exaggerated sensitivity to light and sound.
• Migraine headaches often involve sensory, motor, or mood
disturbances
Headache Pain
• Migraines also exist in two varieties:
• those with aura & those without aura
• with aura, have identifiable sensory disturbances that precede the headache
pain;
• w/out aura, have a sudden onset and an intense throbbing, usually (but not
always) restricted to one side of the head.
• Women are two to three times more likely than men to have migraine
headaches
• Most migraine patients experience their first headache before age 30
• However, the period for the greatest frequency of migraines is between
ages 30 – 50.
Headache Pain
• Tension headaches are muscular in origin, accompanied by sustained
contractions of the muscles of the neck, shoulders, scalp, and face.
• Gradual onset
• Sensations of tightness; constriction or pressure; highly variable
intensity, frequency, and duration; and a dull, steady ache on both
sides of the head.
• People with this pain syndrome reported lost workdays and
decreased effectiveness at work, home, and school because of their
pain
Headache Pain
• Cluster headache
• severe headache that occurs in daily or nearly daily clusters
• Some symptoms are similar to those of migraine, including severe pain and vomiting
• but cluster headaches are much briefer, rarely lasting longer than 2 hours
• The headache occurs on one side of the head
• often the eye on the other side becomes bloodshot and waters
• More common in men than in women, by a ratio of 2:1
Low Back Pain
• As many as 80% of people in the United States experience low back pain at
some time
• Most injuries are not permanent, and most people recover
• Those who do not recover quickly have a poor prognosis and are likely to
develop chronic pain problems
• Health care expenditures for these people total more than $90 billion a year
in the United States
• The incidence of low back pain shows some variation for countries around
the world
• produces direct expenses, such as medical care, and indirect costs, such as lost
workdays disability, affecting people in countries around the world
Low Back Pain
• The most frequent cause of low back pain is probably injury or stress
• Pregnancy
• Aging
• Arthritis and osteoporosis
• Infections, degenerative diseases, and malignancies
• Psychological factors such as fear, anxiety, depression, a history of trauma
and abuse, and reinforcement experiences, all of which are more common
among chronic pain patients
Arthritis Pain
• Rheumatoid arthritis is an autoimmune disorder characterized by swelling
and inflammation of the joints as well as destruction of cartilage, bone,
and tendons.
• changes alter the joint, producing direct pain
• changes in joint structure lead to changes in movement, which may result
in additional pain
• It is most prevalent among people 40 to 70 years old.
• Women are more than twice as likely as men to develop this disease
• Rheumatoid arthritis interferes with work, family life, recreational
activities, and sexuality
Arthritis Pain
• Osteoarthritis is a progressive inflammation of the joints that produces
degeneration of cartilage and bone
• It affects mostly older people
• causes a dull ache in the joint area, which worsens with movement;
• the resulting lack of movement increases joint problems and pain
• They often experience feelings of helplessness, depression, and anxiety,
which exacerbate their pain
Arthritis Pain
• Fibromyalgia is a chronic pain condition characterized by tender
points throughout the body.
• Accompanying symptoms of fatigue, headache, cognitive
difficulties, anxiety, and sleep disturbance
• Diminishes quality of life
Cancer Pain
• More than 13 million people in the United States have a cancer diagnosis
(Mariotto, Yabroff, Shao, Feuer, & Brown, 2011).
• Cancer can produce pain in two ways
• through its growth and progression
• through the various treatments to control its growth
• Some cancers are much more likely than others to produce pain.
• Head, neck, and cervical cancer patients experience more pain than leukemia patients
• Across countries, almost half of cancer patients’ pain was untreated
Phantom Limb Pain
• Pain can occur in the absence of injury
• Phantom limb pain, the experience of chronic pain in a part of the body
that is missing
• Amputation removes the nerves that produce the impulses leading to the
experience of pain, but not the sensations
• The sensations often start soon after surgery as a tingling and then develop
into other sensations that resemble actual feelings in the missing limb,
including pain.
• Women who have undergone breast removal also perceive sensations from the
amputated breast
• People who have had teeth pulled sometimes continue to experience feelings from
those teeth
Phantom Limb Pain
• Amputees sometimes feel that a phantom limb is of abnormal size or in an
uncomfortable position
• Phantom limbs can also produce painful feelings of cramping, shooting,
burning, or crushing.
• Phantom pain remains over time
• Pain is more likely to occur in the missing limb when the person experienced
a great deal of pain before the amputation
• Some authorities suggest that phantom limb pain has an emotional basis.
• This neuromatrix pattern continues to operate, even if the neurons in the
peripheral nervous system do not furnish input to the brain.
Phantom Limb Pain
• Brain is capable of reorganization after injury, producing changes in the
nervous system.
• Phantom limb pain may arise from changes that occur in both peripheral
and central nervous systems after removal of the limb.
• Rather than compensate for the loss, the nervous system makes changes
that are maladaptive, creating pain.
Medical approaches to managing pain
• Drugs
• Analgesic drugs relieve pain without causing loss of consciousness
• The opiates and the nonnarcotic analgesics
• Both types exist naturally as derivatives of plants, and both have many synthetic
variations.
• Contemporary opiate painkillers, suchh as morphine, codeine oxycodone,
and hydrocodone
• the development of both tolerance and dependence.
• Tolerance is the body’s decreased responsiveness to a drug.
• When tolerance occurs, larger and larger doses of a drug are required to bring about the
same effect.
• Dependence occurs when the drug’s removal produces withdrawal symptoms.
• Because opiates produce both tolerance and dependence, they are
potentially dangerous and subject to abuse.
Medical approaches to managing pain
• Drugs (cont’d)
• The risk of addiction is less than 1%
• The number of chronic pain patients who develop an addiction to opiate pain medications is less than
4% of the number who are prescribed them
• The best predictor of opiate painkiller abuse is personal history of illegal drug and alcohol use
• People who misuse these substances are more likely to also misuse opiate painkillers
• No other type of drug produces more complete pain relief
• Wariness about abuse of these drugs affects both physicians, who are reluctant to
prescribe them
• People with either acute or chronic pain frequently fail to receive sufficient relief.
Medical approaches to managing pain
• Drugs (cont’d)
• Self-paced administration
• activate a pump attached to their intravenous lines and deliver
a dose of medication whenever they wish, within well-defined
limits.
• Wide acceptance because patients tend to use less
medication, obtain better pain relief and experience higher
satisfaction
• Patient-controlled transdermal delivery system
Medical approaches to managing pain
• Drugs (cont’d)
• Whereas undermedication may be a problem for cancer pain patients, overmedication
is often a problem for patients suffering from low back pain.
• Low back pain patients who use pain medication have poorer outcomes, more health
problems, and higher costs than those who do not.
• The nonnarcotic analgesics include a variety of nonsteroidal anti-inflammatory
drugs (NSAIDs) & Acetaminophen
• Aspirin, ibuprofen, and naproxen sodium appear to block the synthesis of
prostaglandins
• A class of chemicals released by damaged tissue and involved in inflammation
Medical approaches to managing pain
• Drugs (cont’d)
• The nonnarcotic analgesics act at the site of injury instead of crossing into
the brain
• They change neurochemical activity in the nervous system and affect pain
perception
• Pain that occurs without inflammation is not so readily relieved by NSAIDs
• NSAIDs can irritate and damage the stomach lining
• Even producing ulcers
• Aspirin’s side effects include the alteration of blood clotting time, and aspirin and
other NSAIDs are toxic in large doses, causing damage to the liver and kidneys.
• Acetaminophen
• Pain-relieving capability similar to that of aspirin
• Large quantities of acetaminophen can be fatal
Medical approaches to managing pain
• Drugs (cont’d)
• Antidepressant drugs and drugs used to treat seizures also influence pain
perception, and these drugs can be used to treat some types of pain.
• Antidepressants can be useful in treating low back pain
• Some types of anticonvulsant medication can help people with migraine headaches
• Even the variety of drugs and strategies for their use are not adequate for many
people with chronic pain.
• Those individuals may consider surgery or other treatments to attain relief.
Medical approaches to managing pain
• Surgery
• aims to repair the source of the pain or alter the nervous system to alleviate the pain
• Low back surgery is the most common surgical approach to pain
• Surgery can also alter nerves that transmit pain
• This procedure may use heat, cold, or radiofrequency stimulation to change neural
transmission and control pain.
• Another tactic for altering pain through changing nerve transmission involves stimulation of
nerves through implanted wires that stimulate rather than damage nerves.
• Activation of the system produces pain relief by activating neurons and by releasing neurotransmitters
that block pain
Medical approaches to managing pain
• Spinal stimulation is a promising technique for controlling back pain
• Surgery has at least two limitations as a treatment for pain.
• It does not always repair damaged tissue
• It does not provide all patients with sufficient pain relief.
Behavioral techniques for managing pain
• Relaxation training
• Behavioral therapy
• Cognitive therapy
• Cognitive behavioral therapy
Behavioral techniques for managing pain
• Relaxation training
• used successfully to treat pain problems such as tension and migraine,
rheumatoid arthritis, and low back pain
• typically functions as part of a multicomponent program
Behavioral techniques for managing pain
Behavioral therapy
• behavior modification based on operant conditioning
• the goal of behavior modification is to shape behavior, not to alleviate feelings or sensations of pain.
• positive reinforcers that frequently follow pain behaviors
• include attention from family, relief from normal responsibilities, compensation from employers, and medications
that people receive from physicians
• create chronic pain
• works against pain traps
• identifying the reinforcers
• training people in the patient’s environment
• use praise and attention to reinforce more desirable behaviors
• withhold reinforcement when the patient exhibits less desired pain behaviors
Behavioral techniques for managing pain
Behavioral therapy (cont’d)
• Objective outcomes indicate progress
• the amount of medication taken
• absences from work
• time in bed or off one’s feet
• number of pain complaints
• physical activity, range of motion, and length of sitting tolerance
• Behavioral approach can decrease pain intensity, reduce disability, and
improve quality of life
Behavioral techniques for managing pain
Cognitive therapy
• based on the principle that people’s beliefs, personal standards, and feelings of
self-efficacy strongly affect their behavior
• concentrate on techniques designed to change cognitions, assuming that behavior
will change when a person alters his or her cognitions.
• irrational thoughts, are the root of behavior problems.
• Pain-related catastrophizing
• The tendency to catastrophize is associated with the magnification of pain, both acute &
chronic pain
Behavioral techniques for managing pain
Cognitive behavioral therapy
• assumes that thoughts and feelings are the basis of behavior
• modifying environmental contingencies and building skills to change observable
behavior
• includes strategies for addressing the harmful cognitions that are common
among chronic pain patients, such as fear and catastrophizing.
Behavioral techniques for managing pain
Cognitive behavioral therapy (cont’d)
• Pain inoculation program
1. Reconceptualization stage
• patients learn to accept the importance of psychological factors for at least some of their pain
• often receive an explanation of the gate control theory of pain
2. Acquisition and rehearsal stage
• learning relaxation and controlled breathing skills.
3. Follow-through stage
• instructions to spouses and other family members
• ignore patients’ pain behaviors
• reinforce such healthy behaviors
• E.g., Physical activity, decreased use of medication, fewer visits to the pain clinic, or an increased number
of days at work
• construct a posttreatment plan for coping with future pain
• apply their coping skills to everyday situations outside the pain clinic
Behavioral techniques for managing pain
Cognitive behavioral therapy
• Acceptance and commitment therapy (ACT)
• acceptance of the pain
• focusing attention on other goals and activities that individual values
• especially helpful for chronic pain patients
Fin...