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Lecture 7

Lecture 7.docx


Department
Psychology
Course Code
PSY333H1
Professor
Nevena Simic
Lecture
7

Page:
of 18
Lecture 7
Pain and Its Management
Pain:
- an unpleasant sensory and emotional experience associated with actual or potential tissue
damage, or described in terms of such danger
definition by International Association for the Study of Pain (IASP)
Case Study: Miss C
- Normally developing women of average intelligence
- Never felt any pain; as a child
o bit off the tip of her tongue while chewing food (didn’t know)
o have 3rd degree burns from a radiator
o can’t remember ever sneezing or coughing, no gag reflex or corneal reflex
- Physicians studied her: electrical shocks, immerse hands in hot/cold water, pinched
o no changes in heart rate, blood pressure or breathing
- Severe medical problems: knees, hips, spine (remain in one position too long) inflammation
of joints)
o She never readjusted her positions
o neglect injuries infection
no treatment
- Died at age 29 from massive infections
Significance of Pain:
- Pain = symptom of chief concern to patients
o Leads them to seek medical attention
- Pain often considered of secondary importance to MD
o Physicians see pain to a consequences to another illness
- Patients fear ain in illness and treatment most
o Fearing that they cannot relieve suffering increase anxiety
o Most common reason for euthanasia
- $4 billion is spent annually in Canada on over-the-counter pain medications
Why do we feel pain?
- Pain is adaptive
o Tells is to avoid behaviours that may hurt us
o Forces us to rest and recover after an injury
- Can be reflexive and unconscious
o Hot stove burner (pull away hand before you think about the pain)
- Can be used as a learning mechanism
o Electric shock for rats
o Spanking for children
Pain as an Inhibitory Mechanism:
- Learning is conditioning
- Classical conditioning
o Ivan Pavlov’s dog
o Got his dog and put out juicy meat, and everytime he saw the meet he would salivate
o Salivating = unconditioned response
o Meat = unconditioned stimulus
o Take the meat and pair it with a neutral stimulus (that would not elicit salivation)
o Eventually pairing the sound with the food, the dog came to associate the sound with
the presentation of food
Would eventually salivate to the sound without the food
Salivating to tuning response = conditioned response
Sound = conditioned stimulus
- Operant Conditioning
o Learning based on consequences
o Positive = add, negative = take away
o Reinforcement: consequences increases likelihood of behaviour in the future
Positive reinforcement: application of desirable stimulus (reward, candy)
Negative Reinforcement: removal of a negative stimulus (don’t have to do a
chore if good)
o Punishment: consequence decrease likelihood of behaviour occurring in the future
Positive Punishment: application of an aversive stimulus (spanking)
Negative Punishment: take away something good (TV time)
- Using pain to learn
o Therefore, positive punishment and negative reinforcement as a learning mechanism
o These involve aversive, potentially painful stimulus e.g. Electric shock, spanking and
soothing burns
How do we know when someone is in pain?
- Pain Behaviours: are behaviours that occur in responses to pain such as:
1. Facial and audible expressions of distress
2. Distortions in posture of gait
3. Negative affect
4. Avoidance of activity
- Verbal Reports:
o Use of informal vocabulary to describe pain
i.e. a throbbing pain has different implications then does a shooting pain
o Pain questionnaires (McGill Pain Questionnaire) provides indications of the nature of
pain, as well as the intensity
o Can also measure psychosocial measures of pain
i.e. fear it causes
What is pain - Elusive Nature
- Pain is a subjective experience
o Degree to which pain is felt and how incapacitating it is depend on how it is interpreted
- Heavily influenced by context in which it is experienced
o Beecher`s example of soldiers versus civilians
25% wounded soldiers ask for morphine versus 80% of civilians after surgery
What is pain for the soldier? For the patient?
Soldier: pain indicated that they were alive and survived an injury
Civilian: meant that they were being taken away from their regular
routines
o Sports injury continue to play
SNS arousal diminishes pain sensitivity
Stress and psychological distress aggravate experience of pain
What is Pain?
Can be different sensations:
- sharp pain
- dull ache
- blistering
- small but irritating
Pain can be categorized based on the time interval:
Acute Pain
- intense
- short-lived
- disappears as injury heals
- less than 6 months
Chronic Pain
- Begins as acute
- Doesn’t go away
e.g. lower pain
- recurrent acute (e.g. headache) vs intractable-benign (e.g. lower back pain) vs progressive (e.g.
cancer)
Pain in the Lab
- How can we quantify how much pain someone is feeling?
- Method of cold-pressor task
o Submerge hand in cold water until experience pain push a button
o Indicates they have reached pain threshold (point at which you start to feel pain)
o Pain Tolerance level
Duration of time person is willing to endure a stimulus beyond where it began
to hurt
Or intensity of stimulus a person will endure beyond the point where it began to
hurt
Can’t stand it anymore = level of pain tolerance
Variables Contributing to Pain Perception:
Despite a clear physiological role for pain, we know psychosocial factors also produce pain
e.g. upto 85% of back pain comes from people who don’t have physiological reasons
variables contributing to pain perception
- stress
- sternback (1986): headaches in low stressed (7%) vs. moderate stress (17%) vs. highly stressed
(25%)
- Git et. al. (2004): more stress on a given day report increased pain on that day and increased use
of healthcare (ER visit, calls to doctors etc)
- Walker et. al (2001): children with recurrent abdominal pain report more stress.