Module 3 Pain

Solving the issue of specific questions in 6b)

Be very precise in your answer• 1. Define the perspective you are using

(validity, demand characteristics, usefulness)

• 2. Give evidence for positive / negative aspects of the perspective using studies as examples (Discuss the issue in one or two paragraphs)

• 3. Give a conclusion regarding the perspective

Example 1: Validity (6 sentences)• Psychological studies can have problems of validity which refers to

whether the studies measure what it is meant to measure, i.e., if it is meant to measure aggression, it actually does so. Studies conducted to measure adherence, that is whether patients are actually taking their medicines and following instructions about lifestyle changes can sometimes be invalid. For example, the study by Chung and Naya (2000) used an electronic Track Cap which is an electronic device on the bottle top that recorded the date and time of use of the medication. This method may not be valid as the measures may be more linked to the times the bottle is opened, but not whether the patient actually took the medicine. Patients may open the bottle and throw away the pills. Therefore, psychologists have to be careful in their research design to make sure that they do measure what they set out to measure.

Example 2: Usefulness (5 sentences)• Usefulness of psychological studies refers to whether the

results obtained are applicable to real life situations or to provide remedies for problems identified, such as non-adherence to medical requests. The study by Sherman (2000) on asthma medicines checked adherence by telephoning the patient’s pharmacy to assess the refill rate is useful. The results showed that the adherence rate was quite low (61%). The study allows psychologists to guide doctors and nurses about methods they can use when they want to know how to verify whether their patients are taking their medications. Using refill checks is unreliable and it should be used with caution or together with another method, such as biochemical tests.

Example 3: Ecological validity (5 sentences)

• It is important for studies to be ecologically valid. This means that the studies (design, methods, procedures) are true to real life and the results will better reflect reality. For example, the study done by Riekart and Droter (1999) used real teenagers with insulin-dependent diabetes mellitus following treatment in real clinical settings. The results obtained indicating that self-reports are unreliable methods to measure adherence are therefore true to life and ecologically valid. The results can be taken as generally valid and applicable to this group of patients.

Psychology and Health: Module 3 - Pain

Review: Answer “YES” or “NO”

• 1. Is pain an subjective experience?• 2. It is easy to measure pain.• 3. Pain can exist without injury and

injury can exist without pain.• The 3 theories of pain are not valid.• Pain cannot be measured by self-

reports.• Pain can best be measured by having

patients fill in a questionnaire about their pain experience.

• Explain how patients with congenital analgesia die early.

• Why do medical practitioners have problems to measure pain in their patients?

• How does the GCT explain patients being able to control their pain experience?

•

Module 3 - Pain• Types and theories of pain• Definitions of pain. Acute and chronic organic pain; psychogenic pain

(e.g. phantom limb pain). Theories of pain: specificity theory, gate control theory (Melzack, 1965).

• Measuring pain• Self report measures (e.g. clinical interview); psychometric

measures and visual rating scales (e.g. MPQ, visual analogue scale), behavioural/observational (e.g. UAB). Pain measures for children (e.g. paediatric pain questionnaire, Varni and Thompson, 1976).

• Managing and controlling pain• Medical techniques (e.g. surgical; chemical). Psychological

techniques: cognitive strategies (e.g. attention diversion, non-pain imagery and cognitive redefinition); alternative techniques (e.g. acupuncture, stimulation therapy/TENS).

What is pain?

Types and theories of

pain

Define, in your own words what is meant by the term ‘pain’ / ‘measuring pain’ /

‘controlling pain’.

Pain can be defined as a subjective unpleasant experience (both sensory or physical and emotional) which can be associated with actual or threatened tissue damage or irritation. Pain can exist

without injury and nearly every person experiences pain.

Measuring pain refers to a variety of methods and techniques to assess the type, levels and qualities of pain

experienced by patients. These methods can be self-reports, physiological tests or even behavioural observations.

Controlling pain is defined as the various techniques used by medical practitioners to help patients reduce or eliminate the pain

they experience. These techniques include medicines, such as morphine or physical methods such as massages or even

psychological methods such as hypnosis.

What is Pain?• Unpleasant sensation related to the perceived or real

affected body part• Perception of actual or threatened damage• Perception based on expectations, past experience,

anxiety, suggestions, cognitive factors– Acute– Chronic

• The experience of pain is (individual differences) very subjective

• Simple Spinal Reflex Arc

Describe two types / causes of pain.

Types of Pain

Organic – physical basis for the pain felt

Psychogenic – there is no physical basis

for the pain felt

Acute Chronic

Chronic recurrent pain

Chronic intractable benign pain

Chronic progressive pain

Phantom-limb pain

Two main categories (types) of pain:Acute & Chronic

• Acute - is a relatively brief sensation, usually less than six months duration - usually a response to a specific trauma - forms the basis for danger warnings and subsequent learning.

• Chronic - lasts more than six months - exists beyond the time for normal organic healing.

• The pain begins to impair other functions Patients may begin to experience learned helplessness and hopelessness this leads to the classic signs of depression (lethargy, sleep disturbance, weight loss)

• May quit work and adopt a self imposed invalid existence.

Chronic Pain

• Characteristics of– Symptoms last longer than 6 months– Few objective medical findings– Medication abuse– Difficulty sleeping– Depression– Manipulative behavior– Somatic preoccupation

Categories of Chronic Pain

• *Chronic recurrent pain -- benign condition consisting of intense pain alternating with pain-free periods, e.g., migraine, tension headaches.

• * Chronic intractable-benign pain -- benign condition where pain is persistent with no pain free periods, although the pain may vary in intensity, e.g., lower back pain.

Categories of Chronic Pain

• * Chronic progressive pain --malignant condition where pain is continuous and increases in intensity as the organic condition (disease) worsens e.g., cancer & rheumatoid arthritis.

Phantom Limb Pain• Melzack (1992) 7 features 1. Phantom limb feels real. Sometimes amputees try to

walk on their phantom limb. 2. Phantom arm hangs down at the side when resting.

Appears to swing in time with other arm, when walking.

3. Sometimes the phantom limb gets stuck in awkward position. If it is behind the patients back, then patient feels obliged to sleep on stomach.

4. Artificial limb appears to fit like a glove. Patients see artificial limbs as parts of their body.

5 Phantom limbs give impression of pressure & pain.

6 Even if phantom limb is experienced as spatially detached from the body, it is still felt to belong to the patient.

7 Paraplegic people experience phantom limbs. They can even experience continually cycling legs.

Phantom limb pain

• Not just the cut nerve endings (neuromas) sending messages to the brain, because cuts made along the neural pathways only produce a temporary relief from pain.

• Melzack believes that the brain has a map or a neuromatrix of the body image.

• Connections to this neuromatrix - sensory systems, emotional & motivational systems.

• It is the emotional and motivational systems that cause the phantom limb experience.

Phantom Limb Pain

• Neuromatrix pre-wired - young amputees experience phantom limb pain.

• People born without limbs also experience phantom limb pain.

Other types of pain

Congenital Analgesia

• When she was examined by a psychologist (Charles Murray) in 1950 she did not feel any pain when she was given strong electric shocks or when exposed to very hot and very cold water.

• When these stimuli were presented to her she showed no change in heart rate, blood pressure or respiration. She did not remember ever having coughed or sneezed, and did not show a blinking reflex.

• She died at the age of 29 as a result of her condition.

Congenital Analgesia

• Although during a post-mortem there were no obvious signs of what had caused the analgesia in the first place, she had damaged her knees, hips and spine.

• This damage was due to the fact that she did not shift her weight when standing or sitting, did not turn over in bed and did not avoid what would normally be considered to be uncomfortable postures. This caused severe inflammation in her joints.

Congenital Analgesia

• Although there is some evidence that this condition may be inherited, there are other causes such as neurological damage.

• However, some cases cannot be explained in this way. Most people with this condition learn to avoid causing themselves too much harm but, as in the case of 'Miss C, may die as a result of the problems caused by the analgesia.

Episodic Analgesia

• Serious injury (e.g., loss of limb) - little pain felt. • 6 characteristics (Melzack and Wall 1988).

1. The condition has no relationship to the severity or the location of the injury.

2. No simple relationship to circumstances - occurs in battle or at home.

3. Victim fully aware of injury but feels no pain

Episodic Analgesia

4. Analgesia is instantaneous

5. Analgesia lasts for a limited time

6. Analgesia is localised, pain can be felt in other parts of the body (Arm blown off is not felt, but injection is!)

Episodic Analgesia

• Carlen et al (1978) - Israeli soldiers - Yom Kippur War. Loss of arm - 'bang', 'thump' or 'blow'.

• Melzack, Wall and Ty (1982) - 37% of accident victims reported the experience of episodic analgesia.

Fibromyalgia: Pain Without Injury• The occurrence of body-wide pain in the absence of

tissue damage, as in fibromyalgia, interferes with all aspects of a person's life and undermines their credibility. The problem is that normal activities can be exhausting, sleep is disturbed, the ability to concentrate is impaired, gastrointestinal function is often abnormal, persistent headaches are common, and the unrelenting pain that no one can see is often detrimental to their personal and professional lives--as it creates a "credibility gap."

Pain - Injury• Neuralgia - sharp pain along a nerve pathway.• Causalgia - burning pain• Both develop after wound or disease has ended.

Triggered by a simple stimulus e.g., breeze or vibration.

• Physiological cause of headaches not known.• Melzack and Wall (1988) report that migraine causes

dilation of blood vessels, not the other way around! Pain out of proportion to the injury.

• Some cancers produce little pain until they are advanced. (Serious illness, little pain). Kidney stones are not serious, but produce excruciating pain.

Purpose of pain

• Prevents serious damage. If you touch something hot, you are forced to withdraw your hand before it gets seriously burnt.

• Teaches one what to avoid

• If pain is in joints, pain limits the activity, so no permanent damage can occur.

• but pain can become the problem, and cause people to want to die.

Pain Theory: Historical Perspectives

• Theories regarding the cause, nature, and purpose of pain have been debated since the dawn of humankind.

• Most early theories were based on the assumptions that pain was related to a form of punishment.

• The word “pain” is derived from the Latin word “poena” meaning fine, penalty, or punishment.

Old and new theories of pain• Specificity theory– 4 types of sensory receptors – heat, cold, touch, pain– A nerve responded to only one type– Nerve was continuous from the periphery to the brain

• Pattern theory– A single nerve responded to each type of sensation by creating

a code (i.e., like different ring tones)

• Gate control theory– Melzack & Wall, 1965 – the basis for theories today– Non-painful stimulus can block the transmission of a painful

stimulus

Pain – Melzack & Wall (1965) Gate Control Theory

Melzack & Wall’s Theory of Pain (1965)

What opens the gate?

• Physical FactorsBodily injury

• Emotional FactorsAnxiety & Depression

• Behavioural FactorsAttending to the injury & concentrating on the pain

What Closes the Gate?

• Physical PainAnalgesic Remedies

• Emotional PainBeing in a ‘good’ mood

• Behavioural FactorsConcentrating on things other than the injury

What else closes the gate?Friction – when you rub a part of your body it causes friction, friction signals compete with pain signals to pass through the gate, if both signals are trying to get through, the friction signal will make it first.

Past Experience of PainBeecher (1946 & 1956) looked at requests for pain relief amongst soldiers and compared these to the request made by civilians with the same injuries. Most of the soldiers claimed not to perceive any pain and only a quarter of them requested pain relief.

80% of civilians asked for analgesic support. Beecher argued that the context in which the pain was experienced had an impact on the way in which it was perceived.

Evaluation of the Gate-Control Theory

• For• Experiments with

animals (rats) show that stimulating certain areas of the brain produce numbing effect on animals & humans

• Most influential model of pain so far

• Against• GCT still assumes simple

stimulus-response model of pain

• No evidence of a ‘gate’• Still considers physical &

psychological processes as separate

Describe what psychologists have found out about pain / measuring of pain...

Measuring Pain

How would you do it?• Your patient is 15 years old who has been in a car accident.

He is hospitalised and is taking pain medications for a broken arm.

• Your patient is an elderly woman who has broken her hip when she slipped on the tiles in her kitchen. She is unable to speak.

• Your patient is the schizophrenic, with hypomanic states. He is the 37 year old man, who lives alone and also has severe migraines from time to time.

Difficulty to measure pain

• Doctors often have problems assessing levels of pain• Why?• It is not their own experience• Experience of pain is subjective• Expression of pain is subjective

• For example:• Soldiers and civilians have different levels of pain

experiences & requests for pain medications

Which is the better way to measure pain?

• Self reports – simply ask patients about their pain

• Psychometric measures – tests to determine pain levels

• Visual Analogue Scale – have pictorial or visual depictions of pain

• Behavioural scales / Observation of patients – study patients to see if they are in pain or not or their levels of pain being felt

• Pain measures for children – find ways to know if children are experiencing pain

Use self-reports ???

Subjective methods:Clinical Interviews

• How severe is your pain?

• Describe your pain...

• Rated from ‘not at all’ (0) to ‘extremely’ (100)• Verbal scales: describe your pain– No pain–Mild pain–Moderate pain– Severe pain–Worst pain

Evaluation • Validity Self reports are subjective and it may

be difficult to prescribe exact doses of medicines to control pain. However, pain experience is itself also subjective.

• Usefulness– Give an indication of what patients are feeling, but unfortunately self reports may not be useful to prescribe doses of medicines. Behavioural measures to control pain would be more useful when self reports are used.

Use objective methods ???

• Psychometric measures?

• Visual rating scales?

The McGill Pain Questionnaire (MPQ)

– Part I: is used to localize the pain and identify whether the perceived source of the pain is superficial (external), internal, or both.

– Part II: incorporates the visual analogue scale.

– Part III: is the pain rating index, a collection of 76 words grouped into 20 categories. Patients are to underline or circle the words in each group that describes the sensation of pain being experienced.• Groups 1-10= somatic in nature• Groups 11-15= affective • Group 16= evaluative• Group 17-20= miscellaneous words that are used in the

scoring process.

Evaluation

• Ecologically valid & useful - used in clinical settings with real patients

• However, patients need high level of literacy and awareness to respond to the MPQ; therefore, it lacks validity and reliability– Can anyone explain how the MPQ lacks validity or

reliability?

Pain Scales

• Visual Analog Scale

• VAS typically consist of a 100 mm horizontal line with anchors indicating "no pain" at the left endpoint and "worst pain possible" (or a comparable term) at the right endpoint.

None Severe

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Visual analogue scales can be improved by having verbal or pictorial scales.

Examples of Visual analogue scales

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Examples of Visual analogue scales

Evaluation

• Patients can mark a continuum of severity from "No Pain" to "Very Severe Pain“

• Simple and quick to use and can be filled out repeatedly

• Can track the pain experience as it changes - this could reveal patterns such as situations or times of the day when the pain is better or worse

Evaluation• This method has adequate reliability, however limits

pain to a single dimension (intensity, relief)• Downie et al., evaluating degree of agreement

between various scales in patients with rheumatic diseases, found high correlation among different types of scales.

• Simple to understand & do not demand high degree of literacy or sophistication on the part of patients, unlike other pain measurement tools, such as the semantic differential scales (MPQ).

Evaluation

• The Visual Analogue Scale is simple and quick to administer, and may be used before, during, and following treatment to evaluate changes in the patient's perception of pain relative to treatment.

• The scales may also be completed throughout the course of a day to assess change in pain intensity relative to activity or time of day.

Evaluation• Verbal, numerical, and visual analogue scales cannot be

used with all patients.

• Ineffective with patients who have cognitive or motor problems, in patients who are unresponsive (e.g., due to injury), & in young children and elderly patients.

• Pain often cannot be accurately described & measured on the basis of severity alone. Qualities of the pain are absent.– It is like describing sight only in terms of light or dark, without

regard for colors, patterns, or textures.

What about using behavioural and observational scales?

UAB Pain Behaviour Scale

• A commonly used example of an observation tool for, assessing pain behaviour is the UAB Pain Behaviour Scale designed by Richards et al (1982).

• 10 target behaviours and observers have to rate how frequently each occurs.

• The UAB is easy to use and quick to score; it has scored well on inter-rater and test-retest reliability.

Evaluation

• Correlation between scores on UAB & on MPQ is low indicating that the relationship between observable pain behaviour & self-reports of the subjective experience of pain is not a close one.

What about measuring physiological signs to identify

levels of pain???

Physiological measures of pain• Muscle tension is associated with painful conditions

such as headaches and lower backache, and it can be measured using an electromyograph (EMG). This apparatus measures electrical activity in the muscles, which is a sign of how tense they are.

• Evaluation• Some link has been established between headaches

& EMG patterns, but EMG recordings do not generally correlate with pain perception (Chapman et al 1985) and EMG measurements have not been shown to be a useful way of measuring pain.

electromyograph (EMG).

Physiological measures of pain

• Another approach has been to relate pain to autonomic arousal. By taking measures of pulse rate, skin conductance and skin temperature, it may be possible to measure the physiological arousal caused by experiencing pain.

• Finally, since pain is perceived within the brain, it may be possible to measure brain activity, using an electroencephalograph (EEG), in order to deter mine the extent to which an individual is experiencing pain.

Physiological measures of pain

• It has been shown that subjective reports of pain do correlate with electrical changes that show up as peaks in EEG recordings.

• Moreover, when analgesics are given, both pain report and waveform amplitude on the EEG are decreased (Chapman et al, 1985).

Evaluation

• The advantage of the physiological measures of pain described above is that they are objective (that is, not subject to bias by the person whose pain is being measured, or by the person measuring the pain).

• On the other hand, they involve the use of expensive machinery and trained personnel.

• Their main disadvantage, however, is that they are not valid (that is, they do not measure what they say they are measuring). For example, autonomic arousal can occur in the absence of pain — being wired up to a machine may be stressful & can cause a person’s heart rate to increase.

Evaluation• If someone is very anxious about the process of

having his or her pain assessed, or else is worried about the meaning of the pain, this will cause physiological changes not necessarily related to the intensity of the pain being experienced.

• Autonomic responses can be affected by many other factors such as diet, alcohol consumption & infection, e.g., infection present can get increased pulse rate.

• Better to be used as a signal for the presence of pain rather than as a direct indices of pain.

Measuring pain in children

• How can this be done in a reliable & valid way?

• We already know that measuring pain in adults is very difficult due to validity & reliability issues

Various pain assessment tools are available for children who are old enough to communicate. Pain scales have been developed using numbers, colors, and facial expressions.

In preverbal children, several pain scales have been validated. The CHEOPS (Children’s Hospital of Eastern Ontario Pain Scale) is a well-validated tool for the assessment of pain in children.

It was initially developed for postsurgical patients, but has been used broadly since.

Varni & Thompson Paediatric Pain Questionnaire (PPQ)

• A multidimensional questionnaire for assessing childhood pain, with separate forms for:– Paediatric patient (child)– Parent– Clinician.

• Modeled after McGill Pain Questionnaire (Melzack, 1975).• PPQ assesses physician, patient, & parent perceptions of the

patient's pain experience in a developmentally appropriate format.• More specifically, this instrument measures pain intensity, location,

and the sensory, evaluative, and affective qualities of the pain.

• The different forms use different formats, such as using colours for younger children & descriptive terms for adolescents.

• PPQ has been translated into numerous languages, inc. Danish, French for France & for Canada, Norwegian, Portuguese for Brazil, Spanish for the United States, & Swedish.

Evaluation• In terms of psychometrics, good test–retest estimates for

1-week, 3-week, and 6-month intervals and correlations between child, parent, nurse, and physician ratings of present pain and worst pain have been found for the PPQ.

• Furthermore, significant cross-informant ratings have been obtained but correlations have been higher between parent–child versus those with physicians.

• Considered as "well-established.“= valid + reliable

Managing & controlling pain

Medical techniques

• 2 main possibilities:– Medication– Surgery

• Other physical methods:– Massage– Applying heat– Transcutaneous Electrical Nerve Stimulation (TENS)

What type of surgery can be done to alleviate pain?

• Severing nerves, either at the periphery or in the central nervous system (spine & brain)

• Implanted pain control systems– Implanted pain control systems involve inserting

devices under your skin or elsewhere in your body. The devices use medicine, electric current, heat, or chemicals to numb or block pain.

Implanted pain control systems

• Intrathecal drug delivery sends medicine to the area of your pain.

• Electrical nerve stimulation uses electric current to interrupt pain signals.

• Nerve ablation destroys or removes the nerves that are sending pain signals.

• Chemical sympathectomy uses chemicals to destroy nerves. This treatment may be used for a type of chronic pain called complex regional pain syndrome, which affects the nervous system.

Medicines…? But, what types??

• Over-the-counter (OTC) pills, e.g., aspirin (acetylsalicylic acid), acetaminophen (Paracetamol, Panadol / Tylenol / Advil)– Non Steroid Anti-Inflammatory Drugs

(NSAIDS)

• Opioids – codeine, morphine

• Implantable drug pumps

Chemicals

• Aspirin, Ibuprofen, Paracetamol (acetaminophen)– Against pain– Against inflammation– Against fever

Opium used before then, as early as 1550 BC

Evaluation - surgery

• Immediate relief by going to the source of the problem

• Done under doctor’s supervision• BUT• Invasive• Expensive• Time-consuming• Does not always work

Evaluation - Medications• Immediate relief• Self-management• OTC available & easily accessible• BUT• Lots of side-effects (Aspirin – stomach lining burn, ulcers,

thins the blood excessive bleeding)• Opioids are very addictive; needs medical supervision. Can

be diverted to illicit markets.– Solution? Disguise taste, reduce doses, give in regular intervals &

not when requested by patients, use psychological techniques• Tolerance develops quickly = needing higher doses.

Evaluation

• Not known how heat works, but fits in with the gate theory (closes the gate)

• Mild pulses of electricity in painful areas probably works in the same way.

• Suitable for some patients, not all (Remember: customising treatment)

Psychological techniques• Relaxation• Biofeedback• Hypnosis• Cognitive coping skills• Operant techniques• Mental imaging• Self-efficacy• Counselling

Evaluation• Hypnosis produces a high degree of analgesia in only a

minority of individuals.

• Those people who can be hypnotised very easily and deeply seem to gain more pain relief from hypnosis than those who are less hypnotically susceptible.

• Hypnosis could be seen as a form of relaxation.

• Hypnosis often produces states of heightened attention to internal images and inattention to environmental stimuli.