Health Psychology Pain

Requirements Types and theories Measuring Controlling and managing Use first three studies, last two more for information

Types (and Theories of Pain) Background EPISODIC ANALGESIA Injury without pain NEURALGIA Sudden, sharp pain along nerve pathway after nerve disease has ended CASUALGIA Burning pain after deep wound has healed PHANTOM LIMBS Sensations in a missing limb PUPOSE OF PAIN Warning, learning, limit activity – a necessary evil NOCICEPTION Detection of tissue damage by specialised nerves FEELING PAIN Nociception, perception, suffering, behaviour

Theories of Pain Specificity theory Pattern theory Gate control theory Special system of nerves carry messages from receptors to pain centre of brain FOR – specialised receptors heat/touch AGAINST – injury without pain, neurographs Pattern theory No separate system for perceiving pain, but shared with senses like touch 3 types receptor – nociceptor (pain only), Stimuli receptor (strong or weak stimuli), Touch receptor (touch only not pain) Gate control theory Biopsychosocial approach Activity in pain fibres – open gate, activity in sensory nerves – close gate (rubbing, scratching), messages from brain – anxiety/excitement opens/closes – explain distraction working Neuromatrix Brain’s image of body on which sensory data is played out - holgram

Measuring Pain Background Karoly – elements; sensory, neurophysiological, emotional, behavioural, impact, information processing Interview Time consuming and interpretation complex Questionnaire/Rating Scales Interpretation and language Generally reliable and valid Physical measure Pain threshold and just noticeable differences Pain tolerance, drug request point, pain sensitivity range

Controlling Pain Background Chemical treatment Analgesic (aspirin, acetimonphen, opiates) Placebos Treatment with no obvious active ingredient Ethics Surgery Trigeminal neuralgia – destroy nerves to facial area (numbness) Physical therapy Manual – massage Heat – microwave diathermy, ultrasound – deep tissue injury. Does the heat close the gate? Cold – ice pack Acupuncture Electrotherapy Spinal cord stimulation Deep brain stimulation TENS/PENS Psychological treatment Operant conditioning – social reinforcement, increase exercise and rest, reduce drugs, training to not reinforce pain behaviour Coping Reinterpretation of pain, physical relaxation methods, distraction Cognitive behavioural therapy Change maladaptive behaviour, change self-statements, change assumptions and beliefs

3 Short Summaries Pain is a complex experience with a variety of psychological and physiological components. Although we have an understanding of some of the factors that increase or reduce pain we do not yet have a complete picture of it. As with all attempts to measure behaviour and experience, pain poses a number of problems, including the need to rely on self-reports of people with pain. They, in turn, have to make comparative judgements about their pain without ever knowing what pain is like for other people. Although we only have sketchy understanding about he causes of pain there are a wide range of treatments to relieve it. These treatments include physiological, physical, cognitive and behavioural treatments which often work best when used in combination.

Pain – study 1 Bigatti Who What Results 2002 Pain measures & fibromyalgia Quasi-experiment, testing instruments for validity, reliability, ease of use 602 informed What Pain level measured using 5 common pain scales (pain rating perception, pain index intensity, words chosen intensity, manual tender point weights, visual analogue mark line) + arthritis self-efficacy scale (pain, symptoms, self-efficacy) + fibromyalgia impact (health physical, psychological, social, global) + Pittsburgh sleep quality Correlated with each other and other measures Results Correlation between the first 5 pain scales – concurrent validity. Visual scale most correlated with other scales and the extra 3 scales. Easy to use and patients feel comfortable with it.

Pain – study 2 Strujis et al Who What Results 2003 Fake manipulation of tennis elbow 31 all had tennis elbow, informed, excluded if other symptoms What 2 treatment groups – random. 1 – manipulation 9 sessions, devised for the study. 2 – ultrasound, massage, stretch & strengthen, 9 sessions Independent practitioner administered. Researcher blind to group At outset, 3 weeks, 6 weeks – global measurement of improvement (1-6 scale), severity of complaint (pain), pain free grip & maximum grip force Examined using statistical analysis Results No significant differences at outset 3 weeks – 62% manipulation group – successful; 20% normal treatment 6 weeks – manipulation group decrease pain during day No other differences between groups

Pain – study 3 Luffy Who What Results 2003 Paediatric pain measurement 3 tools Experiment 100 African-American children 3-18y, sickle cell anaemia, 49% female. All speak English, cognitively able (checked) Informed consent and assent What Divided into three age groups. Interviewed (parent present) recount 2 painful procedures. Asked which was most painful. Rated on 3 scales and repeated again after a minimum of 15 minutes. Counterbalanced presentation of tests. Oucher Scale (numerical or pictorial); Wong/Baker (select a picture of a face which matches pain); VAS (line) If the procedure identified as most painful was rated with the highest pain threshold then a score of 1 given – if not a score of 0. Consistent responses totalled and divided by number of participants – percentage validity for group. With retests - Score 1 if VAS within 5mm, score 1 if same picture chosen for face. Given all three tests and asked which they preferred – ranked Results 17/100 children could not use the VAS Retest reliability – 38% oucher, 37% faces, 29% VAS. If slight variation allowed then 70%, 67% and 45%. Faces 56% prefer, oucher 26%, VAS 18%

Study 4 Melzack & Wall 1965 Gate control theory Neural gate in dorsal horn of spinal cord. Three factors open and close gate. Amount of activity in small pain fibres, amount of activity in peripheral fibres, messages descending from brain. Decrease pain by preventing pain reaching the gate or increase large peripheral fibre stimulation and close the gate. Also get brain to think in positive way therefore send message to close gate.

Study 5 Melzack & Togerson Who What Results 1971 Language of pain Doctors, patients, graduates, students What Classify adjectives into groups describing pain aspects (doctor and graduate) Doctor, patient, student rate each group for intensity Results Part 1 – 3 groups; sensory (feels like, location, intensity, duration, quality) – affective (emotional feeling) – evaluative (subjective feeling – e.g. unbearable, troublesome). 16 sub-groups Pain is multi-dimensional, physical sensation, subjective experience, emotional response, has a meaning.

General Review Ethics Reliability/validity Reductionism Strujis – did they experience more pain? Bigatti – the manual tender point examination Luffy – avoids using recall Reliability/validity Bigatti and Luffy found measures to be valid and reliable – for specific groups Luffy may have been testing memory with the older participants since they remembered which they chose rather than being reliable Reductionism Scales – physical and emotional experience not captured by selecting a number, not a meaningful account of reality Ecological validity Relationship between procedure and everyday life Strujis & Bigatti – real patients in pain used Luffy – excluded those in pain for ethical reasons but reduced ecological validity as recall and memory being tested

Questions Describe what psychologists have found out about what pain is and how we can measure it. Disucss the psychological evidence on pain and its measurement. Suggest one psychological technique that could be used to reduce chronic back pain. Give reasons for your answer. Describe one theory of pain (6) Contrast one theory of pain with another theory of pain (10) Describe one way of measuring pain (6) Discuss the validity of measures of pain (10) Describe one method of controlling pain (6) Discuss the effectiveness of methods of controlling pain (10)