Dimensions of pain
- Types; stabbing, shooting, throbbing, aching
- Severity: non, mild, severe
- Pattern: continuous, intermittent
- Chronic pain varies by age: lowest in 18-25, highest in 75+
- More common in females than males
How is pain assessed?
- Beyond self report, look at pain thresholds
- Cold pressor task: measures body response to cold water. Count how many seconds until don't want to tolerate anymore.
- Pressure pain: automated device, how much pressure will you tolerate until you decide it is pain (label as pressure to pain)
- Sensation from warmth/heat to pain.
- Pressure pain thresholds vary by location (diff parts of body) and between people and within people over time.
- Variability in pain threshold is bigger than sensations such as warmth.
- Same with mechanical pressure, can detect different pressures but range for pain is very large.
Visual analogue scale
- Table/graph between clinical severity and pain experience.
- Different between people and does not necessarily rely on severity.
Twin studies and pain
- In pain, heritability estimates range from 25-60% suggesting that some of the variation in pain sensitivity is genetically driven.
- Genetic differences in perceptions of pain.
- Unsuccessful in identifying specific genes.
How is pain processed?
- Classic models assumed individual nerves (nociceptors) transmitted pain and that was it.
- Challenged by several observations-
- Phantom limb pain: may people with amputated limbs report pain
- Intact pain neurons but no experience of pain: congenital insensitivity to pain
- Psychosocial factors modulate pain sensitivity and reporting
Gate control theory
- A 'gate' at spinal column controls whether pain receptors in the skin and organs is transmitted on to the brain.
- "gate" can incorporate both information from periphery along with info from the brain down eg. emotions, cognitions.
- Balance of activation from peripheral pain signals and inhibition from brain results in final pain experienced/perceived.
- Gate control theory integrates and accounts for psychosocial modulation of pain experiences, but does not account for things like phantom limb
Neuromatrix theory of pain
- Pain is a multidimensional experience
- Activation of a broad neural network triggers the experience of pain.
- Network may be activated by sensory input from nociceptors, but the network once established may also get triggered independent of sensory input.
- Essentially pain is a 'brain' level phenomenon.
- Neuromatrix can incorporate a number of factors including psychosocial, cognitive, attentional factors in the experience of pain.
Pain and Affect
- Although pain includes a sensory component, the experience also involves an affective component.
- The same way that fear or distress are emotions that serve to push us to act, the affective component of pain motivates us to seek ways to resolve pain.
- Imaging studies show that acute pain cessation is associated with activity in the NUcleus Accumbens, a brain region associated with processing of aversion and reward (relief).
- In people wiht chronic pain, no 'relief' if acute pain stops but chronic is still there.
- Some suggestion that chronic pain begins to be processed more heavily in regions of the brain associated with affective responses
Pain and affect continued
- Even people with chronic pain compared to baseline: inducing positive mood improves pain tolerance, inducing negative mood decreases pain tolerance.
- Longitudinal studies show that: people with chronic pain who are not depressed at baseline are several time more likely to develop depression to people without chronic pain.
- People who are depressed but do not have chronic pain are more likely to develop chronic pain over time than people who had neither at baseline.
- Bi-directional relationship between pain and mood.
Pain and hand holding
- Hand holding has shown pain reducing effect
- Co-activity in brain regions higher in hand holding than no hand holding conditions
Pain and coping in adults
- Active coping: purposely engaging in adaptive cognitive behavioural strategies to manage pain. Linked to lower levels of pain, improved depression, fatigue and medical adherence.
- Passive coping: withdrawing or giving up instrumental control over pain. Linked to higher levels of pain, functional disability or depression.
- Emotion-focused coping: efforts to regulate emotional responses to stressor. Linked to increased pain.
- Positive religious and spiritual coping: linked to positive mood and social support
- Negative religious etc: linked to less positive mood
- Catastrophising: the tendency to focus on and exaggerate the threat value of painful stimuli and negatively evaluate one's ability to deal with pain: heightened pain and disability
- Self regulatory treatments: biofeedback, relaxation training, mindfulness
- Behavioural treatments: operant, fear avoidance
- Cognitive behavioural treatments
- Acceptance and commitment therapy
- Connected to some continuous marker of behavior/physiology
- – breathing
- – Heart rate
- – Brain monitoring, etc.
- Practice becoming aware of these changes and attempting to modulate them
- Often combined with other treatments
- Identify states of tension in mind or body
- Apply some technique for relaxation:
- Deep breathing
- Progressive relaxation: start at bottom of body, tense and relax muscle groups gradually moving up.
- Mindfulness meditation benefits on: stress management, pain management
- Involves: relaxation, focused attention on present moment without interpretation/labelling
- Experience present in 'raw' form
- "detached observer' of own experience
Mindfulness can help detach sensation of pain with the affective experience of distress associated with pain
Operant behaviour therapy
- Typically targets fear behaviours: verbalisation, facial expressions, guarded/restricted movement
- These behaviours may be naturally reinforced; guarded movement may temporarility result in some pain reduction.
- Facial expressions lead to support/sympath.
- Not all these behaviours may be helpful.
- Guarded movements may not reduce actual damage and may put strain on other regions causing new damage.
- Fear avoidance may drive people to avoid a variety of experiences associated with fear or potentially painful experiences.
- Can exacerbate problems through disuse or promoting unhelpful behaviours (eg. reducing physical activity)
Cognitive behavioural therapy (CBT)
- Goal oriented, structured therapy targeting behaviours and cognitions and emotions that may be unhelpful
- Try to reduce unhelpful behaviours.
- Education around role of cognitions and behaviour, build self efficacy
- skills such as relaxation
cceptance and commitment therapyL
- Emphasises acceptance and mindfulness
- CBT focuses on skills to address and control experiences and feelings.
- ACT focuses on awareness and acceptance of experiences and feelings.
- Struggling or fighting pain may cause suffering and more problems
Psychological treatments summary
- Reducing ratings of pain intensity
- Reducing distress, depression, anxiety, worry surrounding pain
- Increasing engagement with life goals and increasing function