3.3.1 Types and theories of pain

Define pain.

Pain is not only an unpleasant experience, but also acts as a signal to let us know that whatever we are doing is potentially damaging and we should stop.

Types of pain + explanations.

Acute pain can be severe but comes one quickly and lasts for a relatively short

period of time and is in a specific location on the body with an identifiable source,

for example injury or illness

Chronic pain lasts for a relatively long period of time (at least a month) and is

resistant to treatment, and is likely to be the result of long-term behavioural factors

such as physical exertion, or chronic illnesses such as cancer

Muscoskeletal pain is a form of chronic pain that occurs in the muscles, bones,

ligaments and tendons in the body

Phantom limb pain (PLP) is a type of pain experienced by people who lose a limb. Even though the arm or leg is no longer there, the individual still experiences pain as

coming from that area

What is Mirror treatment in PLP?

Mirror treatment is a way of treating phantom limb pain, and it works by placing the

remaining limb (for e.g. arm) into a box, with a mirror down the middle, so it looks to the

patient as if they have two intact arms. The patient will then take part in a range of arm movement exercises with the actual limb, and look at the reflection in the mirror, and psychologically treat the discomfort experienced in the phantom limb.

Who was the participant in MacLachlan et al. (2004) and what condition did he have?

Alan, a 32-year-old man who experienced phantom limb pain after a life-saving leg amputation at the hip.

What treatments did Alan (MacLachlan et al) initially try, and were they effective?

He tried pain medication and TENS treatment, but neither reduced his phantom limb pain.

Q: What is mirror therapy and how was it applied in Alan’s case?

A: Mirror therapy involved performing 10 exercises (like bending the leg, moving toes) in front of a mirror, initially with a physiotherapist, then independently, up to four times a day for three weeks.

How did Alan’s phantom pain, stump pain, and control over the phantom limb change?

: Phantom pain dropped from 5–9 to 0, stump pain from 0–2 to 1, and sense of control over the phantom limb increased from 0–3% to 25–30%.

Did Alan’s perception of his phantom leg change completely?

The phantom leg remained shorter in his mind, but with effort, he could ‘straighten it out.’

What does the Specificity Theory of pain (Von Frey, 1895) propose?

There are specialized pain receptors that send signals to the brain, which then processes the sensation and triggers a motor response to reduce harm.

Give an example of Specificity Theory in everyday life.

ouching something hot triggers pain receptors in the hand, the brain processes the pain, and signals the hand to move away.

What is the main idea of the Gate Control Theory (Melzack & Wall, 1965)?

The spinal cord has a “gate” in the dorsal horn that controls whether pain signals reach the brain, influenced by the activity of small and large nerve fibres.

How do small and large nerve fibres affect pain perception according to Gate Control Theory?

Small fibres transmit pain; large fibres transmit touch. More large fibre activity closes the gate, reducing pain; more small fibre activity opens the gate, increasing pain.

Why do we rub an area after getting hurt?

Rubbing stimulates touch via large nerve fibres, which helps close the gate in the spinal cord and reduces the perception of pain.