Lecture - Phantom Limb Pain

Question 1

Phantom limb pain:

1. What is it?
2. What happens overtime?
3. Whereabouts is the pain and how often?
4. What words do people use to describe it?

Answer 1

1. A vivid sensation of something that doesn’t exist - curious syndrome. It’s like chronic pain
   -Yes it fulfils the criteria of pain lasting longer than
   the injury might suggest, but is a very special case
2. It subsides often by ‘telescoping’
   - The phantom slips inwards (‘telescopes’) towards body like hand will start ot feel like it’s on shoulder after a while (aka moves from being where it is to feeling like it’s getting closer)
3. Often distal (fingers, toes, ankles, palm etc). It is often intermittent
4. Shooting, stabbing, boring, squeezing, throbbing and burning - sounds like neuropathic

Question 2

Sensory aspects:

So there is a continuum from the sensation being a vague sense of limb to a very specific/vivid sensation

What sort of sensations can it be?

Answer 2

􀀁 Touch/Pressure
􀀁 Warmth/Cold
􀀁 Itch
􀀁 Wetness
􀀁 And of course, Pain in all it’s forms (burning, cramping, etc).

Question 3

What’s behind the phantom limb thing?

Answer 3

• Peripheral, Central and Psychological factors
  􀀁
• Fundamental neural processes of body/self
  perception lays the foundation
  􀀁
• Many factors are involved, including learning and
  ‘pain memory’ e.g., amputated limb with a persistent painful condition (e.g., a corn), continued perception of corn in phantom limb

-Gives us clues to how the brain operates normally
on sensory input

Question 4

Can we block the sensation by doing something beforehand?

Answer 4

Not really

Question 5

What does phantom limb pain have to do with the somatosensory cortex?

Answer 5

From last year, the AP can still go through and to the specific part of the cortex where the path goes to.

Question 6

What internal and external factor modulate phantom limb pain?

Answer 6

Internal factors:
􀀁 Genetic predisposition
􀀁 Anxiety/emotional distress
􀀁 Attention/distraction
􀀁 Other disease

External factors:
􀀁 Weather change
􀀁 Touching the stump
􀀁 Use of prosthesis
􀀁 Rehabilitation
􀀁 Treatment

Question 7

How can you help those experiencing pain?

1. Do painkillers work?
2. Surgical, medical and non-medical treatments - promising or nah?
3. Are there clear evidence based guidelines?

Answer 7

1. Not very well
2. Not really
3. No

Question 8

There is consistent evidence of pain reduction for illusion based treatment - what three things?

What’s their mechanism?

Answer 8

1. Illusion of existence of real body part
2. Mirror therapy
   - like put a mirror between legs and it seems like you have your left leg.
3. Body resizing
   - In virtual realtily, they can alter sensory input or whatever and make it seem like your phantom limb is tiny and if it is tiny then your pain will be tiny

If you make it blue then will change pain sensation and won’t feel like burning more maybe?

Mechanism: neural plasticity.
-􀀁 Phantom pain leads to changes in cortical
representation of the affected limb and phantom
limb pain
- Magnitude of changes is greater when pain persists
- Mirror therapy can reverse cortical changes

Question 9

Summary:

1. What does phantom limb pain provide evidence for?
2. Neural _____ can be observed
3. There are three changes that are observable - what are they?
4. Pharmacological treatment is largely ineffective but…..

Answer 9

1. 􀀁 Phantom limb pain provides evidence for neural pain mechanisms
2. Neural plasticity can be observed
3. There are peripheral, spinal and brain changes that are observable
4. Pharmacological treatment is largely ineffective but several
   treatments are available based on cortical plasticity