The Brain in Pain

Cortical contributions to Complex Regional Pain Syndrome

Dr Janet Bultitude

Overview

1. Cognitive and cortical changes in CRPS

2. Possible role in clinical symptoms

3. Implications for treatment

4. Proposed mechanisms

Complex Regional Pain Syndrome

Complex Regional Pain Syndrome

“As the pain increases, the general sympathy becomes more marked. The temper changes and grows irritable, the face becomes anxious, and has a look of weariness and suffering. The sleep is restless, and the constitutional condition, reacting on the wounded limb, exasperates the hyperaesthetic state, so that the rattling of a newspaper, a breath of air…the vibrations caused by a military band, or the shock of the feet in walking, gives rise to increase of pain.” Silas Weir Mitchel, 1864

Distorted body representation

Lewis et al., 2010, Pain

Distorted body representation

• “I feel disgust, I know it sounds a very strong word to use but I’m disgusted that my arm is this way.”

• “It was just like this foreign body you were carrying around with you cause it didn’t feel like it was part of you.”

Lewis et al., 2007, Pain

Distorted body representation

• Difficulty locating / moving the limb unless directly looking at it

• Difficulty identifying fingers from touch• Referred pain, or pain when viewing an

object approaching the limb• Movement-induced pain greater when

viewing hand through magnifying lens, less when viewing hand through minimising lens.

Cortical reorganisation

Maihöfner et al., 2004, Neurology

Cortical reorganisation

Gieteling et al., 2008, Pain

Mechanisms of CRPS

1999, The Lancet

“When our senses present us with discordant information, such as when our eyes give our brain information that does not agree with our senses of body position, balance, and equilibrium, we feel nausea. Less familiar is the notion that discordance between awareness of motor intention, muscle and joint proprioception, and vision may result in our feeling pain.”

Poke your eye

Predictive signal

True sensory outcome

Predictive signal

True sensory outcome

? ? ?

Implications for treatment

Predictive signal

True sensory outcome

? ? ? Healthy handrepresentation

Predictive signal

True sensory outcome

Healthy handrepresentation

Predictive signal

True sensory outcome

? ? ?

Prism adaptation

Prism adaptation

Sumitani et al., 2007, Neurology

Prism adaptation

Transcranial Direct Current Stimulation

Transcranial Direct Current Stimulation

Antal et al., 2010; The Clinical Journal of Pain

Proposed mechanisms

Immobilization-driven reorganisation?

Immobilized IF Healthy IF

Lissek et al., 2004, Current Biology

Direct immune mechanisms?

Overview

1. Cognitive and cortical changes in CRPS

2. Possible role in clinical symptoms

3. Implications for treatment

4. Proposed mechanisms

Take-home messages

Cortical origins to pain

≠It’s all just in your head

Take-home messages

• Importance of:– Early recognition– Aggressive intervention– Multiple simultaneous approaches– Cognitively- and cortically-targeted treatments

Now recruiting

We are looking for volunteers with CRPS for a study investigating two potential treatments that target cognitive and cortical changes.

Interested patients can contact me at crps@fmrib.ox.ac.uk

or jbultitude@fmrib.ox.ac.uk