Phantom Limb Pain

yardbellAI and Robotics

Nov 14, 2013 (3 years and 5 months ago)

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Phantom Limb Pain


Severe injury leading to amputation



Pain sensations experienced not
necessarily cease after amputation



Most (in excess of two
-
thirds) experienced
by patients who have lost a limb at least
occasionally

What is the “Phantom Limb”


VS Ramachandran begin at 3:15
-
minutes

http://www.youtube.com/watch?v=sq6u4XVrr58&feature=video_response

What is the Phantom Limb
phenomenon?


After amputation still feels like limb is there, attached to
body, moving appropriately with other body parts



Can also happen when born without a limb or when
paralyzed?!



Constant pain for some



Not all phantom limb experience is painful


feel gesturing, itches, twitch or even attempts to pick things up



Not gender biased

What is the Phantom Limb
phenomenon?


Phantom arms will swing while a woman walks



Phantom fingers will grasp for a cup as a man
aims his stump toward the table



A man reported falling out of bed in the morning
when he tried to bear weight on his phantom leg




Sensation of a watch or ring can often be felt


The Process of Neural (cortical)
“plasticity”


When a limb is lost, the cells of the area in the
somatosensory cortex that responded to the
missing limb begin to respond to other stimuli.



Newly recruited cells begin to respond to the
body part represented by the new reorganization.


Neural/cortical plasticity


Encroachment actually takes place on either
side of the deafferented location in the brain
so that the two receptive fields actually
enlarge to fill in the area.



Stimulation to corresponding body part
which is encroaching on deafferented
location results in feeling sensations in your
phantom limb.

One theory about why pain is experienced


Ramachandran et. al. (1993; 2000)



Cortical reorganization correlates with the pain felt in
the phantom limb



Phantom limb sensations are due to the “cross
-
wiring” of the somatosensory cortex


Sensory “confusion” experienced as pain


Pain results from “mis
-
match” between an
absence

of
an
anticipated

motor output historically paired with the
sensory information processed in the somatosensory
cortex

Psychological

Interventions

Therapy: re
-
create a
match

between sensory experience
and motor output to resolve
the mis
-
match confusion


Medication


Psychotherapy


Behavioral Therapy


Hypnosis


Ramachandran Mirror Box



Classic mirror treatment phantom
limb pain
-

Ramachandran (1993)


If the patient gets visual feedback that the phantom is obeying
the brain’s commands, the learned paralysis is sometimes
unlearned.


Mirror imaging of limbs using a mirror box

Classic mirror treatment phantom
limb pain
-

Ramachandran (1993)


If the patient gets visual feedback that the phantom is obeying
the brain’s commands, the learned paralysis is sometimes
unlearned.


Mirror imaging of limbs using a mirror box

“Look into side of the
mirror so that you see the
reflection of your intact
hand superimposed on the
felt location of your
phantom hand.”


“Then try to make
symmetrical motions using
both hands (e.g.,
conducting an orchestra).”

Classic mirror treatment phantom
limb pain
-

Ramachandran (1993)


This method has positive therapeutic
value for some patients

In some patients, the
procedure animates the
phantom as never
before, allowing it to
“move.” The sudden
sense of voluntary
control and movement
reduces and sometimes
permanently removes
phantom pain.

Psychological

Interventions



Medication


Psychotherapy


Behavioral Therapy


Hypnosis


Ramachandran Mirror Box


Virtual Reality training


Virtual Reality





-
developed off of Mirror Box

What is the “Phantom Limb”


http://www.youtube.com/watch?v=PpEpj
-
JgGDI&feature=related

http://www.youtube.com/watch?v=jNIqyyypojg

Soldiers get virtual reality therapy for burn
pain

60
-
Minutes “Brain Power”


http://www.cbsnews.com/video/watch/?id=4
564186n