Restoration of Sensation May Lead to Reduced Phantom Limb Pain in Amputees

Dear Pain Matters blog readers,

Biomedical engineers at the Case Western Reserve University, Cleveland, Ohio, have (unwittingly) reduced/eliminated phantom limb pain in 2 amputees with severe phantom limb pain while also restoring sensation across both hands via novel ‘prosthetic system’ treatment.

prosthetic-feat-1.jpg

Source:   Case Western Reserve University, Cleveland, Ohio

http://engineering.case.edu/Tyler-prosthetic-sensation

Prior to prosthetic system treatment to help restore sensation, both men were unable to feel their hands.  Both men had also suffered from phantom limb pain. 

Post-prosthetic system treatment, both patients gradually began to feel familiar sensations again.

Both patients were also able to ‘feel’ their hands for the first time since their accidents, and this helped them control their prosthetic hands better.

Restoration of Sensation and Possible Reduction of Phantom Limb Pain via Novel Prosthetic System Treatment:

Electrode cuffs (2-3) that encircle major nerve bundles were surgically implanted into both patients’ arms.  These electrode cuffs enabled the patients to feel 16-19 distinct ‘contact points’.

The sensory nerves were stimulated via unique and changing patterns and intensities of electrical signals that were sent to the 16-19 distinct ‘contact points’ on the electrode cuffs.  Different signal patterns (transmitted to the electrode cuffs via the prosthetic system) are interpreted as different feelings by the brain.  This can lead to the restoration of certain sensations.

For example, certain patterns and intensities of electric signals may evoke the feeling of cotton, while other electrical signal patterns may feel like ‘water running across the back of a hand’, sandpaper, a smooth surface or even a ridged surface.

An unexpected positive outcome from this prosthetic system treatment was that, after 2 years of testing, the phantom limb pain was gone.

The 2 Patients:

(1) The first patient, Mr Spetic, lost his right hand in an industrial accident 4 years earlier.  He suffered phantom limb pain since the accident.  Quoting Mr Spetic (in the video):

‘The way I described it was:   My hand was in a vice and crushed, and it kept on going and going.’

Following experimental prosthetic system treatment whereby a computer algorithm sent certain patterns of electric signals into the nerves, Mr Spetic said that his phantom limb pain subsided.  Quoting Mr Septic (in the video):

‘Just about, I’d say, 90-95% gone.’

(2) The second patient, Mr Vonderhuevel, who had phantom limb pain following the loss of his right hand and part of his forearm in an accident, said that his phantom limb pain was ‘nearly gone following experimental prosthetic system treatment.

Credit:   Case Western Reserve University, Cleveland, Ohio 

Summary:

Targeted restoration of sensation via prosthetic system treatment may lead to significant reduction, and even elimination, of phantom limb pain for some phantom limb pain sufferers.  This offers hope to amputees with pain.

Sabina Walker

REFERENCES

(1) Amputees discern familiar sensations across prosthetic hand

http://engineering.case.edu/Tyler-prosthetic-sensation

(2) Prosthetic hands endowed with a sense of touch; Elizabeth Pennisi; 8 October, 2014

http://www.sciencemag.org/news/2014/10/prosthetic-hands-endowed-sense-touch

(3) Thomson, H.

Once more with feeling

New Scientist, Volume 224, Issue 2991, 18 October 2014, Pages 8–9

 

 

 

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