Category Archives: Restoration of Sensation

Restoration of Tactile Performance in the Affected Hand via High-Frequency Repetitive Sensory Stimulation May Lead to Reduced Pain in some CRPS Patients

Dear Pain Matters blog readers,

Prof. Dr. Christoph Maier and team recently found that restoration of sensation (i.e. tactile performance) in the affected hand via high-frequency repetitive sensory stimulation (HF-rSS) may result in significantly decreased pain in patients with complex regional pain syndrome (CRPS).

Specifically, the Current Pain Intensity decreased by more than 30% in 4 of 16 CRPS patients who underwent HF-rSS of the CRPS-affected hand for 45 minutes a day for 5 consecutive days only.

Significantly improved tactile discrimination in the CRPS-affected hand also occurred in all 16 CRPS patients following HF-rSS intervention.

There were no medication changes in the 16 CRPS patients who had HF-rSS  intervention.


Prof. Dr. Christoph Maier

Featured Image and Above Image:


The Study Including Results:

The study involved 20 CRPS patients, 16 who underwent HF-rSS treatment for 45 minutes a day for 5 consecutive days, while another 4 had low-frequency repetitive sensory stimulation.

Targeted electrical stimulation was applied to all the fingertips in the CRPS-affected hand by a custom-made hand pad.

Four (4) of 16 enjoyed significant pain reduction (more than 30% pain reduction) following HF-rSS treatment for 5 consecutive days.  

According to Table 1 in the study by Maier and his team, the following 4 patients had significantly reduced pain intensities immediately following HF-rSS treatment for 5 days (compared to their average pain levels, 4 weeks preceding this treatment):

  • Patient #2 (46 years, male; CRPS, right hand, duration = 5 months; fracture/surgery)
    • Average Pain (prior) = 7
    • Current Pain (after) = 0
  • Patient #8 (58 years, male; CRPS, left hand, duration = 4 months; surgery)
    • Average Pain (prior) = 6
    • Current Pain (after) = 1
  • Patient #9 (60 years, female; CRPS, left hand, duration = 2 months; fracture/surgery)
    • Average Pain (prior) = 10
    • Current Pain (after) = 1
  • Patient #15 (60 years, male; CRPS, right hand, duration = 8 months; fracture/surgery)
    • Average Pain (prior) = 9
    • Current Pain (after) = 2

The same Table 1 also listed 2 additional patients with significantly reduced pain following low-frequency repetitive sensory stimulation:

  • Patient #19 (58 years, female; CRPS, right hand, duration = 9 months; surgery)
    • Average Pain (prior) = 7
    • Current Pain (after) = 3
  • Patient #20 (58 years, male; CRPS, left hand, duration = 4 months; fracture/surgery)
    • Average Pain (prior) = 5
    • Current Pain (after) = 0

It is not known how long these pain reductions lasted.


High-frequency repetitive sensory stimulation (HF-rSS) to all fingertips in the CRPS-affected hand:

  • to improve sensory loss (i.e. restore sensation including tactile performance); and/or
  • to reduce pain in the CRPS-affected hand

may be a useful non-pharmacological (add-on) treatment for some CRPS sufferers.

Maier and his colleagues conceded that while CRPS patients were only tested for 5 consecutive days, greater pain reductions for more CRPS patients may have resulted had the testing period been significantly longer.

This is a fair comment given that a study involving 2 amputees with phantom limb pain resulted in restoration of sensation as well as nil phantom limb pain following ‘prosthetic system treatment’ for (up to) 2 years.

Sabina Walker

“Sedare dolorem divinum opus est”
“It is divine to alleviate pain”

Galen, 130-200 C.E.


(1) David M, Dinse HR, Mainka T, Tegenthoff M, Maier C.

High-Frequency Repetitive Sensory Stimulation as Intervention to Improve Sensory Loss in Patients with Complex Regional Pain Syndrome I.

Frontiers in Neurology. 2015;6:242.


(2) High Frequency Stimulation in Pain Medicine

Kalus, Annegret

Ruhr-University Bochum (No. 163 – 20.11.2015)

(3) Hochfrequente Stimulation Hilft Menschen Mit Schmerzsyndrom

Schubert, Christine

CRPS Bayern Morbus Sudeck Selbsthilfegruppe (19.2.2016)

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.


Source:   Case Western Reserve University, Cleveland, Ohio

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 


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


(1) Amputees discern familiar sensations across prosthetic hand

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

(3) Thomson, H.

Once more with feeling

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