Could sensation return after years of complete loss?

Warning: medical specialty jargon ahead

Complications of diabetes

20 million Americans live with diabetes. About 1 in 4 will experience diabetic neuropathy. For millions, their neuropathy progresses to a loss of protective sensation in their feet. This impairment leads to a cascade of falls, injuries, wounds, amputations, and early death.

Current interventions may help relieve pain, but are not intended to restore loss of sensory or motor functions. There is little expectation that protective sensation can return.

Rarely, energy-based therapies prompt the return of sensation. Without real-time recordings, such rare and unexpected events are easily dismissed.

PhotoMed Technologies builds tools that enable everyone to observe and replay events that were assumed to be rare or improbable.

Complications of surgery, scars, amputations, or reconstruction of skin

Our skin has an abundance of different sensors that provide what and where signals. Our perceptions depend on the fidelity of the signals. If the signals are corrupted, we feel pain or altered sensations. For example, the experience of “phantom” sensations from a missing limb, scar, or reconstruction of skin. For most people, the brain figures out how to correct the perceptions to reduce pain.

Pain-masking medications may block corrupted signals without restoring fidelity. Masking pain doesn’t help perception problems without a signal problem.

Testing the new algorithm

PhotoMed’s team developed its Instant Feedback System™ to make its algorithm for the Vari-Chrome® Pro more efficient. The key metric was the time to detect failure, or success.

Testing the algorithm for seemingly disparate disorders yielded unexpected responses and outcomes. The abrupt “awakening” of numb fingers or toes sparks surprise for nearly everyone.

Brenda Feels fingers - happy.jpg

How fast can normal sensation return?

Neuroscientists report mapping errors induced by amputations. For some patients, pain is reduced by using “mirror therapy” or virtual reality goggles over several to many visits. The therapies require the patient to intentionally participate with the hope that neuroplasticity might “rewire” their brain to relieve “phantom” and other apparent sources of pain and abnormal sensations. For example, touching or viewing their numb reconstructed skin give the person a creepy or nauseous feeling.

We use the term “pain” to include the experience of noxious, but “ouchless”, sensations. Impaired functions can be objectively measured, such as the loss of protective sensation.

PhotoMed’s algorithm provides the practitioner with a more efficient therapy:

  • Works passively without the patient’s intention or expectation

  • Prompts the return of sensation bilaterally after treating only one side

  • In phantom pain, sensation doesn’t return, but the perceptions are more normal

  • Two visits are enough to learn if the therapy will work or not.

Could errors in brain-maps of touch or temperature be an “ordinary” perceptual process that got stuck? Could the correction of a map be a neuroplastic event?

Observing events in real time

We thank William Conard, M.D. for being the PI of this IRB study in Sacramento, California.

Clips from PhotoMed’s real-time recordings demonstrate the what and the when of the events. Perhaps now, neuroscientists might learn the why and how of the yet unknown mechanisms.

After “reawakening” of sensation, cross-sensory feedback from vision or self-touching prompts the realignment of the perceived touch locations. Could the ordinary processes of down-regulation account for the observed phenomena?

“George” could feel being touched upon the “awakening” of both feet after being missed for 8 years. The misalignment of perceived touch locations demonstrates a curious phenomenon. Cross-sensory feedback “instantly” restores the correct map alignment. The test was made with a 5.1gm von Frey monofilament. Moments before, he was unable to feel a 19gm force.

“George” could feel being touched upon the “awakening” of both feet after being missed for 8 years. The misalignment of perceived touch locations demonstrates a curious phenomenon. Cross-sensory feedback “instantly” restores the correct map alignment. The test was made with a 5.1gm von Frey monofilament. Moments before, he was unable to feel a 19gm force.

These events can now be reproduced in your office in real time, unlike pain studies. 2 in 3 patients have little or no response. The 1 in 3 who respond are typically exhibit a startle response. A gasp, flinch, or spontaneous remark confirm that something unexpected has happened.

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+ Meet George

George had diabetes and its complications for 42 years. He enrolled in Dr. Conard's study to learn if the non-invasive therapy (now delivered via the Vari-Chrome Pro) could relieve his back pain. He didn't consider that the therapy might restore protective sensation in his feet. For 8 - 10 years, he reported that he couldn't feel his feet. He walked in while looking at the floor to maintain his balance. Not knowing about George's feet, the operator thought that his posture reflected his back pain.

George received therapy for his back and then to his left foot. George could vaguely identify heavy pressure to his left foot.

One week later, George looked at the technician and not his feet as he walked in for his second visit. He reported that he had reduced back pain, but that he didn't think that his feet had improved significantly. His wife suggested that there was improvement in both feet.

+ Treatment and testing - 2nd Visit

George's sensation was tested with von Frey monofilaments that demonstrated sensation at 19+ gms (10 grams is the threshold for protective sensation).

George was requested to NOT look at or move his feet during therapy. He complied. This was important to avoid cross-sensory feedback that might realign his perceived touch locations if sensation returned.

He received therapy to his back and to his feet. A clock started upon begining therapy to his right foot to see how long a alignment errors might persist. (Observed to continue for more than 20 minutes.)

What happened during testing?

Within 6 minutes of the first treatments to his right foot, monofilament testing found that George had achieved a protective level sensation at 5+ grams force. Real-time recordings of unexpected events may suggest follow-on studies. Could brain imaging identify where and how this ordinary (except for the years of delay) works?


You might be wondering how family members reacted to George’s sudden return of sensation that has been sleeping for years.

Could recordings from the Instant Feedback System™ help George’s friends understand changes they observed?



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