Peripheral neuropathy - can normal sensory functions resume?


This page is for health-care professionals who see patients who experience a loss of sensation or peripheral neuropathy.

More than 100 types of peripheral neuropathy have been identified, each with its own characteristic set of symptoms and prognosis. Impaired function and symptoms depend on the type of nerves that are damaged.

Current pain-masking medications and interventions provide significant pain relief for many people.

However, these methods seldom restore normal sensory functions impaired or lost to diabetes, chemotherapy or, in some cases, surgery.


What did testing with PhotoMed’s Instant Feedback System uncover?

PhotoMed’s team sponsored studies to learn which disorders might respond to its new algorithm. Inventing the therapy was the easy step.

Thanks to pain specialist anesthesiologists and neurologists, the studies welcomed patients who experienced treatment-resistant pain and impairments. The outcomes challenged notions across specialties and neuroscience.

As nerdy engineers, we could see the physiological responses in real-time recordings taken by the Instant Feedback System™.

Warming hands appeared to be “special” only because we knew about the years of malfunction. (Lighter gray is warmer.)

Figure 1 - Hands warming. The Instant Feedback System™ connects the stimulation using PhotoMed’s therapy with the warming response and outcome. Normal comfortable temperature regulation continued after three visits.

Figure 1 - Hands warming. The Instant Feedback System™ connects the stimulation using PhotoMed’s therapy with the warming response and outcome. Normal comfortable temperature regulation continued after three visits.

It looked to us like the person’s impaired functions simply snapped back to normal.

Unsurprising, our cold and numb hands innately warm when coming in from the cold.

We wondered, could a non-invasive therapy “unstick” someone’s thermostat afterr 30 years?

Of course, the stuck thermostat model isn’t very medical. PhotoMed’s team welcomes your speculations.

Surprised volunteers in IRB studies flinched, gasped, or spontaneously exclaimed at the moment when something weird happened. Sensation returned after years of profound numbness in fingers or toes.

The volunteers could correctly identify textures within minutes. They reported that they previously tried to imagine textures. Now the textures felt normal. They had dropped keys, or worse, burned their skin with hot water. Others had fallen.

PhotoMed’s advisor anesthesiologists, neurologists, and neurosurgeon were puzzled by the findings. The events seemed impossible. How could a few photons from PhotoMed’s device trigger the return of sensation that continued after therapy ended?

The advisors devised a test that might capture the event in action. It would be cool to watch. How much crazier could it get?

Can sensation return while you watch?

You’’ll just have to watch for yourself. We’ll give you the background later.

Clip 1 shows von Frey monofilament testing at 5.1 grams about 6 and 28 minutes after therapy to his right foot began. (0:47)

Clip 1 uncovered something physiologists previously predicted: cortical-map misalignment. They do experiments, such as with mosaic glasses, that scramble the visual contents. Then they remove the mosaic and watch normal vision resume.

George (not his real name) was different. He reported that his feet were numb for the past 8-10 years. Would his cortical representations of touch be scrambled upon its reawakening?

You may be wondering: how can this crazy realignment happen? We don’t know.

The backstory

George experienced diabetes for 40 years with many complications. He reported that his feet had been numb for 8+ years. He looked at his feet while walking when he arrived at his first visit. Unilateral therapy to his left foot appeared to awaken slight sensation of heavy pressure.

George arrived at his second visit, one week later, looking at the technician. George greeted him with a smile and handshake. George reported that “not much happened” during the week. His wife suggested otherwise. Von Frey monofilament testing found bilaterally improved sensation. But not to a protective level.

The technician requested George to keep his feet still and to NOT look at them until requested. George complied. (Otherwise would have ruined this experiment.) The aim was to avoid cross-sensory feedback.

The camera rolled while George received two 2-minute treatments to his left foot. The time code, added for the advisory team, starts when George began the first treatment to his right foot. Then his right foot received a second 2-minute treatment. Monofilament testing began at about 6 minutes. Therapy and intermittent testing continued until the long-anticipated event arrived at about minute 28.

It’s your turn to speculate: how can the misalignment last so long?

PhotoMed’s team would appreciate your sharing your thoughts or questions. Please use the form below.


Clip 2 provides an end-of-the-visit interview, additional testing, and what George thought about what had just happened.

Clip 2 - Interview and testing of George's (not his real name) reawakened sensation in his feet. (1:05)

What might you say to your next patients who experience a profound loss of sensation?

George is only one example of unexpected resumption of normal functions. Link to the disorder list.

Got questions or ideas to share?