Warning: technical jargon ahead
Thermal imaging provides a means for observing thermoregulatory function in real time. PhotoMed’s Instant Verification System™ lets the operator monitor possible warming responses to each 2-minute procedure. A response, or not, suggests whether to stop or adjust therapy during each visit.
Hundreds of visits and thousands of observations provided data for incrementally making the therapy more effective and efficient. Abnormal skin temperatures appeared to be linked to pain in volunteers with complex regional pain syndrome (CRPS or RSD), Raynaud’s syndrome, and diabetic neuropathy. Some volunteers reported discomforting coldness for decades.
Curiously, some complained of icy cold or burning heat irrespective of their limb temperatures. More than one volunteer asked, could their experience of coldness simply get stuck? Could their persistently cold limbs be acknowledging their feelings? What do you think?
We’re engineers, not doctors or researchers. We asked an easy question, could failure be detected quickly for people with treatment resistant pain and impaired functions? We build and broke models that might accelerate improving therapeutic efficiency. Textbooks on pain and neuroscience offered no explanations for the responses that we call the “back-to-normal” functions.
The recorded data may hold secrets waiting for others to discover. Could that be you?
The Instant Verification System™ provides an efficient method for testing speculative models for how the therapy might work. PhotoMed’s team’s “best guess” was that the therapy “worked” like a stellate ganglion block (external link) (1). The endpoints are similar with hands warmer than before and with reports of less pain.
Then one day, that model broke. Spectacularly. Was it good news or bad news? That depends…
Following are some cases that led to the model’s collapse.
Complex regional pain syndrome (CRPS or RSD)
CRPS makes the news because of its pain level and intractability frequently precipitated by a small injury or even an unknown cause.
Painfully cold hands and vascular abnormalities are frequently associated with complex regional pain syndrome (CRPS or RSD). This disorder used to be called “reflex sympathetic dystrophy” for its apparent link to the sympathetic nervous system. Thermal imaging lets the operator “see” changes in temperature to support their during-visit adjustment decisions for wavelength and other settings.
For an overview of the disorder, see this external link to NINDS description of CRPS (2)
See Table 1 and Figure 1 for the grim details in An Update on the Pathophysiology of Complex Regional Pain Syndrome by Stephen Bruehl, PhD. external link to the article.(3) Could all those factors resolve after a response to a few photons?
PhotoMed’s therapy isn’t the first to achieve that outcome. Infrared therapy began to help a few people in the 1990s. The IR therapy was too inefficient for commercial success for its required knowledge, treating skills, and clinic time.
PhotoMed’s team and its pain-specialist advisors set out to solve the efficiency problem for addressing CRPS and diabetic neuropathy. The Triple 2 Algorithm began by recording data when it took 5 visits to detect probable failure of the therapy. That’s a lot of visits for someone with horrible pain. We especially thank the volunteers who left with their pain unabated for the data that they contributed.
For many with this disorder, the blood circulation in affected limbs might drop low enough to cause changes in the bone and skin. However, circulation doesn’t appear to nearly stop as may occur with Raynaud’s syndrome. Wasner examined different cases of initial hand temperatures. His studies cycled the patient’s body temperatures to study the vascular responses. None of the patients improved function or reported pain relief.
For an overview of vascular abnormalities, see this external link to a paper(4) by Gunner Wasner, et al in 2001.
PhotoMed’s team hasn’t found predictions or proposed mechanisms for the observed warming responses in textbooks on pain or neuroscience. Even a complete return to normal function does not solve all of the person’s problems, such as the loss of job, friends, and community.
Key Observations for Figure 2
The constant offset (parallel lines) in left/right hand temperatures provides clues about innate functions. The coordinated warming suggests that the controlling command occurs deep in the brain before signals make their left-right split. Could the precision of the offset across a large dynamic range suggest that all the sensing and control mechanisms are all working correctly? Except for the initial temperature and unremitting pain?
From thermal imagining recordings:
The temperatures during the first 10 minutes remain stable without either hand becoming colder.
The temperatures appear to be synchronized throughout low and high rates of blood circulation.
The single overshoot suggests a systematic means to achieve its new state in the minimum time. Isn’t that cool?
Without knowing the “before” state, could the warming response look “normal”?
Could the magnitude of the warming response be a function of the therapy or the body? Could the starting temperature affect the apparent magnitude of the response?
Raynaud’s syndrome reduces blood circulation in affected fingers or limbs. The loss can be so severe that the fingers turn white, blue, or red and may lead to gangrene. The blood circulation does not appear to be regulated to maintain a low temperature as with typical CRPS. Link to External Information (5)
PhotoMed’s Triple 2 Algorithm suggests that therapy be applied to points about the neck. Our neurologist advisor looks for a pupillary response to tell her when the patient begins to respond. The low initial temperatures of the affected extremities and low blood circulation delays the observation of a warming response.
“Sarah’s” middle finger occasionally went cold and turned white. She reported that the problem usually occurred after using gardening clippers.
In Figure 3, Sarah received four 2-minute applications of variable wavelength light. Her affected finger continued to cool and then began to slowly warm. The cold finger’s temperature dropped below 18 deg C which is represented by the blue color. At about 20 seconds into the video, you can observe lightening gray on the sides of her cold finger which indicates warming from increasing blood circulation.
Sarah’s fingers normalized after about 30 minutes. She later reported that she had had no incidents for 3 years.
Years before this visit, “Katherine” underwent a sympathectomy to force her cold left hand to warm aimed to relieve her CRPS pain. Over several years, her hand turned cold and painful again. She experienced periods of abnormal blood circulation, sometimes in half of her face. Link to External Page (6)
Then her whole body became painful. Nothing helped. Katherine decided to take the risk for being placed in an experimental coma for a week in Germany. The coma provided a few months of relief. She volunteered in a PhotoMed study to learn if it might provide relief. The therapy provided relief from her painful coldness feeling in both of her hands despite that her left hand did not warm.
A procedure called a sympathectomy killed the nerve that controls thermoregulation in her left hand such that the blood circulation could not be increased. After the sympathectomy, her hand became warmer with less pain. After a few years, it reverted to cold and painful.
During therapy at her first visit, her left hand continued to cool during the therapy and visit. Her right hand appeared to respond by warming after her second application of PhotoMed’s therapy.
Katherine reported that her pain and feeling of coldness resolved in both hands during the visit. Could the feeling of “coldness” be disconnected from the actual temperature?
Katherine’s pain remained low for more than 3 years after her first PhotoMed’s therapy with the help of annual “boosters”.
Stellate ganglion block vs. PhotoMed’s therapy
The stellate ganglion block (SGB) is aimed to provide temporary relief from certain types of pain, such as CRPS, that affect thermoregulation in a single limb. The block shuts off thermoregulation in one hand by anesthetizing the nerve that controls thermoregulation in the limb. The block is used diagnostically to test whether forced warming might relieve pain. If the procedure works, then the pain specialist may consider performing a sympathectomy to kill the nerve.
For nearly 10 years, PhotoMed’s team used the SGB as a model for how its therapy might work. This was based upon the comparison of warming effects. Both were thought to prompt the warming. The differences came later as the benefit of the SGB typically wears off after a week or two. The benefits from PhotoMed’s therapy continued, now for years, for some patients. The return-to-normal functions outcome from PhotoMed’s therapy has no expected expiration date.
Key observations from Figure 5 that led to the collapse of PhotoMed’s model for the therapy
The mechanisms for the warming are distinctly different:
The non-invasive therapy prompts the bilateral return of normal thermoregulatory controls. (A-B-C)
The invasive intervention forces a unilateral loss of normal thermoregulatory controls (D-E) to abnormally increase blood circulation and warming of the hand.
The magnitude of the responses appeared astoundingly large at 10 degrees C. We later realized that the magnitude is limited by the initial and maximum available temperatures.
It was the prompts vs. forces observation that collapsed the comparative model. Later, we noticed that the bilateral vs. unilateral responses that could have been observed from the very first tests of PhotoMed’s therapy.
A caution for a diagnostic stellate ganglion block (SGB)
Both the SGB and PhotoMed’s therapy aim for a warming response. People with a variant of CRPS called “hot CRPS” may be adversely affected by a diagnostic SGB.
Thermal imaging, see Figure 6, helps the practitioner distinguish hot vs. cold variants of CRPS:
“Cold” typically shows a cooling trend toward the finger tips
“Hot” typically shows a warming trend toward the finger tips.
Red and lighter gray represent warmer temperatures.
Detection of the “hot” variant CRPS is an important aspect of PhotoMed’s Triple 2 Algorithm. The operator applies a “mini” procedure and waits about 1 minute for the patient to notice if their hand(s) are getting even warmer. Repetitions of the “mini” therapy during different visits sometimes prompts the CRPS to switch to the “cold” variant. Then, the “cold” steps in the algorithm may prompt the return to normal function.
(3) https://anesthesiology.pubs.asahq.org/article.aspx?articleid=1933227 Stephen Bruehl; An Update on the Pathophysiology of Complex Regional Pain Syndrome. Anesthesiology 2010;113(3):713-725. doi: 10.1097/ALN.0b013e3181e3db38.
(4) https://academic.oup.com/brain/article/124/3/587/334375 Gunnar Wasner, Jörn Schattschneider, Klaus Heckmann, Christoph Maier, Ralf Baron, Vascular abnormalities in reflex sympathetic dystrophy (CRPS I): mechanisms and diagnostic value, Brain, Volume 124, Issue 3, March 2001, Pages 587–599, https://doi.org/10.1093/brain/124.3.587
(6) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2758836/ Groeneweg G, Huygen FJ, Coderre TJ, Zijlstra FJ. Regulation of peripheral blood flow in complex regional pain syndrome: clinical implication for symptomatic relief and pain management. BMC Musculoskelet Disord. 2009;10:116. Published 2009 Sep 23. doi:10.1186/1471-2474-10-116