This start-up hopes their efforts to take TENS units from a bulky, complicated, marginally effective technology to a slick, app-enabled wearable will change the way we treat chronic pain.
by John Tyler Allen
It was still early one fall evening in 2011 when Shaun Rahimi lay alone in his dorm room, afraid to move for fear he’d stoke the neuropathic flame that burned from his neck to his feet. At thirteen he had developed Scheuermann’s disease, a skeletal disorder that caused several of his thoracic vertebrae to form into a wedge shape and force his spine into an unnatural forward curve. Because sudden movements meant worsening his already unbearable pain, he would often resign himself to immobility, a tacit acceptance that he was a prisoner of his own nervous system.
As Rahimi lay in his bed that night, the open window next to him let in the music and the noise from a fraternity party down the street. It occurred to him that this was his life and his youth; this was the closest he would come to the college experience. Bitterness followed. e partygoers’ voices were alive with a happiness he would never know, and he resented them for it. He shifted in his bed and another jolt of pain lit up his spine. is is when his thoughts began to border on delusion, he said. He began to mash at one of his wrists, desperate to turn o his pain. He could almost see a button there, and if he only pressed it, he could calm the fire in his neck and back. And what if the debilitating carpal tunnel in his arms suddenly vanished? What if he regained his hands? It was absurd, he knew, but the thought wouldn’t leave him. What if something as simple as a button, right here on his wrist, could stop all of this?
Now, four years later, Rahimi, a twenty-six-year- old biomedical engineer and entrepreneur from San Francisco, is hoping to soon bring to market a wearable device engineered to do just that. e unit ad- ministers transcutaneous electric nerve stimulation (TENS), a low-grade electrical current that can be manipulated to inhibit the brain’s ability to perceive pain signals from virtually any point on the body. Professional units are roughly the size of a thick hardcover book and allow a physician to fine-tune the pulse rate, pulse width, and amplitude of a current until it achieves a strong but comfortable level of motor nerve stimulation. Rahimi’s device is the size of a wristwatch and not only provides “the same features and benefits” as the most powerful professional units on the market, he said, but it does so by self-calibrating at the touch of a single button.
Electrotherapy dates to ancient Rome and the first modern, wearable TENS unit was patented in 1974. Since then, and despite the therapy’s longevity, poorly designed studies (patient non-compliance, lack of placebo, inadequate sample sizes, the misunderstanding of dosage requirements) have reinforced a perception of TENS as a therapy de ned by inconclusiveness. A recent Cochrane review of TENS studies evaluated nineteen randomized controlled trials and found only six studies that could contribute meaningful data. The best the authors could muster: “We concluded that TENS may reduce the intensity of acute pain in some patients but the quality of evidence was weak.” Rahimi’s belief in the therapy’s potential remains unfettered. “I understand that perspective because it’s a common one, especially when considering the need for evidence-based medicine,” he was quick to point out. “But I think it’s misleading.” Small sample sizes and underpowered devices don’t negate the fact that the majority of TENS studies are positive, he said. More formative, though, was that time when Rahimi lived with mind-altering pain and, after a year and a half of trial and error with eight different prescription pain killers – “I don’t remember my third year of college,” he said – a physician attached a TENS unit to his neck and his pain disappeared. Perhaps this makes it less surprising that Rahimi has given his device the rather high-achieving moniker, CŪR. Rahimi, who is the CEO of CŪR, Inc., developed the first prototype with Kevin McCullough, co- founder and chief technical officer, and Earl Vickers, a digital signal processing engineer. e main innovation lies within a basic closed feedback loop. As CŪR self-modulates its current, an accelerometer and bioimpedance sensor detect both the unit’s place on the body and specific movements within the muscle that indicate motor nerve stimulation.
Within a few seconds, the device can calibrate itself to the optimal strong but comfortable level. And if the wearer wants more control, the settings can be further customized via a smartphone app that pairs with and controls the unit. CŪR has also been fitted with an advanced waveform generator – a particular point of pride for both Rahimi and McCullough – which enables it to produce a “new type” of waveform that will “affect the nerve in a more compelling way,” Rahimi said. He declined to elaborate.
The simplicity of the design, the “form factor,” as Rahimi and McCullough kept calling it, was ap- approached with as much purpose as the technology it holds, and it stands alone as its own feat. CŪR’s electronics are housed in a sleek plastic square the size of a watch face, which magnetically attaches to the electrodes in a two-inch-by-five-inch reusable gel patch. In past interviews and in online start-up forums, Rahimi introduced CŪR as “a Band-Aid for pain;” the influence on the design and the ethos are obvious. “You can put it on, go to the bathroom, hang out with your friends, go to a concert, whatever you have to do, and not think about it,” Rahimi said. “ The form factor is a big part of it. at’s what drives adherence to TENS treatments.”
“ There are small TENS units you can put in your pocket or clip on your belt,” Dr. Joanna Katzman, director of the University of New Mexico Pain Center and president of the American Academy of Pain Management, said. “But you can’t go to a gym class so easily, or run three miles.” CŪR’s design and function could inspire greater compliance in patients prescribed TENS to treat arthritis, musculoskeletal pain, neuropathic, and acute post-operative pain. However, she added, “patients with moderate pain probably aren’t doing that high, high level of activity.”
Katzman also stressed the complexities of pain, saying any implications that pain management can be reduced to a single device are unrealistic. “Most patients who have chronic, non-cancer pain usually need a multi-modal approach,” she said. “It’s rarely just one pill, just one device like a TENS unit, just one thing that is the answer.” She was optimistic about the potential for CŪR’s size and portability to reduce reliance on medications: “We’re always looking for integrative approaches to pain management that don’t include pharmacotherapy...(es-pecially) in this era of opioid overdose and risk of opioid dependence and addiction.”
Dr. John Garzione, a physical therapist and electrotherapy expert currently studying the effects various treatments have on the nervous system, says, “Some people respond better to one type of stimulation than another.” And some can’t tolerate a TENS current strong enough to incite the motor nerve or the resulting muscle contraction. To this end, CŪR’s ability to self-modulate to a strong but tolerable level could demonstrate value, he said. But he cautioned against lapsing into unsubstantiated hype. For instance, claims of superior waveforms were popular thirty years ago, soon after the arrival of wearable TENS units. “ The research has not, at this point, said that one waveform is superior to another,” he said, alluding to a 2007 study by the Pain Research Program at the University of Iowa that found “differences in waveform characteristics do not affect the anti-hyperalgesia produced by TENS.” “(Research) is all we can really go on as professionals,” Garzione said. “What does the research show us?”
Both Garzione and Katzman reiterated this warning. e device has yet to be cleared by the FDA (Rahimi’s “the same features and benefits” comment is the most concrete claim the FDA will allow him to make) or endure a single clinical trial. Rahimi welcomes the burden of proving CŪR’s effectiveness. “We want to build a brand and a company that has a strong scientific basis,” he said. “Not only so consumers, but especially physicians, can appreciate the data we have.” To this end, the founders are currently designing studies in coordination with two well-known medical centers – one in the San Francisco area and one in the Midwest – to be launched in the next year.
In the past year, CŪR’s founders have been criticized for using a crowdfunding campaign to market and take orders on a device that lacks FDA approval. In a statement addressing the allegations, Rahimi countered that the fundraising was “designed to support the continuing development operations,” and that the product would only ship a er FDA approval. McCullough added that, before the campaign, the CŪR founders submitted their verbiage for rigorous legal vetting by FDA regulatory experts and, to date, CŪR’s messaging has been sufficiently compliant.
Still, the website for Thimble Bioelectronics – from which CŪR, Inc was born – currently adver- tises for a wearable device that will “heal back pain as quickly and easily as healing a cut.” And the CŪR website features what amounts to a two-minute testimonial advertisement in which a TENS unit is attached to chronic pain sufferers who, as soon as the machine is turned on, sigh in relief and revelation. An emotional piano soundtrack swells in the background and, through a series of cross cuts, we’re implicitly told CŪR will see chronic pain “vanish,” leading to “a life without pain.” The video’s implications are “very bold claims,” one pain management physician said (she asked that her name not be given). “Patients come to us and they want to (their pain intensity) go from an eight over ten to a zero over ten. If we can lower the pain by fifty percent, that’s considered extremely good. But sometimes getting to zero, once the patient has gone down the road of chronic pain, might be unrealistic... They’re very confident that this device will help people completely.” Dr. Garzione also voiced frustration with the claims in CŪR’s promotional material. “As professionals,” he said. “We really have to protect people from (unsubstantiated claims).”
“There’s a lot of science in the past twenty years that’s been developed around TENS and which settings are more effective for a given user,” Rahimi said. “But the technology has not caught up to that science at all.” McCullough elaborated: “We can make miniaturized electronics, we have better sensing technology – we can really make some very smart devices. But when it comes to treating pain, there haven’t been significant companies to step forward and make those innovations.” Garzione admitted that this was one aspect of CŪR that was especially intriguing. “We have seen innovation in electromedicine go, basically, down the tubes,” he said. And later he added, “I’m excited about any innovation...If this really is truly effective, I’m excited about it... I really hope it does what they say.”
For Rahimi, the TENS perception, the technology, the friction of introducing a new product into a noisy market, are all secondary to the pain. “As long as the technology (is) somewhat feasible from the start,” he said. “You (can) build things people don’t expect to be possible. Questioning what’s possible or not doesn’t really make as much sense as asking, How important is the problem?”