I spoke at length last week with Dr. Rhodes about ways that we could better determine the effectiveness for DMD of his VECTTOR electrical stimulation system, which Dr. Rhodes says stimulates acupuncture points, reflexology points and free nerve endings. Dr. Rhodes was very up front about the fact that he isn’t a scientist and isn’t an expert on DMD and his actual professional training is in podiatry. He has supplied his VECTTOR machine to 36 families with muscular dystrophy—he didn’t specify how many were DMD, but I got the impression that the majority of them went to families with sons with DMD. The machines cost around $4000 each and Dr. Rhodes owns the company that makes them. He does offer to buy back the machine from any family that is not satisfied with the results (I didn’t ask him if any had ever been returned).
His hypothesis for how the machine works is that it stimulates the release of vasoactive intestinal polypeptide (VIP) and calcitonin gene related peptide (CGRP), which in turn increase blood flow to the muscle. [As an aside here, we know that DMD is caused by the loss of dystrophin and that one of the main functions of dystrophin is to strengthen the muscle cell membrane during contraction and relaxation; however, when dystrophin is missing another molecule that manufactures the vasodilator nitric oxide (NO) is missing from the membrane—the loss of NO activity may impair the ability of the capillaries to maintain blood flow when they are squeezed during muscle contraction and contribute to the muscle damage seen in DMD]. When I spoke with Dr. Rhodes several months ago he mentioned that he had documented these changes in neuropeptide levels working with collaborators outside of Texas but that he didn’t have access to that data now.
Dr. Rhodes told me that every child he saw with muscular dystrophy had a significantly lower skin temperature in the fingers than would be expected, and that every child failed a “perception threshold” test that measures the amount of physical stimulus required for a person to be able to perceive that stimulus. Dr. Rhodes doesn’t know if these abnormal values return to normal with the use of the machine because he typically doesn’t see people for follow-up, but rather stays in touch afterwards by email. He also mentioned that a physician somewhere had tested circulating levels of the inflammatory marker TNF-alpha before and after two boys used the machine and found that the TNF-alpha levels declined significantly; he did admit however, that he doesn’t know how much TNF-alpha levels normally fluctuate. The evidence that Dr. Rhodes does have is detailed testimonials from families who have purchased the system. He is currently trying to collect survey responses from every family with muscular dystrophy who is using the machine.
I spoke with Dr. Rhodes about how we could go about evaluating the effectiveness of the machine in a more systematic manner. To even do a pilot clinical study would likely cost between $60,000-$100,000. A definitive clinical study would probably cost around $350,000. Typically when we spend money on a clinical study we have some objective evidence in hand that justifies the expenditure
In the case of Dr. Rhode’s VECTTOR machine we have only subjective testimonials, which shouldn’t be discounted but should be combined with some objective data. For example, Dr. Rhodes doesn’t actually know if his machine normalizes the perception threshold test that he says is abnormal in boys with DMD. He doesn’t know if VIP and CGRP are increased after using the machine and if so, by how much and for how long. He has heard that TNF-alpha levels are decreased after treatment, but he doesn’t know how much this molecule normally fluctuates. At the very least, before a pilot study should be considered, we should be able to find out if the machine is even affecting these parameters.
I discussed with Dr. Rhodes the possibility of identifying some volunteer physicians and families to test the device more objectively by measuring the concrete physiological changes the machine is supposed to cause. This would be a first step toward determining if a pilot study is warranted. Of course if the machine doesn’t trigger these changes it doesn’t mean that it might not be working through some unknown mechanism, but it does cast more doubt on the whole enterprise. If it does cause the physiological changes that Dr. Rhodes thinks it does, it doesn’t mean that the machine preserves muscle strength as well, but it provides more support for doing the clinical testing to measure muscle strength systematically.
I will be in London next week for the Action Duchenne meeting and Dr. Rhodes is trying to arrange for me to meet with some of the UK families who are using the machine and reporting good results. I will also be speaking with some investigators about how we might set up the collection of the preliminary measurements of physiological changes for the least expense and greatest gain.
This situation is one of the most complicated we face as a community—we have a very well-meaning man who has a proposed therapy for DMD that he really believes works, and yet he admits that he is not a scientist and doesn’t know how to go about testing it convincingly. In the meantime he is selling his machines to ever larger numbers of families, still with no concrete data that it’s effective. Typically when someone makes a claim about a product the responsibility lies with the person making the claim to demonstrate that it’s true.
In the best scenario we will be able to show the machine causes changes in muscle physiology that lead to stabilization of strength as Dr. Rhodes proposes. At worst, we will have put time and money into a project that never had a lot of supporting evidence behind it in the first place and moved resources away from projects that had greater odds of working