SkeptVet’s Acupuncture Adventure- Part 6: Neuromodulation of Cranial Nerves

The latest lectures in my acupuncture course have covered the use of acupuncture (and, incidentally, massage and laser therapy) for “neuromodulation” of the twelve cranial nerves. “Neuromodulation” is a somewhat vague term often used to suggest some clinically relevant and likely beneficial effect on the function of the nervous system. More casually, this is described with terms like “give it a boost” or “help that nerve be a happier nerve.” This is a theme in this course, in which the fact that needling, electrical stimulation, and possibly laser stimulation have measurable effects on nerves is assumed to imply clinically meaningful and beneficial effects in patients. As I’ve said before, this is a plausible hypothesis, but it has to be proven with appropriate clinical research, which often turns out not to be the case.

Many of the cranial nerves are not directly accessible, and often they have functions that are not likely to be associated with clinical problems we deal with in veterinary patients. However, some nerves, especially CN V, VII, VIII and X do have functions associated with fairly common and important clinical problems, so modulation of these functions could potentially have clinical value.

Much is made in these lectures of the anatomic relationships between elements of the nervous system, with the implication that these anatomic connections imply relevant functional connections we can manipulate with acupuncture. However, it is important to realize that one can’t reliably infer functional relationships solely form anatomic relationships. Exercise, for example, stimulates gastrointestinal motility despite the lack of a simple and obvious anatomic relationship to predict this. On the other hand, the spinal cord is pretty widely and directly connected to nearly everything in the body, yet the evidence is strong that chiropractic manipulation of the spine has virtually no significant effects on the body apart from the spine itself. The obvious anatomic relationship turns out not to have a corresponding functional relationship.

The real question, of course, is whether there is actual clinical value to acupuncture etc. in patients with problems that we might reasonable suspect could be influenced by modulation of cranial nerves. That seems to be far from clear based on the evidence presented in these lectures.

As an example, the role of acupuncture in controlling seizures is mentioned several times. Direct and indirect stimulation of CN V and CN X are suggested as likely ways to influence seizures due to anatomic and functional relationships between these nerves and the parasympathetic nervous system, which does play a role in controlling seizure activity. And there is evidence that direct stimulation of CN X via an implanted electrical nerve stimulator. However, this is clearly not the same thing as acupuncture. So what does the clinical evidence suggest?

As usual, there is poor evidence in veterinary patients. A couple of uncontrolled studies in dogs have been done. One suggested improvement in seizure frequency, but such improvement has also been seen in epileptic dogs receiving placebo treatment, so uncontrolled studies can’t be taken as reliable evidence of an effect. The evidence is still limited and at high risk of bias in humans, but there is more research, and reviews do not suggest a strong or repeatable clinical benefit.

Cheuk DK, Wong V. Acupuncture for epilepsy. Cochrane Database Syst Rev. 2014 May 7;5:

We included 17 RCTs with 1538 participants that had a wide age range and were suffering mainly from generalized epilepsy. The duration of treatment varied from 7.5 weeks to 1 year. All included trials had a high risk of bias with short follow-up. treatment in the included trials.

Available RCTs are small, heterogeneous and have high risk of bias. The current evidence does not support acupuncture for treating epilepsy.

Yang C, Hao Z, Zhang LL, Guo Q. Efficacy and safety of acupuncture in children: an overview of systematic reviews. Pediatr Res. 2015 Aug;78(2):112-9.

We aim to update the evidence for the efficacy and safety of acupuncture for children and evaluate the methodological qualities of these studies to improve future research in this area. We included 24 systematic reviews, comprising 142 randomized controlled trials (RCTs) with 12,787 participants. Only 25% (6/24) reviews were considered to be high quality (10.00?±?0.63). High-quality systematic reviews and Cochrane systematic reviews tend to yield neutral or negative results (P = 0.052, 0.009 respectively). The efficacy of acupuncture for five diseases (Cerebral Palsy (CP), nocturnal enuresis, tic disorders, amblyopia, and pain reduction) is promising. It was unclear for hypoxic ischemic encephalopathy, attention deficit hyperactivity disorder, mumps, autism spectrum disorder (ASD), asthma, nausea/vomiting, and myopia. Acupuncture is not effective for epilepsy. Only six reviews reported adverse events (AEs) and no fatal side effects were reported. The efficacy of acupuncture for some diseases is promising and there have been no fatal side effects reported. Further high-quality studies are justified, with five diseases in particular as research priorities.

Another example was the condition of xerostomia or “dry mouth.”  This can occur with radiation or surgical therapy around the mouth as well as for other reasons, It is hard to assess in veterinary patients and so not a regular target for therapy, but it is used as an example in these lectures of clinical benefits from neuromodulation through acupuncture, in this case of CN IX. However, the evidence in humans does not suggest that the theoretical benefits of acupuncture stimulation of CN IX translate into significant benefits for actual patients with xerostomia.

Jedel E. J Oral Rehabil 2005 Jun;32(6):392-6. Acupuncture in xerostomia–a systematic review.

The aim of this systematic review was to assess the efficacy of acupuncture in the management of xerostomia….Three articles met the criteria for inclusion and a criteria list was used to assess the quality of these studies. The studies were considered to be of high quality or low quality in accordance with the criteria list utilized. The results of the trials were considered positive, negative or indifferent based on statistically significant between group differences. The criteria list utilized indicate that one of the three studies was of high quality and it presents indifferent results. One of the two studies of low quality presents positive results and one presents indifferent results. An analysis of the results degree of evidence resulted in no evidence for the efficacy of acupuncture in the management of xerostomia. This systematic review shows that there is no evidence for the efficacy of acupuncture in the management of xerostomia. There is a need for future high quality randomized controlled trials.

Wu X, Chung VCh, Hui EP, et al. Effectiveness of acupuncture and related therapies for palliative care of cancer: overview of systematic reviews. Sci Rep. 2015 Nov 26;5:16776.

…There is evidence for the therapeutic effects of acupuncture for the management of cancer-related fatigue, chemotherapy-induced nausea and vomiting and leucopenia in patients with cancer. There is conflicting evidence regarding the treatment of cancer-related pain, hot flashes and hiccups, and improving patients’ quality of life. The available evidence is currently insufficient to support or refute the potential of acupuncture and related therapies in the management of xerostomia, dyspnea and lymphedema and in the improvement of psychological well-being. No serious adverse effects were reported in any study.

Hanchanale S, Adkinson L, Daniel S, et al. Systematic literature review: xerostomia in advanced cancer patients. Support Care Cancer. 2015 Mar;23(3):881-8.

Limited published data exists reporting the effectiveness of measures in the treatment of xerostomia in cancer patients. Based on primary research of low quality, firm conclusions cannot be drawn. However, pilocarpine, artificial saliva, chewing gum and acupuncture can be tried based on the available data. This highlights the explicit need to improve our evidence base. Properly constructed randomized controlled trials demonstrating effectiveness of pharmacological and non-pharmacological interventions for dry mouth are required.

Furness S, Bryan G, McMillan R, et al. Interventions for the management of dry mouth: non-pharmacological interventions. Cochrane Database Syst Rev. 2013 Sep 5;9:CD009603.

There were nine studies (total 366 participants randomised) included in this review of non-pharmacological interventions for dry mouth which were divided into three comparisons. Eight studies were assessed at high risk of bias in at least one domain and the remaining study was at unclear risk of bias….There is low quality evidence that acupuncture is no different from placebo acupuncture with regard to dry mouth symptoms, which is the most important outcome …There is insufficient evidence to determine the effects of electrostimulation devices on dry mouth symptoms. It is well known that dry mouth symptoms may be problematic even when saliva production is increased, yet only two of the trials that evaluated acupuncture reported dry mouth symptoms, a worrying reporting bias. There is some low quality evidence that acupuncture results in a small increase in saliva production in patients with dry mouth following radiotherapy….Reported adverse effects of acupuncture are mild and of short duration, and there were no reported adverse effects from electrostimulation.

Similar results are found when the other main examples of purported neuromodulation of cranial nerves through acupuncture are investigated. What this says to be is that despite plausible anatomic relationships that suggest acupuncture could be useful in altering the function of these nerves to the benefit of patients, it seems to be very difficult to prove in the real world. This might mean we need more and better research, as the reviews usually conclude. Or it might mean that there is no effect to find. Certainly, therapies with a strong and definitive benefit aren’t not usually difficult to validate in clinical research, so the difficulty in showing benefits for acupuncture is reason for some skepticism.

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8 Responses to SkeptVet’s Acupuncture Adventure- Part 6: Neuromodulation of Cranial Nerves

  1. v.t. says:

    I’m hoping that at some point nearing completion of your courses, you’re not swayed to employ acupuncture in practice just to recover your costs for the courses.

    Of course I can’t fathom you would do that, since you’re Skeptvet and have a conscience, superpowers and all that. But, seriously.

  2. skeptvet says:

    I certainly wouldn’t be tempted to use acupuncture in practice just to pay off the course (much of which is actually being covered as CE by my practice anyway). I’m mostly interested in whether or not there’s a small pony buried under the mountain of horse#$%& that has collected around the various practices and theories that use the term. If we throw out Qi and Yin/Yang and point/channel maps and all of that, might there be a few useful things? I suspect that some of what gets called acupuncture is really just subcutaneous electrical nerve stimulation, which does have some legitimacy. The question is how to tease out such things from all the dross, and how to make use of it without unintentionally validating all the BS. Tricky……

  3. Art Malernee dvm says:

    How much does the acupuncture course cost? If my wife found out I paid for a acupunture course I would hear about it every time she wanted to buy something a thought we could not afford.

  4. v.t. says:

    Thanks for that, skeptvet, I truly know better.

    That said, even if subcutaneous electrical nerve stimulation showed the least bit of promise, shouldn’t further investigation be considered from, say, veterinary neurologists (rather than acupuncturists who are not specialists) who may be better qualified to understand/show whether there is a benefit?

  5. skeptvet says:

    Yes, I’ve heard a similar line from my wife a few times over the years! 🙂

    This page has all the details on the course I’m taking.

  6. skeptvet says:

    Well, if reasonable evidence shows that electrical stimulation at the site of a particular nerve has some clinical benefit, I don’t see why a neurologist would need to be the one to apply the therapy. Obviously, specialization is much less common in vet med than human med, so if I can do cardiac ultrasound, soft-tissue surgery, and chemotherapy, I don’t see why I couldn’t perform subcutaneous electrical nerve stimulation.

    If the evidence is only suggestive but not clear, as it is for many veterinary therapies, then it comes down to what we do in practice while awaiting confirmation. Plenty of vet therapies are not well-supported by clinical trial evidence. There is always the need to balance the urgency of taking action against the degree of uncertainty about the effects. The problem with most alternative therapies isn’t that they don’t have strong, high-level evidence to support them, because this would not be different from most veterinary treatments. The problem is that they are often implausible or irrational and so theoretically shouldn’t be able to work to begin with, AND they lack good evidence showing they do work, AND their proponent make confident claims based on personal experience and don’t really even try to produce legitimate scientific evidence concerning their therapies or honestly inform clients of the uncertainty.

    As an example, post-operative ileus (lack of intestinal motility) in patients with GI foreign bodies can be a significant clinical problem. It causes significant discomfort and mortality, so there is some urgency to intervene to treat it if we can. We often treat this with metoclopramide, cisapride, and other drugs, but there is little evidence to support this practice. The real risks and benefits of these drugs aren’t clear, and their use is based largely on pre-clinical research and reasoning form basic physiology. Not great, but sufficient to try, with proper informed consent, since the problem is serious enough to balance the uncertainty.

    So, it turns out there is some limited but decent animal model evidence (e.g.) that electrical stimulation at certain “acupuncture points” objectively increases GI motility in dogs And there are some plausible (though I find them kind of unconvincing) anatomic connections in the nervous system that could possibly explain a relationship between such stimulation and GI function. No clinical trials in vet species, but suggestive evidence from lab animals and humans.

    Since the risk is no higher than for the drugs we already use (I’ve certainly seen metoclopramide toxicosis), the plausibility is about the same, and the evidence is poor for both but about equal, would it be wrong to try this therapy on a dog with ileus refractory to other treatments, provided proper informed consent was given? Would it be ok if I called it “subcutaneous electrical nerve stimulation” but not ok if I called it “acupuncture?” If it works, of course it doesn’t validate the whole mess of inconsistent ideas lumped under the heading of “acupuncture,” even if some will claim it does. But should we avoid it just because it might make some nonsense look more believable?

    I think these are difficult questions. I don’t want to lend more legitimacy to the mountains of BS associated with acupuncture (Qi, tongue and pulse diagnosis, traditionally assigned points, and all the other alt med baggage that usually accompanies the practice). On the other hand, I don’t want to ignore potentially useful treatments, even if there likely aren’t many, that are buried under that mountain just because I’m afraid to be tainted by association. And if I could protect some clients from referral to the TCM folks, which my colleagues offer all the time, by doing some things that sound like acupuncture but at least have some reasonable basis in science, would I be doing more good than harm? Honestly, I don’t know, which is why I’m trying to think carefully about these issues.

    Ultimately, if there are some practices that seem to have a plausible mechanism, good pre-clinical and perhaps clinical evidence to support some effects and minimal risk, and if I can honestly talk to clients about the evidence and not send them down the rabbit hole of TCM, I still think there might be some value in this even if it looks like I’m “drinking the Kool-Aid” to some. If I’m not afraid to follow the evidence when it shows certain practices to be BS, despite the steady stream of hate mail this earns me, I guess I shouldn’t be afraid to follow it even if it shows a few dubious practices to be more reasonable than I would have expected, despite the additional hate mail from fellow skeptics this might get me. 🙂

  7. Art Malernee dvm says:

    This page has all the details on the course I’m taking.>>>
    It’s funny how who you are needling makes a difference to us. Stick a needle in an adult or a dog and no big deal. The vets who work at the vet school in Florida and Colorado are ok working at a hospital where other doctors needle their patients. My wife is a nicu nurse who care for babies that weigh less than one pound. Can you imagine how you or a Nicu physician would react if you visited your premie in nicu and the baby next to yours had 4 acupuncture needles sticking out from its head and neck?

  8. zyrcona says:

    “If I’m not afraid to follow the evidence when it shows certain practices to be BS, despite the steady stream of hate mail this earns me, I guess I shouldn’t be afraid to follow it even if it shows a few dubious practices to be more reasonable than I would have expected, despite the additional hate mail from fellow skeptics this might get me.”

    Well, this is one of the things that sets real scientists apart from charlatans and ‘believers’. A rationally held understanding must always be subject to change upon the emergence of new evidence. The holder of irrational beliefs reacts with objection and denial when confronted with any evidence that threatens their position, claiming it is a conspiracy or suchlike. If fellow sceptics send hate mail to you for investigating something and seeking evidence, they’re probably more in the ‘belief’ camp than the ‘understanding’ one.

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