Dear Teri -

This is very exciting! And I am thrilled by your results.

I imagine the reticence of your doctors and physical therapist may have a lot to do with any potential risk in using a medical device for an off-label fashion, on the brain itself.

Quickly looking under PubMed, I was struck by the fact that a search of “Transcranial direct current stimulation CRPS” turned up no hits whatsoever, while a search of ” Transcranial direct current stimulation pain” was considerably more productive, with a total of 62 articles. And as to the reticence of the medical community to go off-label with tDCS, that may be “explained” – as these things go – by Arul-Anandam AP, Colleen Loo C, Perminder Sachdev P, Transcranial direct current stimulation - what is the evidence for its efficacy and safety? F1000 Med Rep. 2009; 1: 58, online text @ http://www.ncbi.nlm.nih.gov/pmc/arti...000000058.pdf:

Implications for clinical practice
The experimental findings described suggest that tDCS may emerge as a non-invasive therapeutic modality in the future, particularly for MDD, though there is a need for further replication in clinical trials, and clarification of the subgroup of patients most likely to benefit, before it can be recommended for clinical use. With a stronger evidence base, tDCS may present an attractive addition or alternative to available treatments for depression, particularly given its comparatively mild side-effect profile. For example, it may have a role in the treatment of patients unable to tolerate the side effects of antidepressant medications, and possibly in medication-refractory depression, if subsequent trials show efficacy in this subgroup. Moreover, tDCS has several advantages over other non-invasive forms of brain stimulation, such as transcranial magnetic stimulation: it is less expensive, less cumbersome and, therefore, more mobile, and may have longer lasting effects [31]. tDCS could thus be relatively easily implemented in a clinical setting. The evidence base is currently small, however, and more studies are needed before it can be recommended for general clinical application. In particular, a large multi-centric clinical trial is warranted to establish its efficacy and clinical utility. It is also too early to say whether optimal stimulation parameters have been discovered, and further work is necessary to establish this. [Emphasis added.]

Note
31. Fregni F, Freedman S, Pascual-Leone A: Recent advances in the treatment of chronic pain with non-invasive brain stimulation techniques. Lancet Neurol 2007, 6:188-91.

But at least the abstract to the paper by Fregni, Freedman and Pascual-Leone, who are among the top neuroscientists in the world, ends on what for many pain patients is the same frustrating note:

Abstract
BACKGROUND: Brain stimulation is a technique that can guide brain plasticity and thus be suitable to treat chronic pain-a disorder that is associated with substantial reorganisation of CNS activity. In fact, the idea of using invasive and non-invasive brain stimulation for pain relief is not new. Studies from the 1950s investigated the use of this therapeutic method for the treatment of chronic pain. However, recent advancements in the techniques of non-invasive brain stimulation have enhanced their modulatory effects and thus become a new, attractive alternative for chronic pain treatment. RECENT DEVELOPMENTS: Recent studies with non-invasive brain stimulation--eg, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS)--using new parameters of stimulation have shown encouraging results. These studies explored alternative sites of stimulation, such as the secondary somatosensory cortex (rather than primary motor cortex) for the treatment of chronic visceral pain and new parameters of stimulation, such as repeated sessions of tDCS with 2 mA for the treatment of chronic central pain. WHERE NEXT?: The investigation of non-invasive brain stimulation for therapeutic effects is in its at initial stages; but the preliminary data make us optimistic. Several questions still need to be addressed before any firm conclusion about this therapy is made. Other parameters of stimulation need to be further explored such as theta-burst stimulation and the combination of tDCS and rTMS. The duration of the therapeutic effects is another important issue to be considered, especially because the current devices for brain stimulation do not allow patients to receive this therapy in their homes; therefore, maintenance therapy regimens, as well as the development of portable stimulators, need to be investigated. Further trials must determine the optimum parameters of stimulation. After that, confirmatory, larger studies are mandatory. [Emphasis added.]

PMID: 17239806 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/pubmed/17239806

Accord, Rosen AC, Ramkumar M, Nguyen T, Hoeft F, Noninvasive transcranial brain stimulation and pain, Curr Pain Headache Rep. 2009 Feb;13(1):12-7, online text at http://www.ncbi.nlm.nih.gov/pmc/arti...ihms110681.pdf; O'Connell NE, Wand BM, Marston L, Spencer S, Desouza LH, Non-invasive brain stimulation techniques for chronic pain. A report of a Cochrane systematic review and meta-analysis, Eur J Phys Rehabil Med. 2011 Jun;47(2):309-26 at 324, (noting need in future studies for participant blinding when tDCS doses exceed 1 mA) online text @ http://www.minervamedica.it/en/freed...3Y2011N02A0309

Essentially, this may be yet another case of coming down to having the money to do the requisite studies. And unless a pharmaceutical company or an equipment manufacturer is willing to shell out millions of dollars for a “large multi-centric clinical . . . to establish . . . efficacy and clinical utility,” which may not be likely with your estimate of lifetime per patient revenues of only $1,500 – compared for instance to what a manufacturer clears for the sale of an SCS unit – we can’t except the private sector to foot the bill. Nor, in this age of incessant fiscal restraints, are we likely to see much assistance from the NIH, where chronic pain has never been one of its priorities.

That said, I came across one more (very recent) free article that makes for an encouraging read. Check out out:

Ross LA, McCoy D, Coslett HB, Olson IR, Wolk DA, Improved proper name recall in aging after electrical stimulation of the anterior temporal lobes, Front Aging Neurosci. 2011;3:16, Epub 2011 Oct 12, online text @ http://www.ncbi.nlm.nih.gov/pmc/arti...i-03-00016.pdf

Abstract
Evidence from neuroimaging and neuropsychology suggests that portions of the anterior temporal lobes (ATLs) play a critical role in proper name retrieval. We previously found that anodal transcranial direct current stimulation (tDCS) to the ATLs improved retrieval of proper names in young adults (Ross et al., 2010). Here we extend that finding to older adults who tend to experience greater proper-naming deficits than young adults. The task was to look at pictures of famous faces or landmarks and verbally recall the associated proper name. Our results show a numerical improvement in face naming after left or right ATL stimulation, but a statistically significant effect only after left-lateralized stimulation. The magnitude of the enhancing effect was similar in older and younger adults but the lateralization of the effect differed depending on age. The implications of these findings for the use of tDCS as tool for rehabilitation of age-related loss of name recall are discussed. [Emphasis added.]

PMID: 22016735 [PubMed] PMCID: PMC3191456

http://www.ncbi.nlm.nih.gov/pubmed/22016735

You bring us all hope.

Mike