I'll throw out one more suggestion. tDCS does not penetrate deep in the brain. There is a remarkably simple, non-invasive, cost-free method to stimulate deeper brain structures: it's called (caloric) vestibular stimulation.

You simply lie down in bed with a towell beneath your head, and then put ice cold water (using an eyedropper) into the ear contralateral to (on the opposite side of) your worst pain for 30-60 seconds. The cold stimulation will provoke nystigmus (eyes rapidely darting back and forth) and vertigo; you will probably want to keep your eyes closed, and you definitely do not want to be on your feet during this procedure! Functional imaging shows that the procedure activates a number of deeper brain structures, including the insula which are involved with pain processing.

You can search for the handful of papers exploring this form of stimulation at PubMed. Ramachandran's group claims remarkable and lasting pain relief from a single treatment in several CRPS patients. Most of the papers consist of case reports (an exception being central post-stroke pain). The lack of a definitive study for CRPS invites some doubt, but the procedure is definitely worth a try. Unfortunately, it appears to work much better for upper-body pain, so it hasn't benefitted my wife's condition.

My suggestion is to consider this treatment in combination with tDCS. I see no reason why you can't do the ice-water treatment once a day over an extended period of time.

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Iguanabill :

thanks for your posts. Pretty darn informative and educational.
I'd love to see you, ballerina & whoever else feels confident enough, discuss your best guesses as to what's going on in tDCS…

I'm actually reasonably well-educated on the theories of electromagnetic wave propagation, etc. but what's going on with the brain and tDCS still baffles me. I'm a practical person – so I don't need to know what's going on -- but I'm a curious person, so I'd like to hear some ideas from people who don't have to consider all the ins and outs of a research publication to express their ideas.

On another note -- I'm curious if anybody has any simple and inexpensive techniques for vagal nerve stimulation? One of my other symptoms is that my autonomic system is messed up – ramped towards the sympathetic side…

Thanks!

In a nutshell, tDCS modulates spontaneous neuron activity by increasing or decreasing the thresholds that determine whether the neurons send a signal. The relatively local effects of tDCS can spread throughout the brain by networks of interconnecting neuron circuits.

There are some forms of vagal stimulation you could try: gagging, holding your breath while bearing down (Valsalva maneuver), immersing your face in ice-cold water (stimulating the diving reflex), and coughing. I'm not sure whether these would have a lasting effect. Sympathetic blocks (injecting lidocaine or bupivicaine) can help reduce sympathetic activity; though they are most effective regionally (placed near the sympathetic ganglion chain), some patients respond to i.v. (total body) infusions. My wife's sympathetic issues always improved with ECT. There are also more permanent but invasive approaches (implanting a stimulator).

Please see below for an overview of neuromodulation procedures.
http://www.ncbi.nlm.nih.gov/pmc/arti...3/?tool=pubmed

In the long term picture, tDCS is really in its infancy. Having posed this question to the top three tDCS folks in the country the bottom line is no one really understands exactly how and why tDCS or why it works for some and not for others.

Did you happen to ask him what experience he has with treating CRPS patients who have failed spinal cord stimulators?

How do I say this gently? We used the ice water injection into the ear to test for brain activity ' as in brain death, about 30 years ago in ER, checking the pupils reactions, before we stopped CPR, we stopped if there was no reaction. I am not sure how this would relate to pain suppression...

Here is a smattering of publications (there are others) that answer your questions:

Miller SM, Ngo TT. 2007. Studies of caloric vestibular stimulation: implications for the cognitive neurosciences, the clinical neurosciences and neurophilosophy. Acta Neuropsychiatrica 2007: 19: 183–203

full review article available here: http://www.pcng.org.au/IMG/pdf/CVSreview2007.pdf

McGeoch PD, Williams LE, Lee RR, Ramachandran VS. 2007. Behavioural evidence for vestibular stimulation as a treatment for central post-stroke pain. J Neurol Neurosurg Psychiatry 2008;79:1298–1301.

abstract here: http://jnnp.bmj.com/content/79/11/1298.abstract

Williams LE, Ramachandran VS. 2006. Novel experimental approaches to reflex sympathetic dystrophy/complex regional pain syndrome type 1 (RSD/CRPS -1) and obsessive-compulsive disorder (OCD). ABSTRACT. Neuroscience Meeting Planner. Atlanta, GA: Society for Neuroscience, 2006.

excerpt from the abstract (only the abstract was published): "...we irrigated the ear of a patient with RSD with cold water to produce vestibular caloric stimulation accompanied by nystagmus. The procedure produced a striking reduction of pain from a 7 to 4 on a visual analog scale. No such reduction occurred in two placebo controls, lukewarm water in the ear or ice cube placed on the forehead. This patient reported no reduction in pain from previous treatments with a spinal cord stimulator, a pain pump, ganglion blocks, or a transcutaneous electrical nerve stimulation (TENS) unit. We postulate the caloric stimulation activates the vestibular cortex and other areas which then “mask” the sympathetic pain in the adjacent insular cortex."

Ramachandran VS, McGeoch PD, Williams L, Arcilla G. 2007. Rapid Relief of Thalamic Pain Syndrome Induced by Vestibular Caloric Stimulation. Neurocase (2007) 13, 185–188.

full article available here: http://cbc.ucsd.edu/pdf/rapid%20relief%20caloric.pdf

Yesterday evening I dug up some research on this form of brain stimulation and decided to try it since it is very low risk. (vertigo, nausea and headache-no big deal)

Unfortunately this did not work for me. It ignited a nasty pain flare in my jaw, an area of neuropathic pain that had been down to a dull roar. My balance worsened, as I suspected it might, to the point that I could not even sit up for dinner. Although I did not have nausea I developed a searing headache which I still have this morning. I am planting myself in a chair this morning because my balance is so impaired that I fear falling.

This was certainly worth a shot for me to try based on a quick lit review, and I hope it works for others. I would exercise caution, however, if you have balance issues or are prone to headaches.

Bummer! My wife tolerates it okay, but it hasn't helped her. I tolerate it okay myself (yes, I've given it to myself, though I have no pain issue). No one treatment is good for everyone, that's for sure.

We tried the motor cortex/secondary somatosensory cortext tDCS stimulation the night before last, and my wife had a bad headache (something she virtually never suffers) and severe pain yesterday. While there's no doubt what got your headache going, we're just not sure what provoked my wife's headache. We're doing each other a lot of good! (lol)

My wife is now at 20 treatments over 11 days, and hasn't seemed to get anywhere, but we only targeted the secondary somatosensory cortex the one time. We took a holiday from tDCS yesterday. I think we'll try it again tonight or in another few days.

Have a blessed weekend, ballerina. You deserve it.

I got headaches the first time I tried tDCS at Beth Israel but they vanished by the third day of treatment. The resident giving the treatment suggested that I take an extra strength excederine prior to my treatment for day 3 which I did. I had no more headaches after that.

Headache is reported in the literature as a side effect that subsides, but many studies also report headache for the placebo group-wierd huh?

I am praying for your wife to get relief from the next round of treatments. If the next round does not work there are more portocols to try. As soon as I am finished my current round of treatment I will decide on what to try when the treatment wears off, which I hope will be a good while with booster treatments. I am getting very greedy-I want remission and I think over time it is a real possibility!

Have a great weekend!