Research

Various forms of electrical stimulation have been tried in medical contexts - more or less ever since electricity was first discovered. I think it is fair to say that in most circumstances the effects of electrical stimulation on the body are just the obvious - a big enough current can produce thermal damage, lower currents can trigger action potentials in the various cells which use ion flows across their cell membranes as part of their function - brain, nerve, muscle (including heart).  There is a fair amount of interest at present in low voltage DC stimulation of the brain which has been claimed to have effects on things like depression but the evidence for these effects is not fully concrete yet - the topic occupied a disproportionate amount of a European meeting I went to a few years ago but does not seem to have advanced greatly since then. Beyond that we get into lab studies - the sort of thing I suspect you have found - which have not yet been extended into clear clinical evidence of benefit in real patients, and 'fringe' medicine - things like electro-acupuncture which seems never to have been clearly shown to do any more than 'ordinary' acupuncture. There is also the curious issue of tasers - these interest me because I spend all day electrically stimulating the nervous system and I cannot produce the effects claimed for these devices, nor can I find any published scientific data explainining their claimed neuromuscular effects.

In the context of CTS in particular there are, predictably, a few reported experiments out there such as this one

Koca, I., et al. (2014). "Assessment of the effectiveness of interferential current therapy and TENS in the management of carpal tunnel syndrome: a randomized controlled study." Rheumatology International.
 We assessed the effectiveness of interferential current (IFC) and transcutaneous electrical nerve stimulation (TENS) therapies in the management of carpal tunnel syndrome (CTS) compared with splint therapy, a standard treatment modality for CTS. This was a prospective, single-blinded, single-center, randomized, three-group parallel intervention study of 3 weeks duration. Efficacy was examined in the third week after the end of treatments. Subjects were assigned randomly to one of three groups: group I patients received splint therapy, group II patients received TENS applied on the palmar surface of the hand and the carpal tunnel, and group III patients underwent IFC therapy applied on the palmar surface of the hand and the volar surface of the forearm. TENS and ICF treatments were applied five times weekly for a total of 15 sessions. Group 1 patients were stabilized with volar wrist splints for 3 weeks. The efficacy of the therapies was assessed before initiation of therapy and at 3 weeks after completion of therapy using a visual analog scale (VAS), a symptom severity scale, the functional capacity scale of the BCTQ, and measurement of median nerve motor distal latency (mMDL) and median sensory nerve conduction velocity (mSNCV). Groups were compared pairwise using the Mann-Whitney U test to identify the source of differences between groups. The Wilcoxon test was used to analyze changes in variables over time within a group. In the VAS, BCTQ, MDL, and mSNCV, no significant difference was observed between the groups (p > 0.05). In the VAS, BCTQ, and mSNCV, statistically significant improvements were detected in all groups (p < 0.05). There was no statistically significant difference between TENS and splint therapy with respect to improvement in clinical scores, whereas IFC therapy provided a significantly greater improvement in VAS, mMDL, and mSNCV values than splint therapy (VAS: 4.80 +/- 1.18 and 6.37 +/- 1.18; p = 0.001, mMDL: 3.89 +/- 0.88 and 4.06 +/- 0.61; p = 0.001, mSNCV: 41.80 +/- 1.76 and 40.75 +/- 1.48; p = 0.010). IFC therapy provided a significantly greater improvement in VAS, symptom severity, functional capacity, and mMDL and mSNCV values than TENS therapy (VAS: 4.80 +/- 1.18 and 6.68 +/- 1.42; p < 0.001, symptom severity: 2.70 +/- 1.03 and 3.37 +/- 1.21; p = 0.015, functional capacity: 1.90 +/- 1.21 and 2.50 +/- 0.78; p = 0.039, mMDL: 3.89 +/- 0.88 and 4.06 +/- 0.88; p = 0.003, and mSNCV: 41.80 +/- 1.76 and 41.38 +/- 1.78; p = 0.021). IFC may be considered a new and safe therapeutic option for the treatment of CTS.

Single small studies like this (63 patients in three groups of about 20 each) should be treated with great caution as they are subject to all kinds of risks of bias, of which the most important one which is unlikely to be appreciated by the lay reader is 'publication bias'. It may well be that 5 different groups have tried this out and four of them found no effect but the only one that is likely to make it into print is the one which, by chance, came out with a positive finding. One also needs to be wary of only partially blinded interventions. This study is described as 'single blind' but the blinding is poorly described in the text. It is likely that the patients knew which treatment they were receiving, certainly the TENS group would know, raising the possibility of placebo and nocebo effects. Finally I am also wary of studies which measure thirty different things before and after treatment and trumpet a positive effect if one or two of them show a 'statistically significant' change. This is becoming all too common in the CTS literature as the range of things which we can measure grows. Any statement like the last one in that abstract about a new and unusual treatment is, in my opinion a warning sign about the paper in general. Careful investigators do not make such certain statements on the basis of flimsy evidence. It's also worth noting that the follow-up period in this study was only 3 weeks.

If you want to experiment with the effects of electrical stimulation on CTS then there is certainly room for some new work. You will need a population of people with very clearly demonstrated CTS so that there is no uncertainty about what condition we are dealing with and it will be easier to design a good experiment if the stimulation being used is below sensory threshold so that the subject cannot tell whether the stimulator is switched on or not - you can then carry out a true placebo controlled trial.

In your own case we have both the possibility of diabetic neuropathy and CTS to consider and one would want to know what your neurophysiological results looked like before commenting on what it is worth trying.

If you don't mind, in a day or two, I will move this to CTS forum rather than the website forum as it is realy about CTS, not about the technical aspects of the website. JB