Neuropathy And Electro Stimulation Part 3

Today's post from absolutept.com (see link below) is the third of 4 looking at the qualities and effectiveness of EMS or Tens units in helping reduce neuropathic symptoms. Not all experts are fans of TENS systems, or believe that electro-stimulation is beneficial to neuropathy patients but as with so many of these things in the neuropathy world; they work for many people and bring relief, so deserve to be taken seriously. The problem may be that to get treatment in this area, many people have to go to private clinics and pay outside their normal insurance and that immediately raises the spectre of rampant commercialism and leads people to suspect they're going to be ripped off. This blog doesn't normally advertise but when someone provides useful and fact based information, which is of benefit to everyone considering their treatment options, then there is no objection to highlighting a medical facility. That's the case here. Chad Reilly (sports physical therapist) provides such a comprehensive analysis of EMS/TENS that patients may wish to take it further, either with him or their local TENS provider. Definitely worth reading if you want to know more about how it all works. All four sections appear within these four days.

 Electric Stimulation and Neuropathy (Part 3)
 Chad's Physical Therapy Blog - Chad Reilly

Effective treatment of symptomatic diabetic polyneuropathy by high-frequency external muscle stimulation. Diabetologia. 2005 May;48(5):824-8. Reichstein L, Labrenz S, Ziegler D, Martin S.


Abstract
AIMS/HYPOTHESIS:
Diabetic distal symmetrical sensory polyneuropathy (DSP) affects 20-30% of diabetic patients. Transcutaneous electrical nerve stimulation (TENS) and electrical spinal cord stimulation have been proposed as physical therapies. We performed a controlled, randomised pilot trial to compare the effects of high-frequency external muscle stimulation (HF) with those of TENS in patients with symptomatic DSP.


METHODS:
Patients with type 2 diabetes and DSP (n=41) were randomised to receive treatment with TENS or HF using strata for non-painful (n=20) and painful sensory symptoms (n=21). Both lower extremities were treated for 30 min daily for three consecutive days. The patients’ degree of symptoms and pain were graded daily on a scale of one to ten, before, during and 2 days after treatment termination. Responders were defined by the alleviation of one or more symptoms by at least three points.

RESULTS:
The two treatment groups were similar in terms of baseline characteristics, such as age, duration of diabetes, neurological symptoms scores and neurological disability scores. The responder rate was significantly higher (p less than 0.05) in the HF group (80%, 16 out of 20) than in the TENS group (33%, seven out of 21). Subgroup analysis revealed that HF was more effective than TENS in relieving the symptoms of non-painful neuropathy (HF: 100%, seven out of seven; TENS: 44%, four out of nine; p less than 0.05) and painful neuropathy (HF: 69%, nine out of 13; TENS: 25%, three out of 12; p less than 0.05). The responders did not differ in terms of the reduction in mean symptom intensity during the trial.

CONCLUSIONS/INTERPRETATION:
This pilot study shows, for the first time, that HF can ameliorate the discomfort and pain associated with DSP, and suggests that HF is more effective than TENS. External muscle stimulation offers a new therapeutic option for DSP.

My comments:

I would have really liked this study had it shown great results with the high frequency (HF) electric stimulation, and compared it to TENS and found the HF worked considerably better. The next study I am going to cite uses the exact same HF machine and calls it EMS (electric muscle stimulation) rather than HF, and that fits with my observations and other research that EMS works better than TENS to control pain.

What I don’t like about this study, however, is that from the description of the parameters I can’t figure out what they used. Plus, other things besides the current are different, including electrode size and placement.

For the TENS group I get:
Waveform: biphasic exponentially decaying
Duty Cycle: continuous (I think)
Pulse Duration: 400 uS
Intensity: 20-30 mA
Rate: 180 Hz
Treatment Length: 30 min
Training Frequency: daily
Training Length: 3 days
Electrodes: two sticky ~2” electrodes per leg, placed on proximal and distal fibula region

For the HS group:
Waveform: biphasic exponentially decaying
Duty Cycle: 3 sec ramp, 3 sec on (3 sec off I think, because that’s what the next study using the same machine reports)
Pulse Duration: does not say but with the high Hz I expect its pretty short
Intensity: adjusted to a pleasant level without pain or uncomfortable paresthesia
Rate: 4096 Hz – 32768
Treatment Length: 30 min
Training Frequency: daily
Training Length: 3 days
Electrodes: two carbon ~3.5” rubber carbon electrodes per leg, placed on the proximal and distal quadriceps.

So in this study the HS group did a lot better, but it is hard to tell if it is due to the difference in current, or the larger electrodes being used in the HS group, or the HS group putting the electrodes over a muscle rather than a bony region. I would expect the larger electrodes to work better because you can turn the machine up higher with greater patient comfort because of lesser current density (coulumbs delivered per square inch of skin). Also I don’t think it’s at all ideal to place the smaller electrodes over the bony region of the fibula, though I find it interesting that the larger electrodes on the quadriceps worked so well since presumably the diabetic neuropathy sufferers were complaining of the most pain and paresthesias in the feet. Another interesting thing is the good results of the HS group was noticed in just 3 days of treatment, which is in accordance with my observation using EMS. My patients report relief immediately after my 12 minute treatment, and those results continue to improve with future treatments. Also interesting from this study is they treated people with both painful and non painful neuropathy, noting it worked on non-painful neuropathy better. My patients tend to report similar improvements painful or not with my protocol, but that could be due to the different parameters where I’m using 4 electrodes per leg instead of two, placing all the electrodes on muscle (including the bottom of the foot), my electrodes are larger still, and I use as long a pulse width as my machines allow (300-450 uS) for as high an intensity as they can tolerate.

So the take home message for me is that all stimulation parameters are not equal, but in this study it is unclear which part of the different stimulation protocols led to the difference in effects. I suspect that greater intensity of stimulation, and on and off period, larger electrodes, placing the electrodes over muscle all contributed to better outcomes in the latter group.

http://absolutept.com/electric-stimulation-and-neuropathy-part-3/