Smartphone-controlled TENS

Inspired by Joan Gan et al 2021 and Sha et al 2022.[1,2]

Joan Gan et al Figure 1.[1]

TENS – transcutaneous electrical nerve stimulation
EA – electroacupuncture
SCEA – smartphone-controlled EA (note this was not a form of EA)

key to acronyms

I found this paper from last year thanks to a letter written in response, which was published more recently.[2]

The letter is not so interesting, but it included the title of the original paper, and that piqued my curiosity with the phrase ‘smartphone-controlled patch EA’. So, I got the original paper, which is a small sham controlled trial of TENS applied at ST36 bilaterally for analgesia during colonoscopy.

To be clear, there is no EA in this trial…

To be clear, there is no EA in this trial, but TENS applied at an acupuncture point. The recent letter was correcting the point location described in the trial paper, which of course is quite irrelevant from the perspective of stimulation induced analgesia, since we are talking about stimulation to skin at a distance from the potential pain source both in terms of position and segmental innervation. Now, if they used real EA, that is electrical stimulation through needles placed into deep somatic structures, there may be bigger differences based on needle placement, although these difference are unlikely to be related to acupuncture points or finding them accurately, as I have highlighted in a recent blog: Missing to point in Guangzhou 2022.

This is a small trial of TENS, which normally I would not highlight, but I am doing so because the TENS was controlled and powered from a mobile phone via an audio jack. The control system for the TENS was an application on the device, which allowed adjustment of pulse width (50 to 300μs), frequency (0.5 to 33Hz), and intensity (25 to 100V). I was interested to see that you can get 100V output from the audio jack of a mobile phone, and I cannot help wondering how long the battery might last at maximum pulse width, frequency, and intensity – hopefully long enough to cover a colonoscopy.

I searched online for the kit needed to convert a mobile phone to a TENS machine, and found it here: O-Mass Smart TENS. I cannot find any information about how quickly it would drain the battery, but I guess it is not an issue since there is no mention of this in the paper.

The results showed a non-significant trend in favour of SCEA (real TENS) compared with the placebo version but there was little difference in the use of rescue medication between the groups. It was well received by the patients and the vast majority said they would be happy to use it again in both real and placebo groups.

If this sort of trial was to be repeated, since it is testing TENS and not EA, I would suggest placing the electrodes in a segmentally relevant area over the abdomen or back. Ideally in an area where discomfort from the procedure might be felt – low abdomen or sacrum.

References

1          Joan Gan CY, Chan KK, Tan JH, et al. Smartphone-controlled patch electro-acupuncture versus conventional pain relief during colonoscopy: a randomized controlled trial. ANZ J Surg 2021;91:E375–81. doi:10.1111/ans.16870

2          Sha T, Gao L, Xue L. Re: Smartphone-controlled patch electro-acupuncture versus conventional pain relief during colonoscopy: a randomized controlled trial. ANZ J Surg 2022;92:932. doi:10.1111/ans.17403


Declaration of interests MC