I have recently become aware of TenS, but have yet to find any definitive evedance it is either a legitimate treatment or a fully-blown pseudo-science.

The closest was this BBC article:

Some of the claims made for TENS could lead you to think it's the miracle cure for pain. Back pain, arthritis, migraine, sports injuries, period pains and even non-painful conditions such as sleeplessness and stress are said to improve with its use.

But while TENS is widely recommended in the UK as a way of controlling labour pain, a review by the Pain Research Unit at Oxford University, published in 1997, found that evidence for it having an analgesic effect in such circumstances was weak. The unit could find no study of note showing any difference in pain intensity or pain relief scores between TENS and a placebo treatment during labour. There has not been any substantial study since, supporting its use.

Can anyone link or summarise some decent papers investigating TeNS.

Is this a niche treatment that salespeople are trying to push in the mainstream?