What makes you believe that the Monarch eTNS delivers under 3 mA? TENS machines used by physiotherapists have a range of 0 – 80 mA, though some machines may provide outputs up to 100mA. The only technical data I can find online regarding the Monarch eTNS is a Google summary that says “Stimulator current settings from 2 to 4 mA (range 0–10 mA) were …” The linked article you provided confirms that these currents do reach the brain. While these machines do not deliver a charge large enough to cause sufficient brain damage to induce a seizure, what damage they do cause is unknown. It will likely remain “unknown” until a number of lawsuits force the manufactures to admit what damage is done.