Often patients enter for treatment for pain and find immediate relief once an interventional clinical machine is applied to them. Most people do not know the name of the type of electrotherapy but will recognize lying on a treatment table, 4 "electrode pads" put on them and the machine turned on and power increased until the patient says to the clinician, "that feels good" . Usually this is an interferential machine.
Interferential therapy is used for:
- Immediate pain relief
- Carryover pain relief
Carryover pain relief is not related to a numb sensation per se, or at least to my knowledge it is not. You can create what is called "paresthesia" with high frequency estim. High frequency is generally referred to in electrotherapy as more than 1,000 pulses per second (PPS). All PPS means is how many times per second does the machine go off and on. Interferential is a form of high frequency therapy.
Much of how our body responds to electrical stimulator is not known. When you put positive and negative charges in the body you create a cascade effect of numerous electrical changes which are defined as literally changing the chemical structure of cells, nerves, inter and intra cellular spaces. With arrogant one can cause more changes, very quickly in the body.
With pain the changes tend to be beneficial and one has immediate pain relief results. That relief is very much predicated upon the chemical changes one did during the period of stimulation. That relief remains as long as there is similar chemistry in the area or the change has affected how the brain reacted to the changes. The brain can change chemistry within our body and does consistently. Interferential on an "as needed" basis appears to be teaching the brain to either send different chemical responses or not allow certain previous chemical reactions to occur. It may prohibit chemical changes such as an unwarranted "pain signal" from reoccurring without some new pain stimulus. It's not always what is done, but often what is not done.
Unlike the traditional tens type machine, the therapy from an interventional machine allows for short treatment periods and long periods of pain relief. A tens machine requires constant use, or the pain returns almost immediately. Interferential when used in a routine home setting can actually start to prevent pain, not treat pain. It is the prevention that has originally been used in professional settings to treat and then teach to prevent re-occurrence.