General Mechanisms

Somatosensory therapies

I noticed that I wrote a lot about acupuncture in my last post. This does not give justice to the fact that my research interests are somewhat broader. The name of the research group I am heading at Hannover Medical School (in Germany) translates “Somatosensory and Autonomic Therapy Research”. As the term somatosensory therapies is rather non-standard, this deserves some explanation.

When you look at the field of complementary medicine from a naïve scientific perspective you will soon identify a large group of therapies whose interventions are very similar to each other. (Needless to say that this only works if you ignore all explanations given by proponents of the single therapy systems, otherwise they are of course very different…) Those therapies all apply some form of bodily stimulation, i.e. stimulation of the skin, muscles, connective tissue or bones. The means of stimulation are very diverse and range from mechanical (e.g. acupuncture, manual stimulation, or cupping), through thermal (e.g. moxibustion) to electrical (e.g. electroacupuncture) or even chemical (e.g. injection of irritants). You can further differentiate between invasive and non-invasive interventions.

I call these therapies somatosensory therapies.* The reason is that all of them stimulate the somatosensory system, i.e. the part of the nervous system processing sensory information coming from the body and going to the brain. This is easily proven by the fact that you conciously perceive the stimulation. For instance, an acupuncture needle that is stuck in your arm will hardly go unnoticed. Interestingly, similar therapies are widely used in conventional medicine. Think about massage, thermotherapy, TENS, or application of topical irritants, like capsaicin (e.g. in plasters).

Of course stimulation of nerves may theoretically be a pure byproduct of those therapies and may be completely irrelevant for the treatment effect. But as the last decades of research have shown, there are numerous mechanisms, how stimulation of somatic nerves can have quite dramatic effects on the body. The effects range from analgesia through autonomic regulation to immunomodulation as recently shown for electroacupuncture and electrical nerve stimulation in a Nature Medicine paper.

Thus, it seems like a good idea to start from the premise that all these therapies develop at least part of their effect from stimulation of somatosensory nerves.

The future will show if this is a fruitful hypothesis or not.

*Part of the credits for this goes to my friend Vitaly Napadow, who always speaks of acupuncture as a somatosensory-guided therapy.