Somatosensory Evoked Potentials in the Investigation of Auricular Acupuncture Points

A preliminary study correlating the wrist and gall bladder body areas with their auricular acupuncture points, through recording the somatosensory evoked potentials (SEP) at the corresponding brain localisation, showed that stimulation of the “Wrist” auricular point activates the primary cortical somatosensory area of the upper extremity on the contralateral hemisphere in a similar way to direct median nerve stimulation. A “placebo” point 5 to 8mm from the “Wrist” auricular point was used as a control: no activation in the brain area was observed. In patients with post-stroke hemiplegia, SEP traces obtained both by direct median nerve stimulation at the wrist, and by stimulation of the “wrist” auricular point, were altered in a similar manner and only on the damaged side. Similarly, “gall bladder” auricular point stimulation activates the corresponding cortical somatosensory area in the same way as direct stimulation of the T7 intercostal nerve. Again, a “placebo” point, 5 to 8mm away from the “Gall bladder” auricular point, was used as a control, and activation in the brain area was not observed. Also, in patients with cholelithiasis, both the SEP traces evoked by T7 direct intercostal nerve stimulation and those evoked by “Gall bladder” auricular point stimulation were altered in the same manner. These results demonstrate that there is correlation between the activation of specific areas of brain cortex and stimulation of their corresponding auricular acupuncture points, and indicate a convergence into the same cortical somatosensory area of nerve impulses coming from the body organ itself and from the auricular point corresponding to that organ. This might be taken as suggesting neurological support for a functional somatic relationship of auricular points.