As the propagated sensation along the meridian is a subjective feeling, there is no direct evidence for its presence.

According to a study published in Neural Regeneration Research (Vol. 8, No. 28, 2013), participants with notable propagated sensation along the meridian were given electro-acupuncture at the Jianyu (LI15) acupoint of the large intestine meridian.

When participants stated that the sensation reached the back of their hand, regular nervous system action discharge was examined using a physiological recording electrode placed on the superficial branch of the radial nerve.

When Guangming (GB37) acupoint in the lower limb and Hegu (LI4) acupoint in the upper limb were stimulated, subjects without propagated sensation along the meridian exhibited a high potential reaction in the corresponding area of the brain cortical somatosensory area.

For subjects with a notable propagated sensation along the meridian, the reaction area was larger and extended into the face representative area.

These electrophysiological measures directly prove the existence of propagated sensation along the meridian, and the peripheral stimulated site is consistent with the corresponding primary cortical somatosensory area, which presents a high potential reaction.