[The control of somesthesia caused by neuroreflex stimulation: quantification of stimulus response as opposed to...

In the reflexotherapy of classical acupuncture it is usually claimed that below a certain level of stimulation, which is determined by the appearance of a peculiar sensation known as De-Qi, no appreciable therapeutic effect is obtained. The control exerted by the afferences over the central nervous system, however, do not work in this way, but instead adjust themselves, albeit with certain peculiarities, to a classical pattern of proportionality between stimulus and response. Our aim is, therefore, to evaluate the extent to which increasingly intense acupuncture stimuli can modify neurophysiological parameters in a way that also grows. We will focus on the quantification on a metametic level, through the study of the F-wave, and in the telencephalon, through somatosensory evoked potentials.

A total number of 21 healthy volunteers were studied and we collected the values corresponding to the parameters indicated in the basal situation, when needling an extra-acupunctural point and following needling of the classical point IG4 until the sensation of De-Qi was felt, and electrostimulation was added after detecting the abovementioned sensation.

We observed a clear progression in the modifications of both the F values and the somesthetic potential, with growing stimuli. Basic inflection does indeed occur after obtaining De-Qi, but on overstimulating from then onwards greater variations are produced. This is especially obvious in the case of the latency of the somesthetic potential. Needling a point that is not on a meridian guarantees that merely piercing the skin does not exert any of the effects mentioned above.

In spite of the classical postulates, it can be observed that the more intense the acupuncture stimulus is, the greater the modifications to the neurophysiological parameters being studied are. The control of the somesthetic afference by acupuncture is something that has already been demonstrated and quantified. What is now seen, in addition, is the direct relation between the intensity of that effect and that of the stimulus used to produce it, which is quite different from the classical conceptions of energy.

The effect of acupuncture stimulation is closely related to the intensity of the stimulus applied; the sensation of De-Qi is not necessary to obtain neurofunctional modifications and stimulations that go beyond it cause greater effects.