Early-latency Somatosensory Evoked Potentials Elicited by Electrical Acupuncture after Needling Acupoint LI-4

Abstract

The stimulating methods of prior studies on somatosensory evoked potentials (SEPs) elicited by acupoint stimulus had involved surface electrodes, while the clinical practice of acupuncture is mostly performed by inserting the acupuncture needle inside the body. Clinical observations show that there are often some special sensations when LI-4 is needled. To observe if the SEPs produced by acupoint acupuncture had a distinguishing property, we studied the SEPs elicited by electrical acupuncture after the acupuncture needle was inserted into LI-4 and its control point, and then mapped them with the 128-channel Electric Brain Signal Image system. We also compared this to SEPs by median nerve stimuli. Results showed that the most interesting finding was the marked differences of N1-P1 and N2-P2 amplitude between SEPs at LI-4 (SEP-LI) and its control point (SEP-CP), which were in the opposite direction. Marked differences were also found between latencies and amplitudes of the SEPs elicited by acupuncture and by median nerve stimulus (SEP-M). The differences between SEP-LI and SEP-CP might be due to the additional effects of the activation of nerve endings and muscle spindles in LI-4 to the SEPs formed by the activation of superficial and deep radial nerves during electrical acupuncture. The differences between SEPs to acupoint and median nerve stimuli might be mainly due to the different distances from the stimulated regions to the cerebral cortex, the diversity and the number of activated fibers.

Needling of the Extra 1 Point Decreases BIS Values and Preoperative Anxiety

“…Acupuncture suppresses the amplitude and the latencies of somatosensory evoked potentials (SEP) (Xu et al, 1993) and differences in amplitude and latencies of the SEPs between acupuncture and control points have been demonstrated (Wei et al, 2000). Regarding the electroencephalogram (EEG), some investigators reported an increase in the EEG power in all frequency bands after acupuncture (Tanaka et al, 2002;Xu et al, 1998), while others failed to show an effect (Rosted et al, 2001).…”

Effects of Verum Acupuncture Compared to Placebo Acupuncture on Quantitative EEG and Heart Rate Variability in Healthy Volunteers

“…The results of the present study confirmed the previous findings that acupuncture in a specific manner can significantly change cerebral EEG parameters as shown by different authors. 9,27 In parallel with ␣1 increase during VA, LI4-stimulation led to more pronounced pain-sensation compared to PA, as well as more incidents of specific de qi sensations, which are a part of the concept of acupuncture. The fact that pain and de qi sensations occurred also in some volunteers during PA might be explained by activation of nociceptors during needle pressure at the skin or by expectation in sense of a placebo effect.…”

Development of acupuncture-reading with EEG, MRI and PET

“…The objective of Dr Chen ZH's [4] group is to study the effects of electro-acupuncture on electroencephalography in vascular dementia (VD) patients. According to the Hasegawa dementia scale (HDS), the 46 VD patients were classified into three grades and divided into the EA group and the nimotop group randomly.…”