Objective: The objective was to investigate the effect of three different modes of stimulation on: (1) the electrical conductance of a known acupuncture point (AP) and a point with no known acupuncture function (NP); and (2) the corresponding characteristicvs of de qi sensations. Design: The design was prospective. Settings and Locations: Healthy subjects were recruited for the study at the University of California, San Diego Medical Center. Subjects and Study Interventions: Fifteen subjects were enrolled. Two locations of the subjects’ nondominant hand were marked: (1) AP (Li4); and (2) NP, a control location with no known acupuncture function. The following different stimulation paradigms were applied to the testing sites in a randomized fashion: (1) transcutaneous electrical stimulation via an ECG electrode; (2) manual stimulation via an acupuncture needle; and (3) electrical stimulation via an acupuncture needle. All electrical stimulation was provided at 12 V and 5 Hz for 30 seconds. Outcome Measures: The conductance before and after each stimulation were measured. The subjects were asked to choose four most predominant descriptors of the de qi sensation after the stimulation and to rate the corresponding intensity on a linear VAS. Results: The conductance values at the AP site are generally a bit higher than conductance values at the NP site for each given stimulation type. The de qi VAS score increased significantly after needle electrical stimulation (EA) in comparison to electrode or manual stimulation at both sites. The most predominant (incidence >30%) de qi sensation with electrical stimulation in either electrode or needle electrical stimulation was tingling, whereas in the manual stimulation, aching was the most predominant sensation of de qi. Conclusions: The de qi sensation appears to be qualitatively and quantitatively different between manual and electrical stimulation. The observed difference in transcutaneous electrical conductance betwee

Concurrent applications to the skin of spatially adjacent bands of innocuous warm and cool stimuli would elicit a peculiar sensation, known as the 'thermal grill illusion'. To validate the thermal grill as a research tool, this two-phase study qualitatively characterizes this peculiar sensation and further quantitatively establishes the temperature matching of the most intense/noxious thermal grill stimulations at two different time points. The temperature combinations (degrees C) tested were: 18/18, 42/42, 18/42, 20/20, 40/40, 20/40, 22/22, 38/38, 22/38, 24/24, 36/36 and 24/36. None of the subjects reported pain with single temperature combinations. However, hot associated with pain and burning sensations were reported in all mixed temperature combinations tested. The VAS scores for pain were significantly elevated for 20/40 and 18/42 in comparison to 22/38 and 24/36 (P<0.007). At the 3-second time point, the matching temperatures (+/-SD) of 20/40 and 18/42 were 45.7+/-1.8 (range 44-48) and 46.6+/-1.5 (range 44-48) degrees C, respectively, whereas the matching temperatures for the single temperature combinations were similar to the set temperatures. Importantly, at the 10-second time point, none of the combinations were significantly greater than the highest of the pair of stimuli. The time course variation in the perception of the combined stimuli suggests an adaptation occurred in central processing.