Effect of acupuncture stimulation of the auricular sympathetic point on evoked sudomotor response

To investigate whether stimulation of the auricular sympathetic acupuncture point would affect the mean maximum amplitude of evoked sudomotor responses.

A placebo-controlled trial. Two types of controls were used: no acupuncture and acupuncture of an alternate "non-sympathetic nervous system" related (i.e., a non-sympathetic, placebo) point. Subjects were included in either the placebo or the test group. Each subject would have one session of acupuncture and one session without acupuncture, the acupuncture was applied in either the first or the second session. Initially, each group was unaware in which of the two sessions they would receive acupuncture (cross-over design). Each individual was unaware of which group they were to participate in.

A quiet, sealed room with a constant temperature, in the research department of the Anglo-European College of Chiropractic.

Thirty-eight asymptomatic male, white volunteers (18 to 40 years old).

The two groups underwent two electrodermal response (EDR) recording sessions, at an interval of 5 weeks. During each session, they were also presented with eight stimuli, each of which was designed to stimulate the sympathetic nervous system. In each session, subjects either received auricular acupuncture (AA) or did not.

The maximum amplitude of the EDR for each stimulus.

AA at the non-sympathetic, placebo point significantly increased EDR both with respect to the individual stimuli (p < or = 0.05 to < or = 0.001) and for the pooled data (p = 0.0001). AA to the sympathetic point produced no significant change in EDR for either individual stimuli (p range > or = 0.8 to > or = 0.1) or for the pooled data (p > 0.8). A significant difference was found between the results from placebo and sympathetic point stimulated groups during AA for 2 of the 8 stimuli (p < 0.05), and for the pooled data from all 8 stimuli (p = 0.0006).

Stimulation of the sympathetic AA point significantly decreased the stimulus-evoked EDR when compared with an AA stimulation to a non-sympathetic (placebo) point. However, it did not significantly alter EDR compared with no treatment. This implies that the increase in response as a result of inserting the needles was negated by placing the electrodes in the AA sympathetic point. Consequently, one might surmise that there may be a specific action of AA in respect to hyperhidrosis resulting from an increase in sympathetic activity.