Pressure applied on the extra 1 acupuncture point reduces bispectral index values and stress in volunteers. 
We investigated the effect of pressure application on the acupuncture point "extra 1" and on a control point on the bispectral index (BIS) values and on stress in 25 volunteers.  In each volunteer, pressure was applied on the extra 1 point for 10 min and on a control point for 5 min on different days and in a randomized manner.  The BIS value was recorded before applying pressure on the extra 1 point, during pressure application every 30 s for 10 min, and after pressure release.  Regarding the control point, BIS values were recorded for 5 instead of 10 min during pressure application because acupressure on that point was associated with an unpleasant feeling.  Each volunteer was asked to score stress before and after pressure application from 0 to 10.  The BIS values were significantly reduced 2.5, 5, 7.5, and 10 min during pressure application on the extra 1 point (P < 0.001 for each comparison, respectively) and returned to the baseline values after pressure release.  Pressure application on the control point decreased BIS values (P < 0.01 and P < 0.05 at 2.5 and 5 min, respectively).  However, these values were maintained close to 90% and were significantly higher than those obtained during pressure on the extra 1 point (P < 0.001 and P < 0.001 for the 2.5- and 5-min comparisons).  The verbal sedation score values obtained after pressure application on the extra 1 point were also lower when compared with the values obtained after pressure application on the control point (P < 0.001).  This crossover study investigated the effect of pressure application on the acupuncture "extra 1" point in healthy volunteers.  Acupressure applied for 10 min on the extra 1 point significantly reduced the BIS values and the verbal stress score when compared with acupressure applied on a control point.