Photophlethysmographic changes induced by skin stimulation using acupuncture

The photoplethysmographic signal was recorded, before and then 10 minutes after an acupuncture stimulation, in 46 subjects divided into two groups: group A included 22 cases in which the stimulation was applied at the two classical acupoints SP-6 (Sanyinjiao) and GB-39 (Xuanzhong), and group B included 24 cases in which the stimulation was applied outside the acupuncture zones. A highly significant increase (P < 0.01) of the photoplethysmographic signal after stimulation versus the basal amplitude was observed both in group A (+ 215%, i.e., from 6.50 ± 1.67 mm to 20.47 ± 3.18 mm) and in group B (+ 121%, i.e., from 7.35 ± 1.66 mm to 16.29 ± 1.97 mm)