Acupuncture using laser needles modulates brain function: first evidence from functional transcranial Doppler sonography and functional magnetic resonance imaging

Acupuncture using laser needles is a new totally painless stimulation method which has been described for the first time. This paper presents an experimental double-blind study in acupuncture research in healthy volunteers using a new optical stimulation method. We investigated 18 healthy volunteers (mean age±SD: 25.4±4.3 years; range: 21–30 years; 11 female, 7 male) in a randomized controlled cross-over trial using functional multidirectional transcranial ultrasound Doppler sonography (fTCD; n=17) and performed functional magnetic resonance imaging (fMRI) in one volunteer. Stimulation of vision-related acupoints resulted in an increase of mean blood flow velocity in the posterior cerebral artery measured by fTCD [before stimulation (mean±SE): 42.2±2.5; during stimulation: 44.2±2.6; after stimulation: 42.3±2.4 cm/s, n.s.]. Mean blood flow velocity in the middle cerebral artery decreased insignificantly. Significant changes (p<0.05) of brain activity were demonstrated in the occipital and frontal gyrus by fMRI. Optical stimulation using properly adjusted laser needles has the advantage that the stimulation cannot be felt by the patient (painless and no tactile stimulation) and the operator may also be unaware of whether the stimulation system is active. Therefore true double-blind studies in acupuncture research can be performed.