Changes in cerebral near infrared spectroscopy parameters during manual acupuncture needle stimulation]

Near-infrared spectroscopy (NIRO 300, Hamamatsu Photonics, Japan) was used to monitor human cerebral function in the central region during manual acupuncture needle stimulation of the large intestine 4 (LI.4) point in 16 adult volunteers (9 females, 7 males; mean age 23.9 +/- 6.0 (SD) years, range 19-45 years). We found a significant (p < 0.001) decrease in oxyhaemoglobin after needle insertion and stimulation (duration 20 sec.), accompanied by an increase (p = 0.003) in deoxyhaemoglobin. A repeat stimulation showed similar effects. Cytochrome oxidase aa3 remained unchanged during stimulation. The results demonstrate that near-infrared spectroscopy may be a noninvasive method of measuring regional changes in cerebral haemodynamics resulting from peripheral acupuncture stimulation.