RESUMO
Objective: Acupressure applied on the Extra-1 (Yintang) point decreases bispectral index (BIS) values and stress in healthy volunteers. The current authors hypothesized that acupressure and/or acupuncture could alter regional cerebral oxygenation as expressed by middle cerebral-artery velocity. This study was conducted to test that hypothesis. Materials and Methods: After giving written informed consent, healthy volunteers received, randomly, (1) acupressure on the Extra-1 (Yintang) point, (2) acupressure on a sham point lying 2 cm over the lateral end of the right eyebrow, (3) no acupressure, or (4) modified manual acupuncture on the Extra-1 (Yintang) point. Each intervention lasted 10 minutes, except for acupuncture, which lasted for 20 minutes. The flow velocity of the left middle cerebral artery-as expressed by the Pulsatility Index (PI), heart rate (HR), and hemoglobin oxygen saturation (SpO2)-was recorded before each intervention, every 2 minutes during the intervention, and 10 and 70 minutes after the end of the intervention. A 2-MHz hand-held probe of a transcranial Doppler system (Companion II Micro TCD Nikolet Biomedical Inc., Madison, WI) was used to isolate the left middle cerebral artery via a transtemporal approach. Results: There was no difference among the four interventions at any timepoint in PI (P = 0.431; F = 0.929), HR (P = 0.948; F = 0.121), and SpO2 (P = 0.708; F = 0.465), as well as in systolic arterial pressure (P = 0.857; F = 0.255) or diastolic arterial pressure (P = 0.991; F = 0.036). Conclusions: There were no changes in PI measurements when acupuncture or acupressure was applied on the Extra-1 (Yintang) point once and for a limited time duration.
