Acupuncture and Acupressure Applied on the Extra-1 ( Yintang ) Acupoint in Healthy Volunteers Do Not Affect Regional Cerebral Blood Flow as Assessed by the Pulsatility Index: A Cohort Observational Study

Abstract

Abstract

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.