The Effects of Acupuncture on Cerebral and Muscular Microcirculation: A Systematic Review of Near-Infrared Spectroscopy Studies

Abstract

Acupuncture produces physiological effects via stimulating acupoints, proximal or distal to the region of effect. Near-infrared spectroscopy (NIRS) noninvasively measures tissue-level hemodynamics in real time. We review the literature investigating the effect of acupuncture on muscular and/or cerebral microcirculation. As the basis, we queried PubMed in June 2014 for articles mentioning both acupuncture and NIRS in title/abstract. The reviewed papers investigated either cerebral (n = 11) or muscular hemodynamics (n = 5) and, based on STRICTA for reporting acupuncture methodology, were overall poor in quality. Acupuncture was found to influence regional oxygen saturation in cerebral and muscular tissue. The cortical response in healthy subjects varied across studies. For subjects with stroke or cerebrovascular dementia, findings suggest that acupuncture may modulate dysfunction in cerebral autoregulation. The muscular response to pressure techniques was more intense than that to needling or laser. Probe proximity could impact measurement sensitivity. No one study simultaneously investigated the direct and remote responses. Research utilizing NIRS to investigate the hemodynamics of acupuncture presently lacks in scope and quality. Improved designs, for example, placebo-controlled, randomized trials, and standardized intervention reporting will raise study quality. Exploiting NIRS in clinical settings, such as stroke, migraine, or other pain conditions, is worthwhile.

Effects of Electroacupuncture to the Trigeminal Nerve Area on the Autonomic Nervous System and Cerebral Blood Flow in the Prefrontal Cortex

“…11 A study using near-infrared spectroscopy (NIRS) to investigate acupuncture stimulation noted that MA and LF EA increased cerebral blood flow. 12 On the other hand, another recent study reported that acupuncture stimulation had no impact on cerebral blood flow 13 ; thus, the data are inconsistent in this regard. In addition, the effect of HF EA on cerebral blood flow and autonomic nervous system function and their potential interactions have not been investigated.…”

Contrast Baths, Intramuscular Hemodynamics, and Oxygenation as Monitored by Near-Infrared Spectroscopy

“…24 The unique capabilities of NIRS may thus be relevant in monitoring the effect of physical modalities on tissue hemodynamics and oxygenation. [25][26][27][28] The purpose of our study was to investigate the effects of CB on intramuscular perfusion and oxygenation of the lower leg in healthy individuals using noninvasive NIRS. We hypothesized that by altering local hemodynamics, CB would increase the level of intramuscular oxygenated blood volume.…”

Can Acupuncture Treatment of Hypertension Improve Brain Health? A Mini Review

“…Using NIRS, acupuncture intervention on stroke patients showed a significant increase in regional cerebral blood volume or oxyhemoglobin parameters (Li et al, 2011). A systemic review of NIRS studies indicates that acupuncture varies wildly in healthy adults but seems to be more appropriate for disordered populations such as stroke patients (Lo et al, 2015).…”