Bioengineering assessment of acupuncture, part 5: cerebral near-infrared spectroscopy.

The assessment of cortical activation in the brain due to acupuncture is crucial. Thus far functional assessment of cortical responses to certain external stimuli (for examples, manual needle, optical, electrical) are very few due to the lack of suitable techniques to monitor changes of brain activities. Near-infrared spectroscopy has been found to be suitable for functional studies during acupuncture. By this neuromonitoring method, hemodynamic changes coupled to cortical activity can be monitored. Near-infrared spectroscopy is used to measure regional changes in oxyhemoglobin, deoxyhemoglobin, and cytochrome aa3 noninvasively and continuously. The studies in this fifth part of a review article, which have been carried out mainly by the research group of Biomedical Engineering in Anesthesia and Intensive Care Medicine at the Medical University of Graz, demonstrate that near-infrared spectroscopy is a suitable technique for the assessment of cortical changes in response to varying forms of acupuncture. The method is likely to play an important role in providing new insights into the effects of acupuncture on brain function.