Experimental approach to the validity of the hemodynamics extraction method for high resolution near-infrared spectroscopy

Abstract

For decades, the near-infrared spectroscopy (NIRS) is widely used for a method of non-invasive monitoring to brain. Despite the NIRS have advantages in the feasibility of conversion as portable device and good temporal resolution than other brain reading modalities, its poor spatial resolution of a few centimeters is a critical disadvantage, but it is not easy to be overcome due to the physical characteristics of the NIRS. Given the HEM could improve a spatial resolution of the NIRS as 1cm, but a validity of it was not verified perfectly. Therefore, trying to determine it by experimental approaches in this research. Prior to the experiments because an implementation of adequate system of HEM is considered more im-portant task, I implemented the NIRS system composed of Printed Circuit Board (PCB), headset and S/W. This system satisfied targeted specification and desired arrangement of source-detector could be possible by removable custom-made optode module. Trying to determine the validity of the HEM by a quantitative comparison of between results of conven-tional measure method and the HEM using proposed source-detector structure, but it is improper approach due to time-varying result. In conclusion, I comforted that the scalp effect is a dominant obstacle of NIRS measurement by various experiments and that the assumption of the HEM is valid after a cancellation of the scalp effect.