There is pulse wave information widely known for the pulse oximeter besides Hb change as one of the biological information acquired by NIRS (Near-Infrared Spectroscopy) associated with the change of extinction characteristics of hemoglobin.
 Conventionally, in the world of optical brain function imaging, the research has progressed focusing on the Hb change in brain localization.The pulse wave signal in a brain localization is very weak compared with Hb change and a good SNR (signal to noise ratio) has not been obtained, therefore it has not been used in spite of a possibly useful information.
 Spectratech has newly worked on this subject. All the basic parts are newly designed further enhancing our own technology of the spectrum spread modulation. Furthermore, the "Ultrahigh SNR technology" was established in addition to the functions of the existing Spectratech OEG-16. It could reach a level at which even a multi-channel analysis of ultraweak pulse wave of a brain localization is possible.
 Spectratech offers the new index of Apprent SpO2 (Apparent arterial oxygen saturation) this time so that it will be of some help for the researches still more deeply from cerebral circulation/metabolism to brain function. Of course, it is a state where the measuring equipment is just prepared as a foundation now. It is hoped that the brain function research will be deepened further by measuring Apparent SpO2 and the pulse wave change simultaneously besides the conventional hemoglobin change as well as you, the researchers will research from various angles, and kindly advise us.