A new near-infrared spectroscopy system for detection of hemoglobin and water concentration changes during a human activity

Recent advancements in the field of neuroscience have demonstrated that near-infrared spectroscopy (NIRS) has been widely used to measure the concentration changes in the blood chromophores during an activity. Unlike the other imaging methodologies, NIRS system can be constructed low cost, portable and easy to use. Water possess about 80% of the blood chromophores, so it is important to find out the effect of water concentration change during an human body activity In this paper, we have developed a wireless NIRS system that not only determine the concentration change of oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) but it can also find out the concentration change of water (H₂O). Our wireless system is composed of a microcontroller, an optical probe, tri-wavelength light emitting diodes (LEDs), photodiodes, WiFi communication module and battery. To test the functionality of the system, arterial occlusion experiment was performed over a male healthy subject. During the experiment, NIRS system showed the corresponding hemoglobin change and water concentration change. Results show that there is no change in the H₂O concentration during the occlusion period but after the blood is released again water concentration increases.