Near Infrared Spectroscopy (NIRS), which is a non-invasive optical technique detecting oxy- and deoxy-hemoglobin, has been used to monitor cerebral blood perfusion level during +Gz exposure. In our previous study, we established a method for in-flight monitoring of cerebral oxygen status using NIRS.
Lately, NIRS device has become small and light, so in this study, we developed “wearable NIRS” sensor integrated helmet to monitor in-flight cerebral oxygenation status.
We recruited 5 healthy male participants in this study. Each participant was exposed to gradual onset run (GOR, 0.1G/sec) and to sequential 4G, 4.5G and 5G 15sec plateau rapid onset runs (ROR, 1.0G/sec). NIRS data were recorded at the left part of forehead using the sensor integrated helmet and at the right side of forehead using conventional NIRS sensor, simultaneously. The significant correlations were observed between the two methods in all +Gz exposure. However, in 2 participants, sensor integrated helmet showed lower signal responses than the conventional NIRS sensor.
We showed that the newly developed “Wearable NIRS” system is fairly comparable to conventional NIRS sensor. For in-flight monitoring of cerebral oxygenation status with fidelity, further improvement in helmet fitting and maintaining sensor position during +Gz exposures is needed.