Cancellation of Superficial Blood Flow in Brain Function Measurements Using Near-Infrared Spectroscopy

In brain function measurement by near-infrared spectroscopy, reduction of signal fluctuation caused by the superficial blood flow is necessary. We proposed an equilateral-triangle-type sensor arrangement for cancelling superficial blood flow using short-distance detectors placed at the center of the triangle. We applied the independent components analysis (ICA) for this equilateral triangle configuration to improve the correction effect. We measured the change in blood volume caused by the motion artifacts according to the posture change and analyzed the correction effect of the ICA. It is shown that the ICA is more effective than simple subtraction and has small dependence on the measurement conditions and is applicable to this equilateral triangle configuration.