This study characterizes the sensitivity of noninvasive measurements of cerebral blood flow (CBF) by using frequency-domain near-infrared spectroscopy (FD-NIRS) and coherent hemodynamics spectroscopy (CHS).
Thao Pham, Giles Blaney, Angelo Sassaroli, Cristianne Fernandez, and Sergio Fantini, "Sensitivity of frequency-domain optical measurements to brain hemodynamics: simulations and human study of cerebral blood flow during hypercapnia," Biomed. Opt. Express 12, 766-789 (2021)