Human scalp and brain blood flow SCOS sensitivities via superficial temporal artery occlusion

We present a non-invasive, multi-channel speckle contrast optical spectroscopy (SCOS) system for simultaneously measuring scalp and brain blood flow. By using seven source-detector separation channels, our SCOS system targets different tissue depths to separate scalp and brain signals. To validate this depth sensitivity, we applied a temporary occlusion of the superficial temporal artery—affecting only the scalp—and observed significant reductions in scalp-sensitive channels, with minimal change in brain-sensitive channels. Results from 20 human subjects demonstrated the ability to distinguish scalp and brain blood dynamics. This approach is a first experimental evaluation of SCOS systems capabilities to non-invasively probe cerebral hemodynamics, with potential applications in stroke, brain injury, and neurological monitoring.