I will review recent diffuse optics experiments carried out at PENN which explore cerebral hemodynamics in a variety of patient populations. Generally speaking, the research demonstrates the feasibility of both diffuse correlation spectroscopy (DCS), for measurement of cerebral blood flow, and more 'traditional' near-infrared (NIR) measurements of cerebral blood volume and oxygen saturation. The optical methods are employed to assess cerebral responses to simple functional perturbations such as posture change. The optical methodologies are also directly compared to transcranial Doppler Ultrasound (TCD), Xenon-CT and MRI in some of these patient (and normal) populations.