An exemplary method includes emitting radiation subcutaneously; sensing at least some of the emitted radiation as reflected cutaneously; detecting an abnormal physiologic condition; and, based at least in part on the sensing, adjusting a stimulation therapy to treat the detected abnormal condition. In such a method, the abnormal condition may be an abnormal cardiac condition, an abnormal neural condition or other condition. Various other methods, devices, systems, etc., are also disclosed.