Abstract: Implantable medical devices and techniques are implemented that use bio-impedance to measure aspects of patient physiology. A signal separation method is performed at least in part in an implantable device. The method involves detecting a plurality of impedance signals using a plurality of implantable electrodes coupled to the implantable device. The method further involves separating one or more signals from the plurality of impedance signals using a signal separation technique, such as an algorithm-based separation technique.

Abstract: A system and method determines the posture of a body. The system is first calibrated by attaching it to, or implanted it into, a body, placing the body in particular postures, and generating spectral signatures for each of those postures. Thereafter, the system generates spectral signatures for particular instants in time, correlates these instant signatures with the stored signatures, from which the posture of the body at that instant in time is determined.