1. An apparatus comprising: a processor circuit, configured to obtain a first multidimensional vector, comprising dimensions corresponding to respective first conductivity characteristics obtained from different implantable electrode configurations associated with a subject; obtain a second multidimensional vector space or vector, comprising dimensions corresponding to respective second conductivity characteristics obtained from the different electrode configurations associated with the same or a different subject, wherein the first conductivity characteristics are of the same type as the second conductivity characteristics, and wherein the different electrode configurations corresponding to the respective dimensions of the first multidimensional vector are of the same type as the different electrode configurations corresponding to the respective dimensions of the second multidimensional vector space or vector; and providing a physiological status indicator obtained at least in part by performing a vector comparison that determines proximity of the first multidimensional vector to the second multidimensional vector space or vector.