Systems and methods for detecting and/or treating nervous system disorders, such as seizures. Certain embodiments of the invention relate generally to implantable medical devices (IMDs) adapted to detect and treat nervous system disorders in patients with an IMD. Certain embodiments of the invention include detection of seizures based upon comparisons of long-term and short-term representations of physiological signals. Further embodiments of the invention include preparing for the delivery of therapy by warming up therapy delivery components prior to the expected delivery of therapy.