A system for monitoring and/or affecting parameters of a patient's body and more particularly to such a system comprised of a system control unit (SCU) and one or more other devices, preferably battery-powered, implanted in the patient's body, i.e., within the envelope defined by the patient's skin. Each such implanted device is configured to be monitored and/or controlled by the SCU via a wireless communication channel. In accordance with the invention, the SCU comprises a programmable unit capable of (1) transmitting commands to at least some of a plurality of implanted devices and (2) receiving data signal from at least some of those implanted devices. In accordance with a preferred embodiment, the system operates in closed loop fashion whereby the commands transmitted by the SCU are dependent, in part, on the content of the data signals received by the SCU. In accordance with the invention, a preferred SCU is similarly implemented as a device capable of being implanted beneath a patient's skin, preferably having an axial dimension of less than 60 mm and a lateral dimension of less than 6 mm. Wireless communication between the SCU and the implanted devices is preferably implemented via a modulated sound signal, AC magnetic field, RF signal, or electric conduction.