A system for monitoring brain activity of a subject, including an implantable measurement device including: a sensor configured to measure electrical activity in the brain; electronic measurement processing devices configured to: receive measurement data from the sensor; use the measurement data to determine if the brain activity of the subject is indicative of an event; and generate event data indicative of the brain activity associated with the event; and an implantable transceiver configured to transmit the event data; an inductive implantable coil configured to inductively receive power; and an external monitoring device including: an external transceiver configured to receive event data from the implantable measurement device; an inductive external coil configured to inductively transmit power to the implantable measurement device; and electronic monitoring processing devices configured to: generate subject data; and transfer the subject data to analysis processing devices for analysis.