An implantable medical device for releasing therapeutic agent having a medical device body and a plurality of reservoir-defining structures disposed on a surface of the body. The imaging device causes the captured image data and the time spatial parameter corresponding thereto to be stored in the storage server, andor to be recorded on the recording medium. The grip-mounted, pressure-responsive switch unit includes a resilient first switch strip and a resilient second switch strip. In an embodiment, user settings are adjusted on an ongoing basis in response to input device events.