In at least one embodiment of a device configured for insertion into a gastrointestinal tract of the present disclosure, the device comprises a core comprising a core material which is solid, semi-solid or compressible, one or more sensors embedded in an interior of the device and/or on a surface of the device, at least one of the one or more sensors configured to obtain a pressure measurement within the gastrointestinal tract and during defecation of the device, and a plurality of electrodes within or upon the device and configured to obtain impedance planimetric measurements within the gastrointestinal tract and during defecation of the device, the impedance planimetric measurements useful to determine cross-sectional areas.