1. A system comprising: a behind-the-ear signal processing unit housed within a single casing and configured to be located external to a cochlear implant patient, the behind-the-ear signal processing unit comprising a port and further configured to generate one or more stimulation parameters defining a stimulation current applied to a cochlea of the cochlear implant patient via one or more implanted electrodes; and one or more external electrodes configured to be removably coupled directly to the port of the behind-the-ear signal processing unit; wherein the behind-the-ear signal processing unit is further configured to use the one or more external electrodes removably coupled directly to the port of the behind-the-ear signal processing unit to detect one or more central auditory potentials generated in response to the stimulation current applied to the cochlea of the cochlear implant patient via the one or more implanted electrodes, and process the detected one or more central auditory potentials.