Many suggestions have been made as to the most appropriate tests for the selection of patients for cochlear implantation. One of the most appropriate tests when selecting patients for a round window extracochlear device is stimulation of the round window itself by a temporary electrode of the same size. Fourteen patients have been tested, 7 of whom were judged to have a good response to electrical stimulation. Six patients have gone on to permanent implantation with a round window cochlear implant.