A method is provided for identifying a location of a region of interest in a volumetric image scan that includes a plurality of slices of an object and wherein each slice, in turn, includes a plurality of pixels. In at least one embodiment, a first image is determined from the measurement data and pixel values of the first image are modified, by classifying the pixel values in at least three classes, a class pixel value being assigned to each class, and the pixels of the first image being allocated the respective class pixel value. The controller is in electrical communication with, and generates timing and control signals for simultaneously activating, the plurality of signal generators. Each data record has at least one flag associated therewith indicating whether the data record is involved in a modification to the local database by the hearing-impaired user.