Similar suport is found with brain injured patients. E.G., PV shoes a number of specific impairments indicating a special problem with rehearsal, and not specifically with the phonological buffer. Instead, the visuospatial buffer is assumed to be used for this kind of information. It is similar to Kosslyn's use of executive processing to convert propositional information into spatial. Again, the move is to functional dissociations.
PET studies offer support too.
PET reveals left hemisphere sites, including Broca's area, the frontal lobe, and the left parietal lobe, light up for this task. One hypothesis consistent with these activation sites is that subjects create a mental image of the dot locations, using processes of the occipital lobe. They encode the locations of the dots from this image using processes of the parietal lobe, and they then store these encoded locations using frontal mechanisms. Single cell recording techniques have also been used successfully. Evidence suggests that individual cells appear to be used as memories for specific spatial locations.