SELECTIVE LOSS OF VERBAL IMAGERY

This single case study of the ability to generate verbal and non-verba l imagery in a woman who sustained a gunshot wound to the brain report s a significant difficulty in generating images of word shapes but not a significant problem in generating object images. Further dissociati on, however, was observed in her ability to generate images of living vs non-living material. She made more errors in imagery and factual in formation tasks for non-living items than for living items. This patte rn contrasts with our previous report of the agnosic patient, M.S., wh o had severe difficulty in generating images of living material, where as his ability to image the shape of words was comparable to that of n ormal control subjects. Furthermore, with regard to the generation of images of living compared with non-living material, M.S. shows more er rors with living than nonliving items. In contrast, the present patien t, S.M., made significantly more errors with non-living relative to li ving items. There appear to be two types of double dissociation which reinforce the growing evidence of dissociable impairments in the abili ty to generate images for different types of verbal and non-verbal mat erial. Such dissociations, presumably related to sensory and cognitive processing demands, address the problem of the neural basis of imager y.