CHANGES in spatial orientation after brain damage in man have been described, but there is little agreement on their interpretation. They may range from loss of such a seemingly simple ability as discrimination of right from left to impairment of such complex achievements as the making and reading of maps. These disturbances seem to hold clues to the nature and neural correlates of awareness of the body and of orientation in the environment. Yet it is not clear whether diverse forms of disorientation affecting the body or extrapersonal space represent different aspects of some unitary change in function or whether more than one essential alteration has to be assumed. The existence of more than one syndrome might lead one to expect that different aspects of orientation would be selectively vulnerable to lesions in different parts of the brain. If one takes the clinical pictures at their face value, then disorders usually designated as topographical disorientation, loss of topographical memory, constructional apraxia, right-left disorientation, neglect of one half of personal or extrapersonal space, or autotopagnosia may be regarded as separate and independent disturbances, ascribable to different loci of lesion. At the other extreme, they may be considered expressions of a single fundamental defect in spatial organization (Lange, 1930; Stengel, 1944) or in an even more general
Semmes et al. (Tue,) studied this question.