Exploring constructional deficits in neglect: A paradoxical phenomenon?

Many neglect patients omit lefi-sided elements i drawing. Recenl studies ascribe this behaviour to a strong engagement of atlentional mechanisms to the right part of the stimulus or to a difficulty iii disengaging attention from the right side. Alternative interpretations could hypothesize a defective mental representation of the left hemi-space. To test this possibility we have set up an investigation of drawing abilities in neglect patients with focal right hemispheric lesions, without diffuse cognitive impairment. Early findings in patients without overt constructional disabilities revealed an apparently paradoxical phenomenon. All patients tended to bisect horizontally-aligned segments and rectangles with a right ward bias; however, when patients had to copy rectangles divided into two halves, they drew shorter left parts and longer right parts respect to normal controls, with a leftward displacement of stimuli's midline. These\findings are discussed in the light of the hypothesis, of a defect in mental representation of space.