ABSTRACT
We tested 125 normal subjects and 24 right and 22 left focal brain-damaged patients (RBD and LBD) on the Rey figure copying test and on a battery of perceptual and representational visuospatial tasks, in search of relationships between constructional and visuospatial abilities. Selected RBD and LBD were not affected by severe aphasia, unilateral spatial neglect or general intellectual defects. Both RBD and LBD showed defective performances on the constructional task with respect to normal subjects. As regards visuospatial tasks, both patient groups scored lower than normal subjects in judging angle width and mentally assembling geometrical figures; moreover, RBD, but not LBD, achieved scores significantly lower than healthy controls in judging line orientation and analyzing geometrical figures. Post-hoc comparisons did not reveal any significant differences between RBD and LBD. Multiple regression analysis showed that visuospatial abilities correlate with accuracy in copying geometrical drawings in normal subjects and in RBD, but not in LBD. From a theoretical perspective, these findings support the idea that visual perceptual and representational abilities do play a role in constructional skills.
Subject(s)
Brain Damage, Chronic/psychology , Neuropsychological Tests , Space Perception/physiology , Visual Perception/physiology , Aged , Aging/psychology , Brain Ischemia/psychology , Education , Female , Form Perception/physiology , Functional Laterality/physiology , Humans , Imagination/physiology , Intracranial Hemorrhages/psychology , Male , Memory/physiology , Psychomotor Performance/physiology , Regression Analysis , RotationABSTRACT
We describe a patient with an ischemic right frontal lesion and mild left neglect who showed a systematic tendency to transpose drawings on one side of the page, which varied depending on the starting point (left or right) of his graphic productions. When not specifically cued, the patient started to draw in the ipsilesional (right) side and tended to show allochiria on the right, but occasionally, or under specific instructions, the patient started drawing from the left side and then showed a complete reversion of his spatial transpositions. To clarify the basic mechanisms underlying such a peculiar constructional phenomenon, we performed a series of experimental investigations, including extended copying tasks, a clock-marking test (to mark the position of single hours on a clock-face), and a line bisection task with progressive left-toright or right-to-left stimulus presentation. Findings suggested that "alternating" allochiria in copying and drawing from memory tasks is an epiphenomenon of a basic inability to move attention and action away from the starting point of graphic productions. The present case study, contrasted with observations on other brain-damaged patients, demonstrates that allochiria may have different neuro-cognitive bases and offers new insights for theoretical interpretations of unilateral spatial neglect.
