Drawing from childhood experience: constructional apraxia and the production of oblique lines.

We report the performance of two patients (ECR and RA) with constructional apraxia on a drawing task previously used to test the development of planning abilities in children. Patients and controls were required to produce both oblique and horizontal/vertical lines that formed a right angle. Planning demands were manipulated across conditions by providing additional spatial information to constrain the drawing. Both patients produced drawings that were less accurate than controls. In addition, ECR was particularly poor at producing oblique lines compared to both RA and controls, even under conditions with minimal planning demands. This pattern of performance is qualitatively similar to that of children under eight years (see Broderick and Laszlo, 1988). Taken together these results provide further evidence that constructional apraxia is not a unitary disorder (with differential performance between patients) and that those differences are not necessarily related to laterality of damage (as both patients had right-hemisphere lesions). We argue for a more quantitative approach to the study of drawing abilities in neuropsychological testing in order to facilitate a finer grained analysis of the disorder and of comparison between patients.