DRAWING WITH THE NONDOMINANT HAND - IMPLICATIONS FOR THE STUDY OF CONSTRUCTION

Background: Constructional impairment following left vs. right hemisph ere damage has been extensively studied using drawing tasks. A confoun ding factor in these studies is that right-handed patients with left h emisphere damage (LND) are often forced by weakness to use their nan-d ominant (left) hand or hemiparetic dominant hand. Qualitative differen ces in the drawing characteristics of left and right hand drawings by normal subjects have not previously been characterized. The present st udy was undertaken to determine the qualitative differences between le ft and right hand drawings of normal subjects. Methods: Thirty right-h anded, elderly subjects without a history of neurological disease were asked to draw, from memory, seven objects using the right and left ha nd. Waif of the subjects were randomly assigned to draw with the left hand first, and half the right hand first. Right and left hand drawing s were compared using a standardized scoring system utilized in severa l previous studies of drawing in focal and diffuse neurological diseas e, Each drawing was scored on eighteen criteria. Right and left hand d rawing scores were then compared using the t-test for paired samples o r the Wilcoxon matched-pairs test. Results: Drawings made using the le ft hand were found to be significantly simpler, more tremulous and of poorer overall quality than drawings made by the same subjects using t he right hand. Conclusions: The deficits found in left versus right ha nd drawings of normals are similar to those found in patients with LHD , suggesting that much of the drawing impairment seen following LHD is due to an elementary motor disturbance related to use of the non-domi nant hand.