Circle Drawing as an Objective Indicator of Handedness

Past research has indicated that the dominant arm produces more efficient interactive torque control during multi-joint movements. In addition, a bimanual arm movement study found that the dominant arm produced more circular trajectories during circular drawing movements, particularly during fast speed conditions. The current study serves to determine whether statistical trajectory analysis of circular drawing patterns can be used as an objective indicator of handedness. The experiment involved subjects performing unimanual circle drawing movements in both arms at two different speeds. The subjects were given handedness questionnaires to separate them into Right-Handed, Left-Handed, and Mixed-Handed categories for data analysis. The movements were tracked by optoelectronic cameras, and a paired T-test comparing the trajectories in each arm established statistical differences in performance. Right-Handed subjects had significant differences in the trajectories of each arm in which the right arm movements produced more circular trajectories. This was more pronounced in fast movements. Left-Handed subjects had no significant differences among arms in movements of either speed, likely due to a low sample size, although the trend in the fast conditions was that the left arm movements were more circular. Mixed-Handed subjects tended to produce more circular trajectories in right arm movements, which reached statistical significance in both conditions. These results indicate that this test could potentially be used as an objective measure of handedness, but more research with stronger statistical significance according to the hypotheses would need to be conducted to confirm the trends observed.