Healthy young participants deviate leftward when bisecting horizontal lines and upward when bisecting vertical lines. This upward deviation increases with age while leftward deviation may decrease or even reverse with age. The clock-drawing test is used to assess patients’ cognitive functions and it may be that, with clock drawing, older adults reveal a deviation in estimation of the center of the clock.

Participant data were acquired retrospectively from nondemented older adults who had been assessed with neuroimaging, a comprehensive neuropsychological protocol, and digital clock drawing using digital pen technology from Anoto, Inc. The estimated center of the circle constructed by each participant was determined by the point where the hands of the clock converged. One sample t-tests were used to determine whether horizontal and vertical deviations of this estimated center from the actual center were significant. Linear regression was performed to examine whether this deviation was affected by age.

Participants consisted of 160 older adults (age range 55-85, mean = 69, SD = 6; years of education mean = 16, SD = 3; 55% female). Hand convergence deviated significantly upward from the clock midpoint (mean = 1.68mm, SD = 3.88mm, p<0.001). There was a small leftward deviation which was not significant (mean = 0.14mm, SD = 2.35mm, p=0.451). On linear regression analysis, there was no association between age and horizontal deviation (F(1,158 = 0.071, p = 0.510, R2 = 0.001)) or vertical deviation (F(1,158 = 0.597, p = 0.791, R2 < 0.001)).