Kinematic Analyses of Graphomotor Functions in Individuals with Alzheimer's Disease and Amnestic Mild Cognitive Impairment

This study explores the clinical features and motor impairments, characterized using computerized graphomotor analysis, of individuals with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). We recruited 20 participants with AD, 12 with aMCI, and 16 control participants. All participants were asked to perform six graphomotor tasks on a digitizer tablet: formation of straight lines, cursive-connected loops, a single circle, and continuous circles, and two aiming tasks. The results show that slowness and irregularity of movement of AD and aMCI patients were not present in all tasks. Impairment was not found in the straight lines and cursive-connected loops tasks. In the task of drawing a single circle, the AD and aMCI participants had more difficulty drawing perfect circles than did the control group. They also showed greater size variations when drawing continuous circles. In the aiming tasks, performance differed across the three groups. The AD and aMCI participants both performed more slowly than did the controls. When accuracy was specified, the AD and aMCI participants performed the graphomotor tasks requiring wrist and finger coordination more slowly than did the controls. The results of this study suggest that aMCI is characterized by motor dysfunction and cognitive impairment. The degree of motor impairment, particularly in aiming movements with accuracy constraints, may help identify those at risk for AD.