JMIR Publications

ABSTRACT

Background:

The Rey-Osterrieth Complex Figure Test (RCFT) is a neuropsychological test that is widely used to assess visual memory and visuoconstructional deficits in patients with cognitive impairment including Alzheimer’s disease (AD). AD patients have an increased tendency for extraordinary behaviors in the RCFT for selecting the drawing area, organizing the figure, and deciding the order of images, among other activities. However, the conventional scoring system based on pen and paper has limited ability to reflect these detailed behaviors.

Objective:

We aimed to establish a scoring system that addresses not only the spatial arrangement of the finished drawing, but also the drawing process of AD patients by utilizing a digital pen data.

Methods:

A digital pen and tablet was used to copy complex figures. The stroke patterns and kinetics of normal control (NC) and early-onset and late-onset AD patients were analyzed by comparing pen-tip trajectory, spatial arrangement, and similarity of the finished drawings.

Results:

AD patients copied the figure in a more fragmented way with a longer pause (early-onset AD: P = .045, late-onset AD: P = .012). AD patients showed an increased tendency to draw the center zone of the drawing area on top of the target image (early-onset AD: P = .005, late-onset AD: P = .01) with lower accuracy in comparison to the NC group (early-onset AD: P = .004, late-onset AD: P = .002). Early-onset and late-onset AD patients showed similar but slightly different drawing behaviors especially in space usage and in the initial stage of drawing.

Conclusions:

The digitalized complex figure test evaluated copying performance in a quantitative way and further elucidated the patients’ ongoing process during copying. We consider that this novel approach can be used as digital biomarker of AD. In addition, the repeatability of the test will delineate the process of executive functions and constructional organization abilities with disease progression.