In the early stages of Alzheimer's disease (AD) motor and cognitive dysfunctions has been observed.

In previous studies we have shown that AD patients present abnormalities of selected graphomotor skills, but results were vary and not conclusive. In this study, we conducted more extensive tests on a larger study group.

The aim of the study is to identify which graphomotor functions are impaired in the early stages of AD.

Seventy-one patients with mild and moderate AD (F.00.0, F.00.1, F.00.2) (MMSE 20.3 ± 3.8; age 79.1 ± 5.21) were examined. Forty-four healthy ones (C) without symptoms of dementia, matched for demographic characteristics (MMSE 29 ± 1.1; age 78.3 ± 4.7) were examined. Graphomotor skills were assessed by the original drawing test (the eight figures and the signature) performed in a magnetic field (resolution 2540 dpi and 1024 pressure levels). These test were implemented on a graphic tablet (Wacom Intuos) with the specialized software. The length and time of drawing, the average and maximum speed of drawing, the average and maximum momentary speed, the amplitude and frequency (with FFT spectrum analysis) of hand tremors were measured.

Statistical analysis of the graphomotor signal revealed differences between the AD group and the C group with respect to various parameters. The largest differences have been observed in partially automated skills such as signature, and not drawing shapes (lines, spiral, etc.). The average speed of signature and maximum momentary speed of signature is lower in the AD group.

This method allows for quantitative and objective measurement of the biophysical signal and assessment of the graphomotor skills.

The authors have not supplied their declaration of competing interest.