There is growing evidence about the importance of motor symptoms in psychosis. Motor abnormalities have been observed in naive-drugs, first-episode patients. Clinical assessment of motor abnormalities normally relies upon subjective observer-based ratings. Kinematic analysis of handwriting has proved to be an objective measure of motor symptoms, but it has not been used in clinical settings.

In the present work, the geometrical analysis of handwriting patterns is proposed as a new tool to evaluate motor symptoms in psychosis.

Overall, 35 healthy participants and 43 patients with psychosis from San Agustín Hospital (Linares, Spain) participed in the study. Participants were asked to write with a pen on a white paper (see patterns in the Figure 1). In order to analyze the heterogeneity of handwriting pattterns, we employed lacunarity, a nonlinear measure previously used in the analysis of biomedical images. Lacunarity measures the distribution of gap sizes in a geometrical space. A large value implies large gaps and clumping of points, whereas a small value suggests a uniform distribution with shorter gaps.

Lacunarity was significantly higher in handwritten patterns from patients than in controls. In addition, we found a higher heterogeneity in patients with motor symptoms in comparison with patients without motor symptoms.

Our results suggest that analysis of handwritten patterns can be a valuable method in the evaluation of motor symptoms.

The authors have not supplied their declaration of competing interest.