AUTHOR=Toffoli Simone , Lunardini Francesca , Parati Monica , Gallotta Matteo , De Maria Beatrice , Longoni Luca , Dell'Anna Maria Elisabetta , Ferrante Simona 

TITLE=Spiral drawing analysis with a smart ink pen to identify Parkinson's disease fine motor deficits

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1093690

DOI=10.3389/fneur.2023.1093690

ISSN=1664-2295

ABSTRACT=INTRODUCTION: Since the uptake of digitizers, quantitative spiral drawing assessment allowed gaining insight into motor impairments related to Parkinson’s Disease. However, the reduced naturalness of the gesture and the poor user-friendliness of the data acquisition hamper the adoption of such technologies in the clinical practice. To overcome such limitations, we present a novel smart ink pen for spiral drawing assessment, intending to better characterize Parkinson’s Disease motor symptoms. The device, used on paper as a normal pen, is enriched with motion and force sensors. 
METHODS: 45 indicators were computed from spirals acquired from 29 Parkinsonian patients and 29 age-matched controls. We investigated between-group differences and correlations with clinical scores. We applied machine learning classification models to test the indicators ability to discriminate between groups, with a focus on model interpretability.
RESULTS: Compared to control, patients’ drawings were characterized by reduced fluency and lower but more variable applied force, while tremor occurrence was reflected in kinematic spectral peaks selectively concentrated in the 4-7Hz band. The indicators revealed aspects of the disease not captured by simple trace inspection, nor by the clinical scales, which, indeed, correlate moderately. The classification achieved 94.38% accuracy, with indicators related to fluency and power distribution emerging as the most important.
CONCLUSION: Indicators were able to significantly identify Parkinson’s Disease motor symptoms. Our findings support the introduction of the smart ink pen as a time-efficient tool to juxtapose the clinical assessment with quantitative information, without changing the way the classical examination is performed.