Computerized Screening of Essential Tremor and Level of Severity Using Consumer Tablet

Abstract

Essential tremor (ET) is diagnosed and monitored by movement disorder specialists based on clinical observations. While many ET cases are benign, some require pharmacological and surgical management, and there is a need for tools to assist clinicians in making informed decisions. This work aimed to develop a computerized technique to detect the presence and severity of ET. A set of 6 writing and sketching tasks were performed by 39 subjects on a digital tablet. The position and pressure of contact during the sketching were recorded and analyzed to obtain the dynamics of drawing. ET patients were scored on the Fahn-Tolosa-Marin Tremor Rating Scale by blinded movement disorder neurologists, and then separated into two groups: moderate and severe ET. Drawing tasks were more effective than writing tasks in distinguishing the groups, with drawing horizontal and vertical lines being the most sensitive. A new set of composite index feature was found to be most suitable in separating the three groups, with a Spearman correlation coefficient of 0.72. The technique shows significant differences between controls, patients with moderate tremor and those with severe tremor, with an accuracy of 87.2%. Our computerized analysis significantly outperformed non-specialist clinicians in differentiating ET from control. We conclude that computerized analysis of the dynamics of sketching horizontal and vertical lines is a suitable method to assess the presence and severity of ET.