Drawing Direction Effect on a Task’s Performance Characteristics among People with Essential Tremor

Abstract

Essential tremor (ET) is a common movement disorder affecting the performance of various daily tasks, including drawing. While spiral-drawing task characteristics have been described among patients with ET, research about the significance of the drawing direction of both spiral and lines tasks on the performance process is scarce. This study mapped inter-group differences between people with ET and controls related to drawing directions and the intra-effect of the drawing directions on the tremor level among people with ET. Twenty participants with ET and eighteen without ET drew spirals and vertical and horizontal lines on a digitizer with an inking pen. Time-based outcome measures were gathered to address the effect of the drawing directions on tremor by analyzing various spiral sections and comparing vertical and horizontal lines. Significant group differences were found in deviation of the spiral radius from a filtered radius curve and in deviation of the distance curve from a filtered curve for both line types. Significant differences were found between defined horizontal and vertical spiral sections within each group and between both line types within the ET group. A significant correlation was found between spiral and vertical line deviations from filtered curve outcome measures. Achieving objective measures about the significance of drawing directions on actual performance may support the clinical evaluation of people with ET toward developing future intervention methods for improving their functional abilities.

Does Cup-Grip Type Affect Tremor among People with Essential Tremor?

“…Participants were at least 20 years old and recruited from the general population by advertisements in social media and bulletin boards. Participants in the ET and control group were the same sample used in previous studies [ 15 , 19 ] (one study without the control group [ 19 ]).…”

“…Participants were asked to draw a spiral between lines of a predrawn spiral with an interloop width of 1.5 cm. For more details, refer to [ 15 ].…”

“…Our analysis of data from the digital graphic board included normalized SSE of defined outcome measures, computed as the radial and distance curve deviation from a filtered curve (LPF of 4 Hz) [ 15 ]. To check the sensitivity of results for the chosen cutoff frequency, we also analyzed the grip-type comparison results for 3 Hz cutoff frequency.…”

“…Previous research using such measurement systems included various ADL tasks, such as writing; drawing; pouring, drinking from, or holding a cup; using a spoon, computer mouse, keyboard, or remote control; and folding laundry [ 7 , 9 , 11 , 12 , 13 , 14 ]. Some research implemented accelerometer measurement tools to evaluate the tools’ ability to characterize the tremor and its severity [ 11 ], or to validate tremor scales [ 7 ], whereas others used graphical boards to evaluate the effects of task characteristics such as drawing direction [ 15 ].…”

“…The first part of the study addressed self-reported disability caused by ET and modifications that participants with ET implemented to decrease the tremor [ 19 ], using the Columbia University Assessment of Disability in Essential Tremor (CADET) disability questionnaire [ 6 , 7 ]. The second part addressed the effect of drawing direction on task-performance characteristics while drawing lines and spirals on a computer digitizer [ 15 ] among participants with ET compared to controls. In the research reported herein, we focused on the effects of the task characteristics on a chosen daily task.…”