Fig 1.
Digitized spiral analysis equipment and radius-angle transformation in spiral analysis.
Digitized spiral analysis equipment (left) and radius-angle transformations from an ideal spiral (top row) and a PD patient (bottom row). The radius-angle transformation is the mathematical equivalent of “unraveling” the spiral such that the original two-dimensional graphic features, represented by (x, y) coordinates, are maintained with fidelity and expressed linearly in terms of (r, θ) coordinates. The example black dot shown is three full cycles (6 π radians) into each of the spiral drawings. In comparison to the ideal spiral straight transform, note the varying and irregular relationship between the radius and drawing cycles in the PD spiral.
Table 1.
Demographic characteristics.
Fig 2.
Spiral analysis indices in PD and controls.
*p<0.05, mean spiral values presented except for SWVI (median).
Table 2.
Dominant-hand Spiral Indices and Dominant–Non-dominant differences for PD Subjects and Controls.