Figure 2.

Two illustrative examples of spirals rated as bradykinesia (upper row) and dyskinesia (lower row) by the four raters. The first column shows the actual spiral drawings, the second shows drawing speed over the test trial and the third column shows the high-frequency wavelet coefficients of radial velocity within the frequency range 2.5–5 Hz. Note the different Y axis scales for the two cases. Mean visual ratings of the four raters for the two spirals were as follows: “impairment” (bradykinesia = 4.75, dyskinesia = 7), “speed” (2.25, 0), “irregularity” (2, 2.75), and “hesitation” (1.5, 0.25). The spirals had the following feature values: mean drawing speed (bradykinesia = 55.8, dyskinesia = 289), standard deviation of wavelet coefficients (14.8, 69.3), Approximate Entropy of drawing speed (0.06, 0.52), and total symmetry (0.18, 0.04).