Figure 1.
Velocity probability distributions of Parkinson's patients are shifted toward slower movements in all but the easiest conditions. Probability distribution functions for each condition were estimated using kernel density estimation based on all movements (valid and invalid) (see Mazzoni et al., 2007), and normalized [for non-normalized histograms, see Mazzoni et al. (2007), their Fig. 7 (http://www.jneurosci.org/cgi/content/full/27/27/7105/F7)]. In red are the estimated distributions for PD patients, in black are those for healthy controls. Shaded areas mark the required range of velocities in each condition [slow (S), 17–37 cm/s; medium (M), 37–57 cm/s; fast (F), 57–77 cm/s; very fast (VF), 77–97 cm/s], and numbers in bold (6,12, or 16) denote the distance to target in centimeters. Dashed line, Empirical mean. Data are courtesy of Dr. Pietro Mazzoni (Mazzoni et al., 2007)