Figure 4.

l‐Dopa mediates subject‐specific improvements in gait and balance in the NHP model of PD. (A) Recordings of whole‐body kinematics during locomotion along a runway. Gait patterns are recorded using a high‐speed motion capture system. They are subsequently reconstructed in 3‐D, discretized per gait cycle, decomposed into numerous gait parameters, and analyzed using PC analysis. All gait cycles for 4 monkeys (S1‐S4) are shown in the space defined by PC1 and PC2, which also includes the mean gait cycles of 6 healthy monkeys for comparison (each symbol is an average of 10 to 20 gait cycles; black square, healthy; white circle, MPTP no l‐dopa; blur circle, MPTP 50% l‐dopa; purple circle, MPTP 100% l‐dopa). Plus signs mark the mean position of gait cycles for each condition. Gait of monkeys S1 and S2 became more similar (closer) to the gait of healthy monkeys following 100% l‐dopa treatment. Monkey S3 exhibited severe dyskinesia following 100% l‐dopa treatment, which was captured in the large displacement of gait cycles in the PC1‐2 space. Following the same treatment, the gait of monkey S4 moved farther away from those of healthy monkeys, indicating deterioration of gait performance. (B) Representative stick diagram decomposition of hind‐limb movements (left column) and traces of key gait variables (right column) for 3 l‐dopa doses (0%, 50%, and 100%) followed by 1 hour of vehicle gas inhalation (50% N₂, 50% O₂). (C) Bar plots showing changes in the mean Euclidean distance between all gait cycles in a given condition and the average gait cycle of all healthy monkeys. The other bar plots report average values for key parameters of gait (speed and stance duration) and posture (hip position) for the 3 experimental conditions. Data reported as mean. Error bars ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001; Wilcoxon rank sum test. [Color figure can be viewed at http://wileyonlinelibrary.com]