Figure 3.

Oculomotor spatio-temporal properties in MS and PD cohorts, compared to an age-matched normative baseline. For the spatio-temporal analysis of the continuous gaze tracking task, we applied the eye-movement crosscorrelogram method (13, 14). From all features computed, we selected the two temporal and two spatial features that were shown to be most strongly modulated by stimulus velocity (30). The selected features are: “lag” (F1), “temporal uncertainty” (F2), “error spread” (F3), and “dissimilarity” (F4). “Lag” represents the delay between eyes and stimulus, measured as the temporal offset of the peak of the cross-correlation between stimulus and eye velocities. “Temporal uncertainty” represents the consistency of the velocity of the eye in relation to the velocity of the stimulus. “Error spread” is the standard deviation of the distribution of eye-stimulus positional deviations. “Dissimilarity” is the inverse of the cosine similarity computed between the arrays of gaze coordinates and stimulus coordinates.