Table 1.

Basic eye-movement parameters by task.

	Eye-movement parameter		U-test
			Young (SD)	Old (SD)	Z-value	p-value	Effect-Size (AUC)
Task I (walking with free gaze)	median saccade amplitude [°]		4.14 (1.31)	3.25 (1.07)	1.894	0.058	0.692 [0.513 0.871]
	median saccade peak-velocity [°/s]		285.6 (51.4)	220.2 (24.2)	3.789	0.0002	0.882 [0.764 1.000]
	median saccade mean-velocity [°/s]		199.2 (29.1)	168.3 (17.8)	3.134	0.0017	0.817 [0.671 0.962]
	median q-value		1.40 (0.06)	1.31 (0.06)	3.479	0.0005	0.851 [0.719 0.984]
	main-sequence fit K-value		185.0 (24.7)	154.4 (22.8)	3.169	0.0015	0.820 [0.676 0.965]
	main-sequence fit L-value		0.335 (0.04)	0.359 (0.08)	−0.689	0.491	0.429 [0.235 0.624]
	mean saccade frequency [1/s]		3.03 (1.37)	1.83 (1.04)	2.582	0.010	0.761 [0.598 0.924]
	mean freeviewing-gain		1.31 (0.31)	1.56 (0.29)	−2.224	0.026	0.259 [0.077 0.441]
	mean blink rate [1/s]		0.474 (0.32)	0.801 (0.57)	−1.826	0.068	0.315 [0.135 0.495]
	median saccade peak-velocity [°/s] for certain saccade amplitudes	1°–2° (22.5%)	202.9 (35.1)	187.4 (37.1)	2.032	0.042	0.706 [0.530 0.882]
		2°–3° (11.5%)	244.3 (52.9)	207.9 (28.1)	2.342	0.019	0.737 [0.568 0.906]
		3°–5° (14.7%)	251.6 (28.8)	226.9 (18.6)	2.962	0.003	0.799 [0.648 0.951]
		5°–8° (14.6%)	317.0 (34.8)	283.0 (24.9)	2.997	0.003	0.803 [0.652 0.953]
		8°–15° (15.3%)	413.6 (37.0)	363.9 (41.5)	2.514	0.012	0.855 [0.722 0.988]
Task II (tracking targets)	mean tracking-gain tracking RMSE		0.957 (0.13)	0.865 (0.22)	1.264	0.206	0.643 [0.436 0.850]
			16.99 (6.97)	17.80 (4.90)	−0.680	0.497	0.417 [0.190 0.643]

Computed eye-movement parameters of the two tasks (Task I and II) and their corresponding statistics. The percentage behind each saccade amplitude window reflects the prevalence of a saccade of that particular amplitude. The distinct analysis of amplitude ranges of more than 15° could not be evaluated reliably, because some participants did not perform sufficient saccades within this domain.