Table 2. The assessment of concurrent validity between two gait measurement instruments and an analysis of error.

The results of inter-instruments agreement and error of measurement in group of healthy adults (HA) and patients with Parkinson’s disease (PD). Paired t-test p-value, intraclass correlation coefficient (ICC) and Passing-Bablok (PB) slope, intercept and residuals mean are reported.

	Paired t-test: p-value		ICC(2,k): rho (95% CI)		PB: slope (95% CI)		PB: intercept (95% CI)		PB: residuals mean (1.96 RSD)		PB: MSE
Gait variable	HA	PD	HA	PD	HA	PD	HA	PD	HA	PD	HA	PD
Cadence (steps/min)	0.636	0.871	0.99 (0.97,0.99)	0.98 (0.96,0.99)	0.97 (0.92,1.03)	0.97 (0.90,1.04)	2.98 (−2.69,9.59)	2.41 (−4.32,11.21)	0.08 (±4.34)	0.53 (±7.75)	4.78	15.28
Speed (m/s)	0.103	0.049	0.87 (0.76,0.93)	0.98 (0.94,0.99)	1.02 (0.81,1.31)	0.86 (0.77,0.94)	−0.06 (−0.43,0.21)	0.11 (0.03,0.20)	−0.01 (±0.29)	<0.01 (±0.13)	0.02	<0.01
Stride duration (s)	0.134	0.689	0.98 (0.97,0.99)	0.81 (0.56,0.92)	0.99 (0.92,1.05)	1.00 (0.94,1.06)	0.02 (−0.05,0.09)	0.01 (−0.06,0.07)	<0.01 (±0.05)	−0.02 (±0.36)	<0.01	0.03
Stride length (m)	0.113	0.191	0.82 (0.67,0.91)	0.95 (0.89,0.98)	1.50 (1.17,2.10)	0.80 (0.67,0.92)	−0.76 (−1.63,−0.28)	0.21 (0.05,0.36)	−0.02 (±0.30)	<0.01 (±0.16)	0.02	0.01
Stance (%)	<0.001	<0.001	0.22 (−0.30,0.58)	0.12 (−0.22,0.48)	1.49 (0.78,2.57)	0.36 (0.11,0.67)	−35.18 (−104.29,10.58)	35.89 (15.57,51.75)	0.68 (±5.74)	−0.45 (±4.20)	8.82	4.61
Swing (%)	<0.001	<0.001	0.22 (−0.30,0.58)	0.12 (−0.22,0.48)	1.52 (0.78,2.59)	0.36 (0.11,0.67)	−15.03 (−52.60,11.41)	28.17 (17.44,36.98)	−0.71 (±5.81)	−0.46 (±4.19)	9.09	4.60
Double support (%)	<0.001	<0.001	0.24 (−0.31,0.61)	0.10 (−0.22,0.45)	1.48 (0.86,2.60)	0.26 (0.03,0.60)	−20.97 (−52.90,−3.29)	10.76 (−0.24,17.83)	1.71 (±11.78)	−0.59 (±8.27)	38.12	17.40
Single support (%)	<0.001	<0.001	0.22 (−0.29,0.59)	0.13 (−0.24,0.50)	1.74 (0.94,3.28)	0.27 (0.01,0.71)	−22.96 (−78.50,5.60)	31.44 (16.16,40.27)	−0.63 (±6.38)	0.10 (±4.33)	10.72	4.69