TABLE 3.

Overall and subgroup analysis results regarding the effects of VRT on balance and functional mobility.

Outcomes	Overall and Subgroup analysis	Number of studies	WMD (95% CI)	P-value	Test of heterogeneity
					χ2	P-value	I2(%)
TUG	Overall	15	−0.31 (−0.57, −0.05)	0.02	15.17	0.37	7.72
	Immersion
	Yes	3	−0.52 (−0.95, 0.08)	0.02	0.47	0.79	0
	No	12	−0.26 (−0.61, 0.09)	0.14	13.08	0.29	15.92
	Frequency (times/week)
	<3	6	−0.38 (−0.85, 0.08)	0.11	9.81	0.08	49.02
	≥3	9	−0.25 (−0.73, 0.24)	0.32	5.34	0.72	0
	Length (weeks)
	<8	4	−0.03 (−0.38, 0.32)	0.89	1.24	0.74	0
	≥8	11	−0.45 (−0.77, −0.13)	0.01	10.54	0.39	5.17
	Weekly intervention time
	<120	9	−0.33 (−0.80, 0.14)	0.17	11.91	0.16	32.84
	≥120	6	−0.42 (−0.79, −0.05)	0.03	2.38	0.79	0
	Total intervention time (min)
	<800	9	−0.39 (−0.89, 0.10)	0.12	11.92	0.15	32.89
	≥800	6	−0.38 (−0.75, −0.01)	0.04	2.79	0.73	0
	Design principles
	Repetitive, varied practice of meaningful tasks	8	−0.33 (−0.80, 0.14)	0.17	9.64	0.21	27.39
	The task difficulty is progressively increased according to the user’s ability	4	−0.17 (−0.88, 0.55)	0.64	3.43	0.33	12.60
	Repetitive, varied practice of meaningful tasks + Sensory feedback that is related to the task is necessary	3	−0.52 (−0.95, 0.08)	0.02	0.47	0.79	0
OLS-O	Overall	6	7.28 (4.36, 10.20)	0.00	7.84	0.17	36.22
	Immersion
	Yes	2	6.41 (2.69, 10.12)	0.00	0.77	0.38	0
	No	4	7.48 (3.16, 11.79)	0.00	5.60	0.13	46.43
	Frequency (times/week)
	<3	2	6.74 (−7.13, 20.62)	0.34	1.84	0.18	45.55
	≥3	4	5.96 (3.10, 8.82)	0.00	0.92	0.82	0
	Length (weeks)
	<8	3	8.30 (4.59, 12.01)	0.00	4.08	0.13	51.00
	≥8	3	4.92 (0.52, 9.33)	0.03	0.85	0.65	0
	Weekly intervention time
	<120	3	1.25 (−0.53, 3.03)	0.17	18.59	0.00	89.24
	≥120	3	6.14 (2.76, 9.52)	0.00	0.88	0.64	0
	Total intervention time (min)
	<800	3	7.88 (2.62, 13.15)	0.00	4.47	0.11	55.31
	≥800	4	6.40 (2.81, 9.99)	0.00	1.30	0.52	0
	Design principles
	Repetitive, varied practice of meaningful tasks	2	9.10 (4.04, 14.15)	0.00	1.74	0.19	42.69
	The task difficulty is progressively increased according to the user’s ability	2	4.95 (−0.27, 10.17)	0.06	0.85	0.36	0
	Repetitive, varied practice of meaningful tasks + Sensory feedback that is related to the task is necessary	2	6.41 (2.69, 10.12)	0.00	0.77	0.38	0
FRT	Overall	6	−1.97 (−4.37, 0.42)	0.11	38.78	0.00	87.11
	Immersion
	Yes	2	−1.61 (−7.17, 3.94)	0.57	16.64	0.00	93.99
	No	4	−2.13 (−4.37, 0.42)	0.16	15.76	0.00	80.96
	Frequency (times/week)
	<3	4	−1.80 (−4.52, 0.92)	0.19	22.43	0.00	86.63
	≥3	2	−2.40 (−9.74, 4.94)	0.52	16.25	0.00	93.84
	Length (weeks)
	<8	2	0.33 (−0.91, 1.58)	0.60	0.31	0.36	0
	≥8	4	−3.65 (−5.86, −1.44)	0.00	9.69	0.00	69.05
	Weekly intervention time
	<120	3	0.46 (−1.63, 0.72)	0.45	1.17	0.56	0
	≥120	3	−3.08 (−6.89, 0.72)	0.11	20.39	0.00	90.19
	Total intervention time (min)
	<800	2	−0.50 (−1.80, 0.80)	0.45	1.16	0.34	13.66
	≥800	4	−2.73 (−6.22, 0.76)	0.13	21.14	0.00	85.81
	Design principles
	Repetitive, varied practice of meaningful tasks	3	−2.36 (−5.63, 0.91)	0.16	15.65	0.00	87.22
	The task difficulty is progressively increased according to the user’s ability	1	0.00 (−8.32, 8.32)	1.0	–	–	–
	Repetitive, varied practice of meaningful tasks + Sensory feedback that is related to the task is necessary	2	−1.61 (−7.17, 3.94)	0.57	16.64	0.00	93.99
GS	Overall	5	−0.02 (−0.08, 0.03)	0.44	6.63	0.16	39.65
	Immersion
	Yes	1	0.01 (−0.04, 0.06)	0.68	0	–	–
	No	4	−0.04 (−0.12, 0.03)	0.28	4.72	0.19	36.49
	Frequency (times/week)
	<3	2	0.05 (−0.16, 0.06)	0.36	2.03	0.15	50.72
	≥3	3	−0.01 (−0.08, 0.07)	0.84	3.44	0.18	41.89
	Length (weeks)
	<8	1	0.01 (−0.04, 0.06)	0.68	0	–	–
	≥8	4	−0.04 (−0.12, 0.03)	0.28	4.72	0.19	36.49
	Weekly intervention time
	<120	3	−0.02 (−0.12, 0.07)	0.64	3.65	0.16	45.18
	≥120	2	−0.03 (−0.13, 0.07)	0.57	2.70	0.10	62.94
	Total intervention time (min)
	<800	3	−0.02 (−0.12, 0.07)	0.64	3.65	0.16	45.18
	≥800	2	−0.03 (−0.13, 0.07)	0.57	2.70	0.10	62.94
	Design principles
	Repetitive, varied practice of meaningful tasks	3	−0.06 (−0.14, 0.01)	0.09	2.57	0.28	0
	The task difficulty is progressively increased according to the user’s ability	1	0.07 (−0.09, 0.23)	0.40	0	–	–
	Repetitive, varied practice of meaningful tasks + Sensory feedback that is related to the task is necessary	1	0.01 (−0.04, 0.06)	0.68	0	–	–

TUG, Timed Up and Go; OLS-O, one-leg stance with open eyes; FRT, functional reach test; GS, gait speed.