Table 2.

Data extraction of the included studies.

Study	Age	Gender	Sample size	Experimental group	Control group	Hoehn-Yahr scale	Dosage	Outcome measures	Conclusion
Pompeu et al 2012	Mean 67.4	M/F: 17/15	32	Wii based training	Traditional training (Balance Exercises)	1–2	I hour/Day, 2 days/week, Total 7 wks	BBS,UPDRS, MCA	The Wii based training and traditional training exercises do not have a significant difference in improving balance in patients with PD
Shih et al 2016	EG: Mean: 67.5 CG: Mean 68.8	M/F: 16/4	20	Balance-based exergaming game	Conventional balance training	1–3	2 sessions every week, for 8 wks	LOS, OLS, BBS, TUG	Compared to conventional training, exergaming creates significant improvements in postural stability.
Yang et al 2015	EG: Mean:72.5 CG: Mean:75.4	M/F:14/9	23	Customized VR balance training system	Static posture stability and weight shifting in dynamic posture	3	50 minutes/ session (6 wks in total)	UPDRS-III, BBS, TUG test	VR based balance training was equally effective as training carried out in home environment for improvising balance function, ability to walk, and quality of life.
van den Heuvel et al 2014	EG: mean:66.3 CG: Mean: 68.8	M/F: 20/13	33	VFT	Conventional training	02–03	Ten group treatment session of 60 min duration, for 5 wks	FRT, SLS, 10 MWT, UPDRS, BBS, TUG test	VFT appeared to be practicable and harmless approach. However, no significant difference was found in any outcome measure.
Shen et al 2014	EG:Mean 63.3 CG: Mean 65.3	M/F: 25/20	45	balance and gait training with VFT	lower-limb strength training	2.5	Training for 12 wks	ABC scale,LoS, SLS, and spatiotemporal gait characteristics	Positive effects of augmented feedback training. P0 <0 0.05 in ABC score, Gait velocity, stride length
Santos et al (2019)	NW group: mean 61.7CE group: mean: 64.5NW+CE:mean: 66.6	M	45	Nintendo Wii(NW) game	2 control groups1. Nintendo wii + conventional training2. conventional training group	01–03	50 min, twice a week	BBS, DGI, TUG, PDQ-39	In rehabilitating PD patients, the Nintendo Wii plus conventional exercises was statistically as effective as any intervention alone; however, the combination was more effective.
Robles et al 2016	EG: mean 68.75 CG: mean 64.2	M/F: 12/3	15	Full-amplitude repetitive finger-tapping (FT)	VR captured patients’ self-movements		4-wks of training	Finger-tapping test, Cortico-spinal excitability	The intervention group exhibited greater movement amplitude after treatment, therefore, indicating that VR can assist in improving motor function within the context of movement imitation therapy.
Pazzaglia et al 2019	Age (years)0 =0 CG: 70 EG:72	M/F: 35/16	51	VR training for consecutive 6 weeks with 400 min session 3 Times/week	Conventional rehab program for consecutive 6 weeks with 400 min session 3 Times/week		40-min session three times per week	BBS, DGI, DASH, Short SF-36	A VR protocol was superior to a conventional rehabilitation program for improving balance.
Melo et al 2018	Control: 65.580 ±0 13.04, Treadmill group: 610 ±0 10.72, VR group: 60.250 ±0 9.28	M/F: 28/9	37	treadmill group, VR group	Conventional training group	01–03	20-min training sessions three times a week for 4 wks	6MWT, Inertial Measurement Unit (IMU)	Patients with PD in both groups did not experience any difference in treatment outcomes.
Ma et al 2011	EG: mean 64.77 CG: mean 68.13	M/F: 18/15	33	VR training	Placebo Training	02-03	60 trials	Movement time, peak velocity and percentage of movement time for acceleration phase	A brief VR training program improved the speed of movement of discrete target tasks while reaching for real moving objects, but therapy had a minimal effect on performance.
Liao et al 2015	CG:64.60 ±0 8.6 TE:65.10 ±0 6.7 VRWii:67.30 ±0 7.1	M/F: 17/19	36	VRWII group Traditional exercises group	Education group	01–03r	2 sessions per week over a 6-wk period	Level walking performance, FGA, Hand held dynamometer	VRWii is an exercise program that has shown effectiveness for patients with PD in improving their ability to walk and muscular strength..
Liao et al 2014	CG:64.60 ±0 8.6 TE:65.10 ±0 6.7 VRWii:67.30 ±0 7.1	M/F: 17/19	36	VR WII group Traditional exercises group	Education group	‘1–3	2 sessions per week) over a 6-wk period	LOS,PDQ-9), (FES-), and (TUG)	Compared to traditional exercises, VR Wii training significantly increased dynamic balance in patients with PD, which assisted the use of VR Wii to improve balance.
Gandolfi et al 2017	Tele wii group:67.45control group:69.84	M/F:51/25	76	Home based Nintendo Wii fit training	Clinical based exercises targeting postural stability of the patients	2.5–3	Total of 21 sessions, 50 min duration/session, 7 successive weeks	BBS,ABC10-MWT, DGI	VR training at home significantly improved balance and postural instability compared to clinic based balance exercises in patients with PD.
Ferraz et al 2018	60 years of age	M/F: 37/25	62	Functional training groupBicycle exercise group	Kinect adventure group	2–3	three 50-min sessions per week for 8 wks	6MWT, 10MWT,SRT,PDQ-39	This study found that exergaming can improve the ability to walk in older people with PD. However, they have the same effect compared to bicycle training and functional training.
Hao Feng et al 2019	EG:67.47CG:66.93	M/F:17/13	28	VR training	conventional physical therapy	2.5–04	45 each session, 5 days/week, total duration 12 wks	BBS, TUGT, UPDRS-III, and FGA	The study results depicted that balance and gait were improved significantly in VR training group.
Cikajlo et al 2019	2D group: 71.30 ±0 8.4, 3D group: 67.60 ±0 7.6 years old	M/F	20	3D Oculus Rift CV1, Pick and place task in virtually created environment	Pick and place task in virtual environment	02–03	10-session 3 wks	Leap motion controller, (BBT), and IMI	3D immersive VR technology enhances the interest / pleasure worth resulting in robust and efficient physical functioning, and is a superior enhancement over 2D technology.
Yuan et al 2020	EG: mean 67.8, CG: mean 66.5	M/F: 11/13	24	Interactive video-game–based exercise (IVGB)	No interactive video-game–based Exercise in control phase	01–03	6–12 wks	BBS, SF-36, MFES, MSL	IVGB exercise training can improvise physical function as an alternate therapy regime among mild to moderate presentation of PD.
Su et al 2014	EG: 64.76 CG: 64.71	M/F:26/16	42	projection-based VR system and balance board	projection-based VR system and balance board	02–03	15 test trials for each difficulty level of selected game, with a 5-min break	Wii balance board kinematic variables such as peak velocity, end of movement	Varying the speed of moving objects in VR system has an impact on speed of arm and COP among PD patients
Barros et al 2014	45–85 y old	M/F	15	Virtual exercises such as aerobic and balance exercises		02–04	14 session in total, twice per week (each session lasting for 40 min)	(UPDRS III), SE-ALD, FIM, and biomechanical analysis of gait	Nintendo Wii Fit Plus platform training was effective and efficient in a short time period for improving gait.
Mirelman et al 2014	Mean: 67.1	M/F: 14/6	20	VR and treadmill training	VR without treadmill training	02–03	6 wks (three sessions per wk)	Accelerometer, UPDRS- III, (PDQ-39), MCA	Treadmill training + VR significantly improve physical performance and gait.
Ilaria Carpinella et al 2016	Average 70 y	M/F	42	Game pad system	Structured physiotherapy without feedback	02–04	20 sessions of 45 min each, 3 times a wk	BBS, 10 meter walk test, Tele-healthcare Satisfaction questionnaire	Statistically significant between-group differences in BBS p0 =0 0.047
Moon et al 2020	EG: mean 63.38, CG: mean 62.14	M/F: 10/5	15	balance training using Wii Fit (BTWF)+ traditional occupational therapy	traditional occupational therapy	02–03	3 times/ week, in total for 8 weeks and 30 minutes of Wii fit training in each single session	BBS, TUG, MBI	The Wii Fit training resulted in significant changes in BBS score in comparison to the control group.
Lee et al 2015	EG: mean 68.4, CG: mean 70.1	M/F: 10/10	20	VR dance exercise plus neurodevelopment training plus functional electrical stimulation	neurodevelopment training plus functional electrical stimulation		6 wks	BBS, the MBI Index, and the BDI	VR dance exercises have a positive effect on balance, the ADLs and the depression status of Parkinson’s patients with P value0 <0 0.05.
Tollar et al 2018	EXE:70.00 ±0 4.69 CYC:70.60 ±0 4.10 CON: 67.50 ±0 4.28	M/F36/38	74	Exergaming	Stationary cycling (CYC) andWaitlist	2–3	60 min/d 5 d/w5 w	PDQ-39BBS	VR group improved significantly in BBS scores in comparison to the control group.
Ribas et al 2017	610 ±0 9.11	M/F8/12	20	ExergamingWii fit games	Conventional exercise	1–3	30 m/d2 d/w12 wks	BBSPDQ-39	Short-term, significant improvements in BBS.