Table 4.

Characteristics of the VR protocol

VR type	Article	Description	Viewpoint	Duration
Stationary	[25]	A video camera recognized the movements and position of the patient in a green room. In a monitor, the patient can see an image of herself in the VE. The patient interacts with virtual objects with a glove	1PP-mirror	30 min
	[30]	A computerized VR ski game was presented in a computer monitor. The interaction was carried on by a cylinder-like object that was grasped by the subject	1PP	15 min
	[31]	Patients played three Nintendo Wii games on a TV screen. These games provided various types of exercises for the UL, including movements of the shoulder, elbow, wrist, hand, and fingers	Depends on the game	45 min
	[29]	Wearable data gloves with sensors, the patient was seated in a comfortable chair with armrests performing shoulder, elbow, and wrist exercises. A therapist chose the therapy according to the needs and abilities of the patient	3PP	30 min
	[28]	Patients were seated in a comfortable chair and wore 3D glasses in front of a stimulus presentation box, in which they would place their hands to grasp and lift a cup. The box hid the hands of the patient and displayed on screen the VR stimulus which consisted of VR hands aligned with the perception of patient hands	1PP	N/R
	[33]	The VE was presented in a laptop screen and showed both left and right virtual arms. The objective of the task was to pick up apples. For this, the patient had to attempt the reaching movement and look at the apple on the screen. The interaction was carried out with an eye-tracking device and armband capable of measuring EMG and position. Patient was seated in a comfortable chair	1PP	20 min
	[32]	The VE was presented in a large screen and consisted of a game in which the patient had to hit a target object with a virtual ball through the movement of a mechanical handle	N/R	20 min
	[26, 37, 38]	The patient (child) was instructed to stand in front of a large screen measuring 200 × 150 cm and played a Kinect-controlled Xbox game that consisted of aerobic exercise (walking and walking with obstacles) games	Depends on the game	20 min
	[39, 40]	A screen-mirror setup was used to induce a walking visual illusion in the patient. The mirror reflected the upper body of the subject, while the screen showed patient-matched legs walking in a treadmill machine The interaction was performed by the mirror part of the setup. Additionally, audio feedback was provided	1PP-mirror	15 min
	[41]	The patient was positioned barefoot in front of a projector on a balance board with which the patient interacts with the VE provided by different games in Nintendo Wii Fit	1PP-mirror and 3PP, depending on game	20 min
Head-based	[34, 35]	The participant underwent two VR experiences, a neutral and a spider VR scene. The interaction consisted of the head position tracking by the HMD	1PP	6 min
	[36]	The participant underwent VR driving scenarios with standardized presentation of 12 warzone events. The interaction consisted in head tracking by the HMD. Combat-related multisensory feedback (visual, auditory, olfactory, and haptic) was provided	1PP	24 min

N/R not reported