VIRGIL is a monocentric interventional study aiming to investigate the effect of immersion in a virtual tilted room on modulation of the verticality representation (postural vertical \[PV\] and visual vertical \[VV\]), which in turn might affect body orientation (head and trunk). To this end, the investigators will conduct a within-person randomized trial including post-stroke patients and healthy participants.
This project proposes to test the effect of immersion in a tilted virtual reality on verticality representation in hemisphere stroke patients showing lateropulsion and in healthy participants. The idea is to use the virtual reality as a tool to recalibrate the internal reference of verticality (contralesionally biased) in stroke patients and to experimentally create a bias in verticality perception of healthy participants, then to investigate how this modulation of the internal model of verticality might affect the erect posture. The investigators hypothesize that, in stroke patients, the recalibration of the verticality perception might ameliorate their lateropulsion, whereas in healthy participants, the experimental verticality bias introduced might induce a transient experimental lateropulsion. A transmodal modulation of the verticality perception, both on PV and VV, would imply a modulation by the virtual reality not only at the level of perception but also at the internal model of verticality, advocating for a powerful effect of this technology. The analysis of a post-effect (on verticality perception) that would continue after the intervention (immersion in the virtual titled room) would be a supplementary argument advocating for its clinical use in rehabilitation of post-stroke lateropulsion. To judge the effect of the immersion in tilted virtual reality, the following measures will be considered: (a) PV perception, (b) VV perception, (c) body orientation measured by inertial captors, and (d) weight-bearing asymmetry in erect posture assessed by posturography.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
40
The immersion in virtual reality will be based on the HTC VIVE® device and the software developed by the Virtualis Society.
University Hospital Grenoble
Grenoble, France
RECRUITINGChanges in the postural perception of the vertical (PV) before and during the immersion in a virtual tilted room, in stroke and healthy participants.
PV consists of testing the whole body orientation in sitting, perceived as vertical by participants, in complete darkness. PV will be tested by a well-validated apparatus and paradigm (Pérennou et al Brain 2008). PV orientation will be the average orientation (in degree) of the 10 trials performed for each condition.
Time frame: Days 1 and 3 if assignment to plane A or days 2 and 4 if assignment to plane B of the W2
Changes in the visual perception of the vertical (VV) before and during the immersion in a virtual tilted room, in stroke and healthy participants.
VV consists of testing the direction of a visual line, perceived as vertical by particpants, in complete darkness. VV will be tested by a well-validated apparatus and paradigm (Pérennou et al Brain 2008 ; Piscicelli \& Pérennou 2017). VV orientation will be the average orientation (in degree) of the 10 trials performed for each condition.
Time frame: Days 1 and 3 if assignment to plane A or days 2 and 4 if assignment to plane B of the W2
Post-effect on PV. Change from baseline in PV orientation that continues after the immersion in virtual reality, in stroke and healthy participants.
Persistence of PV improvement in stroke participants and persistence of PV change in healthy participants, for at least 20 minutes after the virtual reality is stopped until a maximum of 1 hour.
Time frame: Days 1 and 3 if assignment to plane A or days 2 and 4 if assignment to plane B of the W2
Post-effect on VV. Change from baseline in VV orientation that continues after the immersion in virtual reality, in stroke and healthy participants.
Persistence of VV improvement in stroke participants and persistence VV change in healthy participants, for at least 20 minutes after the virtual reality is stopped until a maximum of 1 hour.
Time frame: Days 1 and 3 if assignment to plane A or days 2 and 4 if assignment to plane B of the W2
Modulation of active vertical trunk orientation. Change from baseline in active vertical trunk orientation assessed by inertial captors during the modulation of the internal model of verticality by virtual reality, in stroke and healthy participants.
Comparison between active vertical trunk orientation assessed by inertial captors at baseline and active vertical trunk orientation during the virtual reality immersion.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Modulation of active vertical pelvis orientation. Change from baseline in active vertical trunk orientation assessed by inertial captors during the modulation of the internal model of verticality by virtual reality, in stroke and healthy participants.
Comparison between active vertical pelvis orientation assessed by inertial captors at baseline and active vertical pelvis orientation during the virtual reality immersion.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Modulation of active vertical head orientation. Change from baseline in active vertical head orientation assessed by inertial captors during the modulation of the internal model of verticality by virtual reality, in stroke and healthy participants.
Comparison between active vertical head orientation assessed by inertial captors at baseline and active vertical head orientation during the virtual reality immersion.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Effect on lateropulsion. Change from baseline in lateropulsion scores assessed by the SCAle for LAteropulsion after 4 consecutive half days of verticality referential recalibration by virtual reality, in stroke participants.
Comparison of lateropulsion scores assessed by the SCAle for LAteropulsion (SCALA-scale, score from 0 (no lateropulsion) to 50 (severe lateropulsion with pushing); higher scores mean a worse outcome) at the end of each week (Fridays).
Time frame: 45 minutes every Friday during the protocol (W0, W1, W2, W3).
Effect on postural capacities. Change from baseline in balance scores assessed by the modified Postural Assessment Scale for Stroke patient after 4 consecutive half days of verticality referential recalibration by virtual reality, in stroke participants
Comparison of balance scores assessed by the modified Postural Assessment Scale for Stroke patient (m-PASS, score from 0 (major postural disorders) to 36 (no postural disorder), higher scores mean a worse outcome) at the end of each week (Fridays).
Time frame: 45 minutes every Friday during the protocol (W0, W1, W2, W3).
Responders to virtual reality. Proportion of participants in whom the immersion in a virtual tilted room modulates PV (at least 2 degrees).
Number of participants, stroke and healthy, in whom a change from baseline ≥ 2 degrees in PV orientation was observed during immersion in a virtual tilted room. The investigators hypothesize that the majority of participants (stroke and healthy) will be responders
Time frame: Days 1 and 3 if assignment to plane A or days 2 and 4 if assignment to plane B of the W2
Changes in weight-bearing asymmetry. Evaluation of changes in weight-bearing asymmetry in standing posture before and during the immersion in a virtual tilted room, in stroke and healthy participants.
Weight-bearing asymmetry assessed by posturography at baseline and during virtual reality, in patients and healthy participants. Comparison of both conditions.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Awareness of the changes in active vertical body orientation. Evaluation of participants' awareness of the changes in body orientation and balance in standing posture induced by virtual reality.
Perception of the body orientation change under virtual reality assessed by a 5-point Likert scale (ad-hoc scale, score from -2 \[perception of a higher lateropulsion\] to + 2 \[perception of a less severe lateropulsion\])
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Relationship between the trunk tilt (assessed by inertial captors, in degrees) and the weight bearing on the paretic side (in percentage of body weight), at baseline, with average values (2 sessions)
Active vertical body orientation measures and weight-bearing asymetry before virtual reality.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Relationship between the trunk tilt (assessed by inertial captors, in degrees) and the weight bearing on the paretic side (in percentage of body weight), during the virtual reality, with average values (2 sessions).
Active vertical body orientation measures and weight-bearing asymetry during virtual reality.
Time frame: Days 2 and 4 if assignment to plane A or days 1 and 3 if assignment to plane B of the W2
Quantification of a possible Virtual reality sickness.
Systematic evaluation of virtual reality sickness with a visual analogical scale (ad-hoc scale, from 0 to 10, higher scores mean a worse outcome).
Time frame: Days 1, 2, 3 and 4 of the W2
Description of symptoms in case of Virtual reality sickness.
Systematic evaluation of virtual reality sickness with a structured interview.
Time frame: Days 1, 2, 3 and 4 of the W2
Influence of verbal instruction on standing posture
Active vertical body orientation measures under three verbal conditions: : i) stand comfortably; ii) stand vertical and then iii) stand well symmetrical by distributing the weight equally between the two lower limbs.
Time frame: Days 1, 2, 3 and 4 of the W2
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