Effects of a Stimulus Response Task Using Virtual Reality on Unilateral Spatial Neglect: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effects of a stimulus response task using virtual reality (VR) for unilateral spatial neglect (USN). DESIGN: Double-blind randomized controlled trial. SETTING: Acute phase hospital where stroke patients are hospitalized. PARTICIPANTS: The participants were 42 patients (N=42) with right-hemisphere cerebral damage who had been experiencing USN in their daily lives. They were randomly assigned to 3 groups: a stimulus response task with a background shift (SR+BS group), a stimulus response task without a background shift (SR group), and an object gazing task (control group). INTERVENTIONS: The stimulus response task was to search for balloons that suddenly appeared on the VR screen. A background shift was added to highlight the search in the neglected space. The control task was to maintain a controlled gaze on a balloon that appeared on the VR screen. The intervention period was 5 days. MAIN OUTCOME MEASURES: The primary outcome was the participants' scores on a stimulus-driven attention test (SAT) using the reaction time. The stimuli of the SAT were divided into 6 blocks of 3 lines on each side (-3 to +3). The secondary outcomes were their scores on the Behavioral Intention Test conventional, Catherine Bergego Scale, and straight ahead pointing tests. RESULTS: In the SAT, there were significant interaction effects of reaction time between time and group factors in left-2, right+2, and right+3. The SR+BS and SR groups showed significant improvements in the reaction time of left-2 and right+3 compared with the control group. Moreover, the SR+BS group showed a significant improvement in the reaction time of left-2, which was the neglected space, compared with the SR group. However, there were no significant interaction effects of Behavioral Intention Test conventional, Catherine Bergego Scale, and straight ahead pointing. CONCLUSIONS: Our results suggest that the use of stimulus response tasks using VR combined with background shifts may improve left-sided USN.

Immediate Effect of an Intervention Using a Head-mounted Display with a Modified Pitch Angle on Spatial Awareness and Standing Balance in Stroke Hemiparesis.

Objectives: This study aimed to clarify the effect of an intervention using a head-mounted display with a web camera set at a modified pitch angle on spatial awareness, sit-to-stand movement, and standing balance in patients with left and right hemisphere damage. Methods: The participants were 12 patients with right hemisphere damage and 12 patients with left hemisphere damage. The line bisection test, a sit-to-stand movement, and balance assessment were performed before and after the intervention. The intervention task involved pointing at targets 48 times in an upward bias condition. Results: Significant upward deviation on the line bisection test was noted in patients with right hemisphere damage. The load on the forefoot during the sit-to-stand movement was significantly increased. The range of anterior-posterior sway during forward movement in the balance assessment was reduced. Conclusions: An adaptation task performed in an upward bias condition may produce an immediate effect on upward localization, sit-to-stand movement, and balance performance in patients with right hemisphere stroke.

Immediate effects of head-mounted display adaptation in cases of unilateral spatial neglect: study of straight-ahead pointing.

[Purpose] This study aimed to clarify the effect of an adaptation of a deviation of the visual field in three axes on spatial cognition in patients with unilateral spatial neglect and distorted spatial perception in three dimensions. [Participants and Methods] Fifteen patients with cerebrovascular disease and symptoms of unilateral spatial neglect were included. Forty-eight pointing movements with a camera attached to a head-mounted display changed in three axes were compared with the control condition in which the camera was deflected only in the horizontal plane as with the prism adaptation. The main outcome measures were subjective straight-ahead pointing, line bisection, line cancellation, and star cancellation. [Results] The head-mounted display adaptive therapy was performed under conditions that varied in all three axes. The results indicated that it was possible to deflect the subjective straight-ahead pointing position to the lower left direction. [Conclusion] In contrast to the prism adaptation, which deflects the visual field in a single axis in the horizontal plane, the tri-axial adaptation corrected the median cognition in the left-right direction as well as the cognition of the body center, including the vertical direction.

Examination and treatment of unilateral spatial neglect using virtual reality in three-dimensional space.

Here, we developed a method that randomly generates balloons in the left-right, up-down, and near-far spaces on a monitor using a head-mounted display. In this study, we evaluated a lack of stimulus-driven attention case that was undetected by conventional assessments such as the Behavioral Inattention Test. We could identify mild neglect with our virtual reality method, as later confirmed using the Catherine Bergego scale. After repeated practice under a tilted background space condition, the patient demonstrated a reduction in the time needed to perceive the appearing balloons, suggesting a therapeutic effect.

Leftward Optical Shift Induces Bias in Line Bisection: A Study with Healthy Subjects Using a Head-mounted Display.

OBJECTIVE: The purpose of this study was to verify the effect on spatial perception in healthy young subjects of an unconscious leftward optical shift created by a head-mounted display (HMD) with an offset camera. METHODS: We recruited 40 healthy right-handed adults who were divided into four groups according to the hand used in the tests and the visual direction displayed by the HMD (centered or 10° left). Each of the four groups (n = 10) undertook line bisection tasks across four combinations of variables: using a finger/stick or a mouse to point at a touch panel located 60 or 120 cm away from the subject. RESULTS: According to the results, regardless of the hand used, when the index finger or a stick was used (reaching condition), the line bisection point was displaced significantly to the left of the center. Additionally, a major left-displacement trend was observed in the short-distance reaching task, which did not require the use of a stick. In contrast, the long-distance task required a stick to be used, and the left displacements were all smaller than those for the short-distance tasks that used the index finger. CONCLUSION: This finding may be explained by the subjects having sufficient experience coordinating hand and eye movements in the condition where they used their dominant hand and reached with their own arms without using a stick.