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.

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.