A Comparative Study of Prism Adaptation Using Virtual Reality and Conventional Prism Glasses.

BACKGROUND

Unilateral spatial neglect (USN) is a symptom of cerebrovascular disorders characterized by impaired attention to the space opposite a cerebral hemisphere lesion. Prism adaptation (PA) is a rehabilitation technique considered effective for treating USN. PA involves performing tasks while wearing prism glasses, which shift the visual field and help correct spatial perception. However, methods tailored to the severity of USN have not been fully established. Virtual reality (VR) has been proposed as a potential solution. This study aimed to compare the effects of a VR-based PA system and conventional prism glasses under equivalent task conditions.

METHODS

The participants included 40 healthy, right-handed adults. Each participant completed three conditions: control, prism glasses, and VR. The order of these conditions was counterbalanced across participants. A one-week washout period was implemented between conditions. For evaluation, the open-loop pointing (OLP) test, the landmark task, and the line bisection task were administered as baseline assessments. Participants then performed the PA task. After the PA task, the same evaluations were repeated as post assessments. A leftward deviation following the PA was considered indicative of successful adaptation. A chi-square test was used to analyze changes in OLP test scores between the pre- and post assessments. Furthermore, for participants with successful PA, a one-way analysis of variance (ANOVA) was conducted to compare the magnitude of aftereffects across conditions.

RESULTS

Among the 40 participants, 19 showed a leftward deviation in the prism glasses condition and 34 in the VR condition, indicating a statistically significant difference. Among the 17 participants with successful PA in both the prism and VR conditions, a one-way ANOVA revealed a significant main effect in OLP test score changes. Post hoc analysis revealed significant differences between the control condition and both the prism glasses and VR conditions.

CONCLUSION

The VR-based PA system induced PA in more participants than conventional prism glasses and produced comparable aftereffects. These findings support the utility of VR-based PA and suggest its potential to advance future rehabilitation methods.