Investigating the Impact of Transcranial Direct Current Stimulation and Virtual Reality Training on Enhancing Visuospatial Perception Abilities

다국어 초록 (Multilingual Abstract)

Investigating the Impact of Transcranial Direct Current Stimulation and Virtual Reality Training on Enhancing Visuospatial Perception Abilities Fang He Physical Therapy Major Department of Public Health Science Graduate School, Dankook University Advisor: Professor Sang Seok Yeo Visuospatial perception (VSP) is important for daily life, and remains vulnerable to neurological impairment. Virtual reality (VR) training and transcranial direct current stimulation (tDCS) have individually shown promise in improving visuospatial ability performance by neuromodulation, but their relative effectiveness and potential synergistic effects remain unclear. This study aimed to systematically compare the individual and combined effects of VR and tDCS, as well as sham intervention on visuospatial ability performance and cortical activity using functional near-infrared spectroscopy (fNIRS). Forty right-handed healthy adults (17 males, 23 females; aged 20-35 years) were randomly assigned to the VR group, tDCS group, combination group or sham group. All groups received four 20-minute sessions on non-consecutive days. The VR group performed virtual maze navigation tasks. The tDCS groups received the stimulation over the left posterior parietal cortex (PPC; anode: P3, cathode: P4) at 1.5 mA. The combined group received simultaneous tDCS and VR training. The sham group received the VR null environment and sham tDCS stimulation. The visuospatial ability was assessed using the Benton Judgment of Line Orientation Test (BJLOT) and Rey-Osterrieth Complex Figure (ROCF) test. Cortical hemodynamic responses during BJLOT task performance were measured using fNIRS targeting the occipito-parieto-temporal regions. VR-maze intervention significantly improved BJLOT efficiency and ROCF immediate and delayed recall, accompanied by significant increased right SPL activation. The tDCS intervention improved ROCF and BJLOT performance with deactivation of the left SOG and right STG, and reduced task-state functional connectivity between the left AG and left MTG. The combined intervention improved behavioral performance, but did not produce a synergistic effect compared to VR alone, showing deactivation in left MTG without functional connectivity changes. In this study, all active interventions improved visuospatial performance, the VR intervention alone showing superior behavioral performance. Each intervention modulates the posterior parieto-temporo-occipital network through different neural mechanisms. The combined intervention did not produce additive or synergistic effects.
Key words: virtual reality, transcranial Direct Current Stimulation, visuospatial ability, brain activity

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Method 10
• 1. Participants 10
• 2. Measurements 11
• 2.1 Rey-Osterrieth Complex Figure Test (ROCF) 11
• 2.2 Benton Judgment of Line Orientation Test (BJLOT) 13
• 2.3 Transcranial Direct Current Stimulation (tDCS) 15
• 2.4 Virtual Reality (VR) 17
• 2.5 Cortical activity 19
• 3. Experimental procedure 21
• 4. Data Analysis 25
• 4.1 Brain Activation Analysis 25
• 4.2 Function connectivity Analysis 27
• 5. Statistical procedure 28
• Ⅲ. Results 29
• 1. Demographic data of participants 29
• 2. The impact of various interventions on performance during visuospatial tasks 31
• 3. Changes in visuospatial task performance before and after intervention 33
• 4. HbO activity before and after intervention 39
• 5. Comparison of HbO responses between pre- and post-intervention 42
• 6. Task-state functional connectivity before and after intervention 45
• 7. Comparison of task-state functional connectivity between pre- and post-
• intervention in all groups 51
• Ⅳ. Discussion 54
• 1. Effect of VR-maze intervention on visuospatial ability 54
• 2. Effect of tDCS intervention on visuospatial ability 56
• 3. The influence on the visuospatial performance in combination intervention 61
• V. Limitation 64
• VI. Conclusion 66
• Reference 67