This project will explore the feasibility and efficacy of the fully immersive virtual reality leisure cognitive training tool developed by Chang Gung University in patients with mild to moderate dementia. The feasibility study will assess the feasibility and emotion-related indicators of 10 patients before and after a single training session. The efficacy study is planned to adopt a crossover randomized controlled trial, recruiting 30 patients for 15 sessions, each lasting 65 minutes, conducted three times a week. The assessment will include tests on the primary variable of cognitive function and secondary variables such as activities of daily living, quality of life, emotion, clinical symptoms, etc.