## 2 Related Works
### AR and VR Technologies to Promote Wellbeing of Older Adults  
Various studies have been conducted on healthy aging for the purpose of increasing the average healthy life of older adults. However, in reality, studies on diverse technological interventions are still insufficient to optimize their physical, psychological, and social wellbeing [32]. The studies on emerging technologies for them mainly focus on supporting mental or physical health and wellbeing in later life. [PERSON] et al. [32] indicated that it is important to balance physical, psychological, and social wellbeing to promote active and happy aging. VR and AR are emerging technologies that are increasingly integrated into our everyday lives, from entertainment to healthcare. Even though VR and AR have huge potential as technology-based interventions to promote and maintain overall wellbeing of older adults' life, studies related to this group have not conducted actively. VR allows older adults to be fully immersed in the virtual environment, isolated from real-world circumstances, by using devices such as haptic controllers [33; 34]. AR provides virtual experiences to users, by keeping the real world in the center and layering digital information. An advantage of VR and AR is enabling users to have tremendous experiences of a new world; thus, older adults have an immersive experience of some places, which they could not otherwise visit because of their physical impairment and reduced mobility, without having to spend time and energy. VR gives a full, detailed view of a place, which makes it more interesting and engaging to older adults. Another advantage of VR and AR is to allow them to receive risk-free training. That is, they provide new, safer ways to simulate practices for cognitive and physical training for older adults, without exposing them to hazardous environments. One disadvantage is that overuse of VR and AR lead to older adults having difficulty in distinguishing between real and virtual worlds. The most difficult challenge to them in using VR is to implement the system, and thus, they need one-on-one assistance to use such technologies. Above all, VR and AR allow communicating and building relationships with others in the virtual world. However, communication using VR or AR should not replace human interaction. Some older adults might have concerns that using these technologies can take away an important aspect of social interaction in real life. Despite such advantages and disadvantages, it is difficult to dispute the fact that VR and AR are interesting enough to attract attention from older adults. Since VR and AR technologies can be an intervention for improving their wellbeing [35], such applications are increasingly employed in the healthcare domain for assessment, training, and rehabilitation of older adults with different disorders. Many studies have indicated that VR and AR applications have good potential of improving the treatment of health-related issues and the quality of life significantly. Most of all, VR and AR offer many opportunities to have enjoyable experiences. Physical and cognitive training can be boring, tiring, and unmotivating for older adults, and thus, several interactive games using VR and AR are developed to motivate them to use these [36]. Since VR interactive games have a fun factor, such games are used as a complementary tool in rehabilitation to enrich older adults' practical activities. In addition, AR and VR will be new platforms for new types of social interaction [37]. They provide some opportunities for various social interactions to older adults, who have been reluctant to engage in such interactions owing to their physical disabilities. VR has been utilized to enhance the ability to perform activities of daily living, such as taking medications, preparing meals, remembering tasks to do, and using navigational skills in ambulation and driving [38]. VR and AR applications are widely used to make their life better and convenient.