Evaluating Difficulty Adjustments in a VR Exergame for Younger and Older Adults: Transferabilities and Differences

Virtual reality (VR) exergames have the potential to train cognitive and physical abilities. However, most of these spatial games are developed for younger users and do not consider older adults with different design requirements. Yet, to be entertaining and efficient, the difficulty of games has to match the needs of players with different abilities. In this paper, we explore the effects of individually calibrating a starting difficulty and adjusting it: i) exactly as calibrated before, ii) 50% more difficult, and iii) 50% less difficult. In a user study, we compare the effects of using these adjustments on reaction times and subjective measures on younger (n=30) and older adults (n=9). The results show that most of the users prefer a faster-paced VR game in terms of enjoyment, but this also resulted in a higher perceived workload. Compared to the younger adults, the older adults rated the game more positive in terms of higher enjoyment and eagerness to play the game again, as well as lower perceived workload. This emphasizes the need for games to be designed for the user group they are intended for; both in terms of cognitive-physical difficulty and game content. Furthermore, we reflect on the transferability of the results obtained from testing with the younger adults and highlight their potential, especially for identifying suggestions and issues with the gameplay.