User-Centred Design and Usability Evaluation of a Heart Rate Variability Biofeedback Game

Reduced heart rate variability (HRV) is an indicator of a malfunctioning autonomic nervous system. Resonant frequency breathing is a potential non-invasive means of intervention for improving the balance of the autonomic nervous system and increasing HRV. However, such breathing exercises are regarded as boring and monotonous tasks. The use of gaming elements (gamification) or a full gaming experience is a well-recognised method for achieving higher motivation and engagement in various tasks. However, there is limited documented knowledge on how to design a game for breathing exercises. In particular, the influence of additional interactive elements on the main course of training has not yet been explored. In this paper, we evaluated the satisfaction levels achieved using different game elements and how disruptive they were to the main task, i.e., paced breathing training. An Android flight game was developed with three game modes that differ in the degrees of multitasking they require. Design, development, and evaluation were conducted using a user-centred approach, including context analysis, the design of game principle mock-ups, the selection of game principles through a survey, the design of the game mechanics and GUI mock-up, and icon testing, and the performance of a summative study through user questionnaires and interviews. A summative evaluation of the developed game was performed with 11 healthy participants (ages 40-67) in a controlled setting. The results confirm the potential of video games for motivating players to engage in HRV biofeedback training. The highest training performance on the first try was achieved through pure visualisation rather than in a multitasking mode. Players had higher motivation to play the more challenging game and were more interested in long-term engagement. A framework for gamified HRV biofeedback research is presented. It has been shown that multitasking has considerable influence on HRV biofeedback and should be used with an adaptive challenge level.