Modulation of Physiological Responses and Activity Levels During Exergame Experiences

UPDATE (09/09/2016): This paper received the Best Paper Award at the VS-Games 2016 conference in Barcelona, Spain.

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Exergames are exercise-oriented games that offer opportunities to increase motivation for exercising and improving health benefits. However, Exergames need to be adaptive and provide accurate feedback for physiologically correct exercising, sustaining motivation and for better personalized experiences. To investigate the role of physiological computing in those aspects, we employed a repeated measures design exploring changes in physiological responses caused by the gaming and exercising components of an Exergame intervention. 

Videogame 

1) Design: the used videogame, called Exerpong, is an adaptation of the classic 2D Pong in which the player controls a virtual paddle to bounce a ball. Two different interaction modes are available: Exergaming and Control (with a conventional joystick). Exerpong was developed using the Unity 3D game engine (Unity Technologies, San Francisco, USA). The RehabNet Control Panel (Reh@Panel) software [36] is used to interface a depth sensor with Unity 3D. Through calibration, the user’s waist position is mapped to control a virtual paddle. Three different difficulty levels were implemented (easy, medium and hard) based on the modification of the velocity of the ball, size of the ball, and the size of the paddle. No scores were provided to avoid influencing long-term perception of success or failure. Game events were unequivocally labelled as missed balls or ball interceptions. Audiovisual stimuli (red and green visual feedback and positive and failure sounds) were used during gameplay to provide feedback on performance. 

2) Experimental Setup: a white PVC surface (2.5 m x 3.0 m) was used to project the Exerpong game on the floor in front of the participants (Figure 1). The projection had a resolution of 1280x720 pixels and the perspective was corrected to the surface using a mapping application. Figure 1. Diagram depicting the Exerpong setup consisting of a Kinect sensor, a projected environment and a wearable physiological kit. The user stands in front of the projection and controls a virtual paddle. We used the fighting stick EX2 for Xbox360 to enable the control of the virtual paddle with a joystick in the Control condition. Users sat in a chair in front of the floor perpendicular to the paddle-movement axis, and controlled the joystick using their right hand. A Kinect v1 sensor (Microsoft, Microsoft, Washington, USA) enabled the control of the virtual paddle through body motion in the Exergaming condition. EDA and ECG signals were recorded through a Bluetooth connection using the BioSignal Plux toolkit (Plux Wireless Biosignals, Lisboa, Portugal), a wearable bodysensing platform. EDA signal was recorded using two Ag/AgCl electrodes attached to the middle phalanges of the middle and index fingers of the participant’s left hand. ECG signals were recorded using a surface mount triode dry electrode with standard 2 cm spacing of silver chloride electrodes placed on the V2 pre-cordial derivation. Conductive gel to facilitate signal recording was used in some participants when necessary.

Seventeen older adults (64.5±6.4 years) interacted with a videogame in two modes (Control, Exergaming) in different difficulty levels. Electrocardiography, Electrodermal and Kinematic data were gathered synchronously with game data. Findings show that Exercise intensities and heart rate changes were largely modulated by game difficulty, and positive feedback was more likely to produce arousal responses during Exergaming than negative feedback. A heart rate-variability analysis revealed strong influences of the interaction mode showing that Exergaming has potential to enhance cardiac regulation. Our results bring new insights on the usefulness of psychophysiological methods to sustain exercising motivation and personalizing gameplay to the individual needs of users in Exergaming experiences. 

Reference:

J.E. Muñoz, M S Cameirão, ER Gouveia, T Paulino, S. Bermúdez i Badia. (2016). Modulation of Physiological Responses and Activity Levels During Exergame Experiences. Presented at the VS-Games 2016 - 8th International Conference on Virtual Worlds and Games for Serious Applications, Barcelona, Spain. (Download) (Cite)