# eJamar: A Novel Exergame Controller for Upper Limb Motor Rehabilitation
###### Abstract  
This work presents the design of a new game controller device and the development of two exergames (Peter Jumper and Andromeda) for upper limb rehabilitation. The eJamar controller is a novel electromechanical device designed to measure wrist and hand movements, such as pronation/supination, flexion/extension, and ulnar/radial deviation, enabling users to perform control actions in the exergames. One of eJamar's most significant features is its ability to measure hand grip strength, a function not available in commercial gaming controllers. The exergame Peter Jumper involves a character jumping over obstacles in various environments, promoting hand grip exercises. The exergame Andromeda involves shooting enemy ships, promoting coordination between hand movements and grip strength, making it suitable for different rehabilitation techniques. A testing protocol was applied with eight healthy participants (5F and 3M), who completed a survey evaluating gameplay, usability, and satisfaction of the system. The results demonstrated that the developed exergames are intuitive and easy to play, with participants reporting that a therapist's presence is not required for gameplay. Hence, it suggests that the developed system can improve the rehabilitation process, promoting wrist-arm movements and grasping actions.  
are primarily accessible within rehabilitation centers, posing challenges for individual patient acquisition.  
Furthermore, there exist prototype systems tailored to address unique needs, encompassing aspects such as comfort, utility, operability, movement, and affordability. In this domain, devices have emerged to control gaming interfaces, such as the Bright Brainer Grasp [29], a therapeutic controller adept at sensing hand grasp and various hand movements crucial for rehabilitation. Another innovation includes a motion-tracking device [30] capable of monitoring hand movements, albeit without measuring grasp force. Additionally, the Arm Assist, functioning as a robotic system and game controller (GC), facilitates rehabilitation via hand movements [31]. Moreover, the Smart Elbow Bracelet, a two-degrees-of-freedom exoskeleton system, has been devised explicitly for rehabilitation in conjunction with exergames [32].  
In this context, this article describes the development of a novel therapeutic controller engineered according to specialized video game guidelines specifically for upper extremity rehabilitation denoted as ejamar. This device stands out by accurately measuring hand grasp, pronation-supination, flexion-extension, and ulnar-radial deviation movements of the hand. These distinct capabilities endow it with exceptional versatility for administering rehabilitation therapies effectively. The specialized ejamar technology aims to cover two purposes: (1) a rehabilitation tool serving as a GC to promote UL motor activity, and (2) an evaluation instrument of hand grip strength. The capability of the ejamar device to interact with exergames allows measuring various user parameters, such as isometric hand grip strength, pronation-supination angles, and linear movement acceleration in three axes, applicable to movements of the hand, arm, or forearm, depending on the type of exergame implemented. The remainder of this article is organized as follows. Section 2 presents a summary of related work. Section 3 describes the system architecture, the design process, and the main features of the proposed electromechanical device. Section 4 presents the results of the preliminary usability trials. Finally, the discussion and conclusions can be found in Section 5.