Shoulder Proprioception Device (S.P.D.): A Novel Design for Measuring Shoulder Joint Proprioception

Shoulder injuries are a serious and costly issue, particularly in physically intensive professions like athletics and the military. Previous data indicates a dangerous feedback mechanism between reduced shoulder proprioception due to previous injury and higher probability of re-injury due to reduced proprioception. It is therefore important for organizations to possess a device that can accurately and efficiently evaluate and track an individual’s shoulder proprioception, especially following injury. Existing technologies that fill this role are generally impractical or do not quantify proprioception to the necessary levels of accuracy. The Shoulder Proprioception Device (SPD) therefore strives to measure and quantify three-dimensional shoulder proprioception in a highly accurate, user-friendly, and cost-effective manner. This device employs two Inertial Measurement Units (IMUs) with nine degrees-of-freedom attached to the lateral and frontal sides of the upper arm. These sensors are connected to a microcontroller board with a touch screen and datalogger. The screen displays the shoulder angles in real-time and allows the user to store discrete angle positions for further analysis through the data-logger. The system is compact (390 cubic centimeter volume), light (0.34 kilograms), and cost effective ($179 per unit). This device is capable of measuring, in a total procedural time of seven minutes, shoulder proprioception within two degrees of accuracy along the three anatomical planes of motion: sagittal flexion/extension, frontal abduction/adduction, and transverse abduction/adduction. This device is able to both aid upper extremity research and provide data to those making return to duty decisions following injury.