Development and Characterization of a Wearable, Low-cost, Focal Muscle Vibration Device for Neurorehabilitation Applications

Abstract

In the past decade, focal muscle vibration (FMV) has gained wide attention in neurological rehabilitation for its non-invasive nature, ease-of-use, and minimal side effects. Disorders like stroke, cerebral palsy, and multiple sclerosis have shown rehabilitatory benefits from FMV. The effectiveness of FMV is closely tied to device parameters, particularly the frequency and location of vibration stimulation. Despite a variety of devices available on the consumer market and research community, there are often insufficient details for robust device evaluation and its purported effects, leading to performance variability among different devices under similar input conditions. This study aims to develop a well-characterized FMV device that is usable and comparable across various application domains. The research focuses on the development and validation of a custom-designed wearable vibration device designed to deliver precisely controlled muscle stimulation. The device utilizes an eccentric-rotating-mass (ERM) motor design and features a three-dimensional computer-aided design (CAD) model, a 3D printed casing, and a curved surface for enhanced comfort during muscle contact. Characterization of the device involved establishing the relationship between input (battery) voltages and output (vibration) frequencies. Accelerometers and a microcontroller were used for precise frequency determination. The subsequent design of an electronic circuit allowed for user-controlled frequency adjustments, complemented by a pressure sensor ensuring consistent pressure during device use. The study concludes with a well-characterized vibration device holding promise for applications in neuromuscular research, and rehabilitation, owing to its precision, versatility, and user-friendly design.