Portable Hugs: A Wearable Deep Pressure Application Device for Sensory Overstimulation

Autism Spectrum Disorder (ASD) is a developmental disability that impacts the way people with ASD behave, communicate, and interact with their world. In the US, approximately 5.5 million adults aged 18 and older have ASD, and 90% of them report atypical tactile sensitivity such as hypo- or hyper-stimulation (sensory overstimulation) (Dietz et al., 2020, Balasco et al., 2020). The standard of care for treating overstimulation often puts the burden of managing and alleviating symptoms on individuals with ASD. Treatments include some combination of behavioral modification (meditation, breathing, self-regulation), psychopharmacological treatment, and sensory based interventions (SBI), including deep pressure stimulation. Deep pressure stimulation is a person-specific intervention that involves the application of firm, gentle pressure, through weighted garments, swaddling, or hugging, at various points on the body. The intensity and duration of this pressure application is unique to an individual's care plan and appears to have benefit in the immediate improvement of their psychological state (Bestbier & Williams, 2017). In coordination with the Autism Treatment Center at Dallas and the undergraduate Engineering Projects in Community Service (EPICS) program at UT Dallas, the Sensory Cuff is developed to address the need for relief and comfort from overstimulation through contactless deep pressure stimulation. The Cuff is a wearable, mobile app-controlled device that facilitates collaboration between the wearer and caregiver to effectively manage sensory overstimulation. It is designed to be worn on the upper arm and is comprised of an inflatable air bladder encased in printed fabric. The control electronics are housed in a 3D printed enclosure, mounted on a custom-designed PCB, and consist of a microcontroller, digital pressure sensor, two DC pumps to inflate/deflate the bladder, electric solenoid valve, batteries, and an emergency stop switch. An iOS mobile application (app) programmed in SwiftUI enables remote control and communication with the Cuff through Bluetooth, allows the app user to set the target pressure, hold time, and indicate the mode of operation. App users, typically caregivers, can initiate a single inflate or deflate cycle with Free Run, or continuous, cyclic inflate and deflate with Cycle Run. In initial bench testing of the minimum viable prototype, the Cuff demonstrated functionality by completing 11 inflate/deflate cycles within a 15-minute period when set to a maximum target pressure of 1 psi above atmospheric pressure. Each inflate cycle is approximately 48s and deflate cycle is approximately 30s. Additionally, the Cuff has an adjustable length from 22-52 cm, to meet the arm circumference specifications set by the American Medical Association. The cuff costs approximately 180 USD to build. Finally, next steps in development include calibration to ensure delivered pressure is accurate to target pressure, requirements verification to evaluate functionality safety, and efficacy and, finally, pre-clinical testing to evaluate the impact of using the Sensory Cuff in treating overstimulation against a control action (i.e., behavioral modification). In conclusion, the Sensory Cuff is an accessible, interactive device that is poised to improve the quality of care in treating and managing sensory overstimulation by facilitating collaboration between individuals with ASD and their caregivers.