SBIR Phase I: Hardware and Software Development for Noninvasive, Wireless Flow Sensors for Patients with Hydrocephalus

The broader/commercial impact of this SBIR Phase I project outlines a development plan for a wireless, wearable sensor for noninvasive measurements in shunts in patients with hydrocephalus. Hydrocephalus is a common and costly condition caused by the accumulation of cerebrospinal fluid in the ventricles of the brain. It affects >1 million people in the US and is nearly always treated with the surgical implantation of a shunt to drain this excess fluid away from the brain. Unfortunately, shunts have extremely high failure rates (98% over ten years) and diagnosing shunt malfunction is confounded by its vague, nonspecific symptoms such as headaches and nausea. Additionally, there exists no direct way to measure flow through shunts. The proposed project would save the US healthcare system >$200 million annually in diagnostic costs and unnecessary hospital admissions. Moreover, it could be used to monitor shunt function at home, providing patients and their caregivers peace of mind. The materials science and mechanical engineering advances required to advance the project will fundamentally advance the development of wearable electronics for digital health. The proposed project relies on a set of concepts in materials science, mechanical engineering and fundamental studies of thermal transport phenomena to yield a soft, wireless, wearable device the thermal characterization of skin and soft tissue. Specifically, the integration of controlled, low-power thermal actuators and precise temperature sensors on a flexible circuit on the surface of the skin allows for the mapping of temperature and direction heat flow through near-surface epidermal layers. The flow of heat can be quantitatively correlated to both the presence and magnitude of underlying flow in a range of biological conduits, ranging from shunts to blood vessels. Moreover, the soft, silicone construction of the device presents a nonirritating, compliant interface to the surface of the skin. Quantitative measurements of thermal transport, in comparison to benchtop models and calculations will yield real-time flow rates, while a customized software application on a smartphone, communicating with a Bluetooth system-on-chip located on the device will collect store and analyze data in real-time, proving real-time feedback to physicians, patients and their caregivers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.