Flow Detection in Open and Closed Shunt Valve Periods

This study is evaluating a new, noninvasive device designed to detect whether cerebrospinal fluid (CSF) is flowing through a surgically implanted shunt. CSF shunts are commonly used to treat hydrocephalus, but it can be difficult to tell whether a shunt is working properly without invasive testing or imaging that does not directly measure flow. The study device is a small, wireless sensor placed on the skin over the shunt tubing, typically near the collarbone. It uses gentle, controlled warmth to measure temperature changes that indicate whether fluid is flowing inside the shunt. The device does not break the skin and does not change a participant's medical care. This study will enroll children and adults who already have a CSF shunt and who do not have new or worsening symptoms of shunt malfunction. All participants will have a measurement taken while their shunt valve is at its usual prescribed setting. Some participants with programmable shunt valves will also have a second measurement taken after their valve is temporarily adjusted to a setting intended to stop or greatly reduce flow ("virtual off"). After this measurement, the valve will be returned to its prescribed setting. The study device results will not be shown to participants or their medical providers and will not be used to make treatment decisions. The goal of the study is to determine how well the device can distinguish between shunts that are allowing flow and those that are not. Participants will be monitored for a short period after device use and, if applicable, after any valve adjustment. The main risks of participation are mild skin irritation from the adhesive or temporary symptoms related to valve adjustment. Participants are not expected to receive a direct medical benefit, but the information gained may help improve future diagnosis of shunt function.