Epidermal electronics for noninvasive, wireless, quantitative assessment of ventricular shunt function in patients with hydrocephalus

Abstract

Hydrocephalus is a common and costly neurological condition caused by the overproduction and/or impaired resorption of cerebrospinal fluid (CSF). The current standard of care, ventricular catheters (shunts), is prone to failure, which can result in nonspecific symptoms such as headaches, dizziness, and nausea. Current diagnostic tools for shunt failure such as computed tomography (CT), magnetic resonance imaging (MRI), radionuclide shunt patency studies (RSPSs), and ice pack–mediated thermodilution have disadvantages including high cost, poor accuracy, inconvenience, and safety concerns. Here, we developed and tested a noninvasive, skin-mounted, wearable measurement platform that incorporates arrays of thermal sensors and actuators for precise, continuous, or intermittent measurements of flow through subdermal shunts, without the drawbacks of other methods. Systematic theoretical and experimental benchtop studies demonstrate high performance across a range of practical operating conditions. Advanced electronics designs serve as the basis of a wireless embodiment for continuous monitoring based on rechargeable batteries and data transmission using Bluetooth protocols. Clinical studies involving five patients validate the sensor’s ability to detect the presence of CSF flow (P= 0.012) and further distinguish between baseline flow, diminished flow, and distal shunt failure. Last, we demonstrate processing algorithms to translate measured data into quantitative flow rate. The sensor designs, fabrication schemes, wireless architectures, and patient trials reported here represent an advance in hydrocephalus diagnostics with ability to visualize flow in a simple, user-friendly mode, accessible to the physician and patient alike.

Continuous, noninvasive wireless monitoring of flow of cerebrospinal fluid through shunts in patients with hydrocephalus

“…As discussed previously 30,38 , α varies non-monotonically with flow rate, as shown in Fig. 2f, with a peak sensitivity at 0.07-0.1 ml/min for the designs reported here.…”

Wireless battery-free body sensor networks using near-field-enabled clothing

“…Current solutions for wireless sensor interconnection either require each sensor to be independently powered (such as with batteries) 11,[17][18][19][20][21][22][23] or have a very limited range of operation (few centimetres) [32][33][34][35][36][37][38][39] . Networks of skin-mountable sensors use.…”

“…Wireless technologies can be used to connect wearable sensors without physical constraints. In particular, radio-based wireless communication methods, such as Bluetooth and Wi-Fi, are widely used to enable sensors to wirelessly communicate around the body for monitoring health and providing real-time clinical notifications 11,[17][18][19][20][21][22][23][24] . Unlike wired interconnects, however, these radio-based technologies require each sensor to be separately powered, typically using rigid batteries or bulky energy harvesters.…”

Cyber–Physiochemical Interfaces

“…Copyright 2016, Springer Nature. Hydrocephalus monitoring image: Reproduced with permission . Copyright 2018, The Authors, published by AAAS.…”

“…Typical demonstration was the skin‐like pressure sensors based on pyramidal structures, the sensing principle of which is similar to pulse diagnosis in traditional Chinese medicine. To further fully utilize all the information for health indicators, various epidermal electrophysiological and biochemical sensors have appeared, such as electrocardiogram (ECG), electromyography (EMG), and glucose, lactate, and ionic biosensors . Therefore, epidermal biosensor opens a chemosensory window to monitor human internal status.…”