Abstract
Acquisition of biosignals is particularly valuable if uninterrupted data streams are collected over weeks or months without gaps. This is currently only possible with devices that feature long battery life and interfaces such as belts and straps that result in substantial limitations for signal fidelity, sensor location, wear comfort and user retention. State of the art patch-type wearables provide advanced sensing modalities, however, they require adhesives that need to frequently be replaced because of epidermal turnover and pose related limits for chronic operation. This review explores the value of chronic data streams to diagnostics and therapeutics with a detailed dissection of current sensors for chronic applications, system level architectures, sensing modalities and electronic concepts that enable continuous 24/7 high-fidelity insight into physiology.