Silicon whole body sensors for medical applications-a glimpse of the future

The goal of this research was to develop a functional prototype of a patient wearable "solid state sensor shirt" (S4) for long term medical monitoring applications. The initial focus of this project was on electrocardiography. The S4 comprises clusters of miniature dry ECG electrodes embedded in the elastic mesh fabric. Each electrode cluster comprises of 8 closely spaced individual electrodes. High performance miniature AC-coupled amplifier circuits (0.04-1 kHz, CMMR=120 dB, Z/sub in/>1 G/spl Omega/) were used to measure body surface potentials from the electrode clusters. A digital signal processor coupled to the front-end amplifiers was used to continuously monitor the signals and noise content in multiple ECG leads formed by the electrodes from the respective clusters. The leads with highest signal to noise ratio were selected for a final composition of a standard 12 lead electrocardiogram. The primary clinical application of this research is monitoring of high-risk cardiac patients. Phase I research concentrated on prototyping the S4 that incorporated dry electrode clusters, incorporation of the biosignal amplifiers into a meshed stretchable fabric and quantitative evaluation of its clinical applicability. Future applications of S4 technology may include blood gas and vital signal sensing.