Oscillometric blood pressure estimation using principal component analysis and neural networks

Estimation of systolic and diastolic pressures from the oscillometric waveform is a challenging task in noninvasive electronic blood pressure (BP) monitoring devices. Since the conventional oscillometric algorithms cannot model and extract the complex and nonlinear relationship that may exist between BP and oscillometric waveform, artificial neural networks (NNs) have been proposed as a possible alternative. However, the research on this topic has been limited to some simple architectures that directly estimate the BP from raw oscillation amplitudes (OAs). In this paper, we propose principal component analysis as a preprocessing step to decorrelate the OAs and extract the most effective components. Two architectures of NNs, namely, feed-forward and cascade-forward, are employed to estimate the BP using the preprocessed OAs. The networks are trained using the gradient descent with momentum and adaptive learning rate backpropagation algorithm and tested on a dataset of 85 BP waveforms. The performance is then compared with that of the conventional maximum amplitude algorithm and already published NN-based methods. It is found that the proposed networks achieve lower values of mean absolute error and standard deviation of error in estimation of BP compared with the other studied methods.