Using Accelerometric and Gyroscopic Data to Improve Blood Pressure Prediction from Pulse Transit Time Using Recurrent Neural Network

We propose a method for estimating blood pressure (BP) non-invasively from electrocardiogram (ECG) and photoplethysmogram (PPG) signals. This method has potential to be used as a continuous form of BP estimation. Along with these signals, to our knowledge, for the first time in the BP measurement studies, we included accelerometric and gyroscopic signals from a wearable device to compensate for motion during continuous BP prediction. Our prediction model is a long-short-term-memory (LSTM) architecture of a recurrent neural network (RNN), which accommodates the multiscale temporal dependency between the sequential raw signal values and the corresponding systolic and diastolic BP values. We performed a study with 50 healthy volunteers. The mean difference ± standard deviation (SD) of the RNN-based approach were 0.02±4.8 for SBP and 1.5±3.7 for DBP in seated position & 2.6±6.0 for SBP and 2.7±4.5 for DBP while walking. These values meet current validation standard requirements for measurement accuracy. Our experiments also demonstrate that the proposed RNN-based approach outperformed the classical linear regression model for BP prediction.