Fig. 3.

Signal processing and feature extraction block diagram, with example data shown. Two electrocardiogram (ECG)-derived respiration signals were fused with the respiratory effort (RSP) signal for respiration rate, inspiration time, and expiration time estimation. From these three measures, an additional three variability measures were extracted by computing an interquartile range (IQR) time series for each on a 300 s moving window basis with a 299 s overlap. Example patient data are shown before, during, and after an example administration of transcutaneous cervical vagus nerve stimulation (tcVNS).