Journal of Ophthalmology / 2015 / Article / Fig 3

Research Article

Blood Pressure and Heart Rate Variability to Detect Vascular Dysregulation in Glaucoma

Figure 3

The method of Joint Symbolic Dynamics (JSD) quantifies the short-term bivariate nonlinear behavior (coupling) of blood pressure and heart rate. JSD transforms BBIs (beat-to-beat intervals) and diastolic or systolic blood pressure time series into symbol sequences of different words (3 successive symbols are one word) according to the pattern of change (increase or decrease) [14]. Top: as time series of BBI (in ms) and systolic blood pressure values (in mmHg). Middle: as symbol vector. Bottom: as word type matrix with BBI (columns); SP, systolic blood pressure (rows). With JSD1…JSD64 as coupling indices.