The PPG signal shows periodic peaks corresponding to the blood pulse waves arriving at the fingertip. The signal therefore has similar characteristics to the ECG signal.
The method of choice in BrainVision Analyzer 2 to identify markers of cardiac function is the pulse detection included in CB Correction (Transformations > Special Signal Processing > CB Correction). This transformation is designed to be applied to an ECG channel and detect the R-peak of the QRS complex. However, as characteristics of PPG and ECG signals are comparable, the detection can be used for pulse waves in the PPG signal as well.
The CB Correction should be used with the options “Use Peak Detection” and “Semiautomatic Mode”. As there is no need to apply a correction, the option “Write Only Markers” must be enabled. A prototypical pulse wave should be selected as template. It might be necessary to fit the pulse rate, correlation and amplitude triggers to the individual dataset to achieve a robust detection of the pulse wave peaks. However, semiautomatic mode allows one to start from a certain parameter set (like the default values) and to recalculate the detection on the fly if parameters need to be adapted.
Similar to ECG signals, you can also apply solutions to the PPG channel, for example, Marker Timing (Solutions > Views > Marker Timing) to check for the intervals between pulses. The resulting values can be exported with Generic Data Export (Export > Node Export > Generic Data). It is also possible to use the IBI Export (Solutions > Export > IBI Export) solution to export the inter-pulse intervals of the PPG signal to a text file.
If both ECG and PPG were measured and peaks have been determined in both signals, the so-called Pulse Transit Time can be approximated by measuring the distance between the R-peak markers and the PPG pulse wave markers. This can be done conveniently with the solution Write Markers (Solutions > Markers > Write Markers).
Alternatively, you may want to externally process the PPG signal. For this purpose, you could export the list of pulse wave markers as text or XML file via Markers Export (Export > Node Export > Markers). An overview of continuous blood pressure measurements as with PPG can be found in .