The variability of the photoplethysmographic signal - a potential method for the evaluation of the autonomic nervous system

Abstract

The heart rate variability is composed of low- and high-frequency fluctuations, which are mediated by the sympathetic and the parasympathetic nervous systems. The baseline and the amplitude of the photoplethysmographic (PPG) signal also show fluctuations in the same frequencies. In the current study, PPG examinations were performed on the fingers of normal subjects and diabetic patients, and three parameters were derived from each PPG pulse: the baseline of the pulse, its amplitude and its period (which is equal to the heart period). The level of the variability of each PPG pulse parameter was measured by the ratio of the standard deviation of the parameter to its mean value. The level of the low-frequency fluctuations for the PPG amplitude and for the heart cycle period did not differ between males and females, but was lower for diabetic patients, indicating lower activity of the autonomic nervous system. The curves of the baseline and the amplitude of the PPG signal for the non-diabetic subjects showed high correlation between the left and the right hands. For most of the diabetic patients the right-left correlation coefficients were significantly lower than those for the non-diabetic subjects. Our initial results have shown that the variability of the PPG parameters shows promise for the assessment of the function of the autonomic nervous system.

Vasodilatation médiée par sympathectomie: une étude randomisée de détermination de la concentration de bupivacaïne péridurale

“…As reported previously, the baseline (BL) and amplitude (AM) signal was digitally identified, quantified, and averaged over successive pulsations for each individual pulse in the PPG waveform tracing. [20][21][22] It should be noted that PPG waveform analysis was performed ''off-line'' after completion of the study; thus, if baseline or movement artefact was noted, it was not possible to improve data signal quality. In these cases, the PPG waveform was not accepted for analysis.…”

Non-intrusive Physiological Monitoring for Affective Sensing of Computer Users

“…At about the same point in time, it was proposed that the variations observed in the "Blood Volume Pulse" (BVP) signal, which can be recorded from the subject's finger using an infrared photoplethysmograph (PPG), may also be appropriate to evaluate the ANS function [Nitzan et al, 1998]. More recently, it has been confirmed that the BVP signal from a photoplethysmograph may provide basic information about the heart rate and its variability [Giardano et al, 2002] in a non-intrusive form.…”

Finger and forehead PPG signal comparison for respiratory rate estimation based on pulse amplitude variability

“…PPG has been applied in many different clinical settings, including the monitoring of blood oxygen saturation, heart rate and its variability, giving information about the autonomic nervous system, blood pressure, cardiac output and respiration [2], [3].…”