114
H. Schmid-Schönbein
7.1 Introduction: A Short Outline of the Problem
of Uncovering “Order” in Apparently “Chaotic” Time
Series as They are Recorded in PPG and LDA
Measurements
Fundamental rule of physiological cooperativity can be corroborated by the use of
the “double plot technique”. While not allowing to simply calculating the true power
of each spectral contribution to the overall energy content, the combined display of
frequency chromatographs and the time series made it possible to identify distinct
frequency and amplitude domains reflecting not only the cardiac activity and that of
the neuronal vasoconstrictor effects.
Furthermore, it clearly showed that there are periodically modulated cutaneous
and mucosal microvascular activities passively following the fluctuations of arterial
blood pressure on the one hand and by ventilation-related events (that require more
detailed study). Thus, in applying both parts of the “double plots”, it has become
possible to identify patients with severe inflammation of the gingival mucosa which
could not be separated from healthy controls on the basis of the Laser-Doppler signal.
Such pragmatic success prompted the development of more advanced data
compression techniques shortly presented. This chapter was previously published
in [1].
The modes of perfusion of the microvasculature, i.e. the instantaneous movement
patterns and the RBC content of vessels vary considerably, being influenced by at
least four independent processes, namely
• the periodic cardiac activity influencing arterial driving pressure,
• the periodic respiratory activity influencing the pressure in the venous capacitance
vessels,
• the periodically modulated activity of the efferent sympathetic nervous system
and
• the periodically varying “myogenic tone” of smooth muscle, known to be strongly
influenced of the action of gravity on the transmural pressure, and thence the
tensilation of the vascular walls as “stimulus” for myogenic contraction (v.i.).
While occasionally, the overall “activity fluctuations” have been suspected to
reflect “chaoticity”, more detailed studies employing rigorous criteria for critical
dependency on initiating conditions, systematic divergence of trends (or the magnitude of Lyapunov exponents) and tests of multidimensionality have disproved this
insinuation (see, for example, Coluantani and Intagliatta. Therefore, our group has
approached this topic under a somewhat different logic, namely that developed in
physiological synergetics. In the previous publication from our own group, performed
in the attempt to comprehend the true nature of the well-known (yet undefined) “flux
motion” in Laser-Doppler recordings, we combined frequency analysis of the movement patterns with the frequency analysis of the blood content patterns (obtained by
simple photoplethysmography) and scrutinised the details of their “temporal order”
(in short the complex qualitative patterns) rather than the means of pressure, flow or
H. Schmid-Schönbein
7.1 Introduction: A Short Outline of the Problem
of Uncovering “Order” in Apparently “Chaotic” Time
Series as They are Recorded in PPG and LDA
Measurements
Fundamental rule of physiological cooperativity can be corroborated by the use of
the “double plot technique”. While not allowing to simply calculating the true power
of each spectral contribution to the overall energy content, the combined display of
frequency chromatographs and the time series made it possible to identify distinct
frequency and amplitude domains reflecting not only the cardiac activity and that of
the neuronal vasoconstrictor effects.
Furthermore, it clearly showed that there are periodically modulated cutaneous
and mucosal microvascular activities passively following the fluctuations of arterial
blood pressure on the one hand and by ventilation-related events (that require more
detailed study). Thus, in applying both parts of the “double plots”, it has become
possible to identify patients with severe inflammation of the gingival mucosa which
could not be separated from healthy controls on the basis of the Laser-Doppler signal.
Such pragmatic success prompted the development of more advanced data
compression techniques shortly presented. This chapter was previously published
in [1].
The modes of perfusion of the microvasculature, i.e. the instantaneous movement
patterns and the RBC content of vessels vary considerably, being influenced by at
least four independent processes, namely
• the periodic cardiac activity influencing arterial driving pressure,
• the periodic respiratory activity influencing the pressure in the venous capacitance
vessels,
• the periodically modulated activity of the efferent sympathetic nervous system
and
• the periodically varying “myogenic tone” of smooth muscle, known to be strongly
influenced of the action of gravity on the transmural pressure, and thence the
tensilation of the vascular walls as “stimulus” for myogenic contraction (v.i.).
While occasionally, the overall “activity fluctuations” have been suspected to
reflect “chaoticity”, more detailed studies employing rigorous criteria for critical
dependency on initiating conditions, systematic divergence of trends (or the magnitude of Lyapunov exponents) and tests of multidimensionality have disproved this
insinuation (see, for example, Coluantani and Intagliatta. Therefore, our group has
approached this topic under a somewhat different logic, namely that developed in
physiological synergetics. In the previous publication from our own group, performed
in the attempt to comprehend the true nature of the well-known (yet undefined) “flux
motion” in Laser-Doppler recordings, we combined frequency analysis of the movement patterns with the frequency analysis of the blood content patterns (obtained by
simple photoplethysmography) and scrutinised the details of their “temporal order”
(in short the complex qualitative patterns) rather than the means of pressure, flow or