Figure 8 - uploaded by Christian S. Pilz
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The box plot visualization of the sustained attention reaction time in seconds over the correlation range between the dominant EEG occipital alpha power and the PPGI heart rate variability in terms of LF/HF ratio.
Source publication
We investigate the regulation of human brain arousal in the central nervous system and its synchronization with the autonomic nervous system affecting the facial dynamics and its behavioral gestalt. A major focus is made on the sensing observable during natural human eye to eye communication. Although the inner state of the autopoietic system is de...
Context in source publication
Context 1
... computed the reaction time for the sustained attention and corresponding tap error behavior for both features over the entire range of correlations again. In Figure 8 the box plot of the sustained attention reaction time in seconds is visualized. For higher negative correlation values the reaction time is larger. ...
Citations
... The rigid regulation is often observed during depressive episodes and the labile regulation during manic episodes. A statistical link to facial dynamics was studied recently [10]. ...
... Many biological systems can be described relatively well as open thermodynamic processes [30]. The alternation between determinism and complexity of this autopoietic system [31] by means of its dissipative structures [32] on an abstract level involves merely certain different states of energy [10]. The transformation of energy into a new state can then be formulated informationtheoretically [33]. ...
... More recent studies have analyzed vigilance regulation while one's eyes are open. Here the statistical relation between the facial behaviour, the vegetative nervous system and performance-based vigilance measurements are used as a multivariate construct to directly predict brain arousal regulation as an indicator for estimating tiredness [10]. In this paper, the term vigilance will be also used as a surrogate measure which is further investigated in the domain of observable behaviour from the human face. ...
We study the statistical properties of facial behaviour altered by the regulation of brain arousal in the clinical domain of psychiatry. The underlying mechanism is linked to the empirical interpretation of the vigilance continuum as behavioral surrogate measurement for certain states of mind. Referring to the classical scalp-based obtrusive measurements, we name the presented method Opto-Electronic Encephalography (OEG) which solely relies on modern camera-based real-time signal processing and computer vision. Based upon a stochastic representation as coherence of the face dynamics, reflecting the hemifacial asymmetry in emotion expressions, we demonstrate an almost flawless distinction between patients and healthy controls as well as between the mental disorders depression and schizophrenia and the symptom severity. In contrast to the standard diagnostic process, which is time-consuming, subjective and does not incorporate neurobiological data such as real-time face dynamics, the objective stochastic modeling of the affective responsiveness only requires a few minutes of video-based facial recordings. We also highlight the potential of the methodology as a causal inference model in transdiagnostic analysis to predict the outcome of pharmacological treatment. All results are obtained on a clinical longitudinal data collection with an amount of 99 patients and 43 controls.
... The control group showed a clear increase for IM band phase desynchronizations by the end of the experimental session which may be related to the duration of relaxation experienced as tedious since the optimal duration of relaxation should be limited to 7 min 55 . This is reason to assume the present methodology ideally sensitive for the analysis of cutaneous responses qualifying it as a complementary tool for non-invasive diagnosis compared to other evaluation methods, e.g., in the spectral amplitude domain 56,57 , or time-domain analysis 58 . ...
Distributed cutaneous tissue blood volume oscillations contain information on autonomic nervous system (ANS) regulation of cardiorespiratory activity as well as dominating thermoregulation. ANS associated with low-frequency oscillations can be quantified in terms of frequencies, amplitudes, and phase shifts. The relative order between these faculties may be disturbed by conditions colloquially termed ‘stress’. Photoplethysmography imaging, an optical non-invasive diagnostic technique provides information on cutaneous tissue perfusion in the temporal and spatial domains. Using the cold pressure test (CPT) in thirteen healthy volunteers as a well-studied experimental intervention, we present a method for evaluating phase shifts in low- and intermediate frequency bands in forehead cutaneous perfusion mapping. Phase shift changes were analysed in low- and intermediate frequency ranges from 0.05 Hz to 0.18 Hz. We observed that time waveforms increasingly desynchronised in various areas of the scanned area throughout measurements. An increase of IM band phase desynchronization observed throughout measurements was comparable in experimental and control group, suggesting a time effect possibly due to overshooting the optimal relaxation duration. CPT triggered an increase in the number of points phase-shifted to the reference that was specific to the low frequency range for phase-shift thresholds defined as π/4, 3π/8, and π/2 rad, respectively. Phase shifts in forehead blood oscillations may infer changes of vascular tone due to activity of various neural systems. We present an innovative method for the phase shift analysis of cutaneous tissue perfusion that appears promising to assess ANS change processes related to physical or psychological stress. More comprehensive studies are needed to further investigate the reliability and physiological significance of findings.
A key goal of cognitive neuroscience is to better understand how dynamic brain activity relates to behavior. Such dynamics, in terms of spatial and temporal patterns of brain activity, are directly measured with neurophysiological methods such as EEG, but can also be indirectly expressed by the body. Autonomic nervous system activity is the best-known example, but, muscles in the eyes and face can also index brain activity. Mostly parallel lines of artificial intelligence research show that EEG and facial muscles both encode information about emotion, pain, attention, and social interactions, among other topics. In this study, we examined adults who stutter (AWS) to understand the relations between dynamic brain and facial muscle activity and predictions about future behavior (fluent or stuttered speech). AWS can provide insight into brain-behavior dynamics because they naturally fluctuate between episodes of fluent and stuttered speech behavior. We focused on the period when speech preparation occurs, and used EEG and facial muscle activity measured from video to predict whether the upcoming speech would be fluent or stuttered. An explainable self-supervised multimodal architecture learned the temporal dynamics of both EEG and facial muscle movements during speech preparation in AWS, and predicted fluent or stuttered speech at 80.8% accuracy (chance=50%). Specific EEG and facial muscle signals distinguished fluent and stuttered trials, and systematically varied from early to late speech preparation time periods. The self-supervised architecture successfully identified multimodal activity that predicted upcoming behavior on a trial-by-trial basis. This approach could be applied to understanding the neural mechanisms driving variable behavior and symptoms in a wide range of neurological and psychiatric disorders. The combination of direct measures of neural activity and simple video data may be applied to developing technologies that estimate brain state from subtle bodily signals.
This chapter presents the contactless vital signs monitoring through Continuous-Waves (CW) radar sensor. The chapter is divided into two parts: contactless vital signs monitoring through CW radar sensors and contactless vital signs monitoring through frequency-modulated Continuous-Waves (FMCW) radar sensors. The theory and signal-processing algorithm of the radar are introduced. The architectures of the CW/FMCW radar systems are simple, which facilitates the integration of radar technology into compact devices. Commercial CW/FMCW radar front-end transceivers are widely available. With the advantage of strong environmental adaptability, low-power consumption, and penetrability, CW/FMCW radars are promising for contactless vital signs monitoring application. This chapter introduces their potential application in cardiopulmonary monitoring, cancer medical application, and indoor human tracking.
Most of the work related to imaging photoplethysmography (iPPG) has its focus on methodological developments. To date, only few investigations addressed clinical applications. This chapter reviews the clinical usability of the iPPG. We present a number of potential applications together with their clinical background and relevant works. Covered applications comprise iPPG's use for patient monitoring and diagnostic applications beyond patient monitoring, particularly based on iPPG's capability for two-dimensional analyses of cutaneous perfusion. Finally, we provide an outlook on future clinical use cases and required developments.
