Autonomic nervous system responses in the intermediate band to cranial cutaneous stimulation.

Cardiovascular rhythms representing functional states of the autonomic nervous system (ANS) are insufficiently reflected by the current physiological model based on low and high frequency bands (LF, HF, resp.). An intermediate (IM) frequency band generated by a brainstem pacemaker was included in systemic physiological ANS analyses of forehead skin perfusion (SP), ECG, and respiration. Data of 38 healthy participants at T0 and T1 (+1 week) before, during, and following osteopathic cranial vault hold (CVH) stimulation were analyzed including momentary frequencies of highest amplitude, amplitudes in low (0.05-0.12 Hz), IM (0.12-0.18 Hz), and high (0.18-0.4 Hz) frequency bands, and established heart rate variability (HRV) metrics. During CVH, LF interval durations increased, whereas IM/HF band durations decreased significantly. Amplitudes increased significantly in all frequency bands. A cluster analysis found one response pattern dominated by IM activity (47% of participants) with highly stable 0.08 Hz oscillation to CVH, and one dominated by LF activity (0.10 Hz) at T0, increasing to IM activity at T1. Showing frequency ratios at ≈3:1, respiration was not responsible for oscillations in PPG during CVH. HRV revealed no significant responses. Rhythmic patterns in SP and respiration matched previous findings on a reticular "0.15 Hz rhythm". Involvement of baroreflex pathways is discussed as alternative explanation.

On the cardiorespiratory coordination assessed by the photoplethysmography imaging technique.

Cardiorespiratory coordination (CRC) probes the interaction between cardiac and respiratory oscillators in which cardiac and respiratory activity are synchronized, with individual heartbeats occurring at approximately the same temporal positions during several breathing cycles. An increase of CRC has previously been related to pathological stressful states. We studied CRC employing coordigrams computed from non-contact photoplethysmography imaging (PPGI) and respiratory data using the optical flow method. In a blocked study design, we applied the cold pressure test (CPT), water at ambient temperature (AWT), and intermittent resting conditions. In controls (no intervention), CRC remained on initial low levels throughout measurements. In the experimental group (AWT and CPT intervention), CRC decreased during AWT and CPT. Following both interventions, CRC increased significantly, with a rebound effect following AWT. In controls, HR increased steadily over time. CPT evoked a significant HR increase which correlated with subjective stress/pain ratings. The CRC increase following AWT correlated significantly with subjective pain (r = .79) and stress (r = .63) ratings. Furthermore, we observed a significant correlation (r = - .80) between mean RMSSD and mean duration of CRC, which further supports an association between autonomic state and CRC level. CRC analysis obtained from cutaneous tissue perfusion data therefore appears to be a sensitive and useful method for the study of CRC and ANS activity. Future studies need to investigate the physiological principles and clinical significance of these findings.

Validation of subjective manual palpation using objective physiological recordings of the cranial rhythmic impulse during osteopathic manipulative intervention.

Intermediate (IM) band physiology in skin blood flow exhibits parallels with the primary respiratory mechanism (PRM) or cranial rhythmic impulse (CRI), controversial concepts of osteopathy in the cranial field (OCF). Owing to inconsistent manual palpation results, validity of evidence of PRM/CRI activity has been questionable. We therefore tried to validate manual palpation combining instrumented tracking and algorithmic objectivation of frequencies, amplitudes, and phases. Using a standard OCF intervention, cranial vault hold (CVH), two OCF experts palpated and digitally marked CRI frequencies in 25 healthy adults. Autonomic nervous system (ANS) activity in low frequency (LF) and IM band in photoplethysmographic (PPG) forehead skin recordings was probed with momentary frequency of highest amplitude (MFHA) and wavelet amplitude spectra (WAS) in examiners and participants. Palpation errors and frequency expectation bias during CVH were analyzed for phases of MFHA and CRI. Palpated CRI frequencies (0.05-0.08 Hz) correlated highly with mean MFHA frequencies with 1:1 ratio in 77% of participants (LF-responders; 0.072 Hz) and with 2:1 ratio in 23% of participants (IM-responders; 0.147 Hz). WAS analysis in both groups revealed integer number (harmonic) waves in (very) low and IM bands in > 98% of palpated intervals. Phase analyses in participants and examiners suggested synchronization between MFHA and CRI in a subset of LF-responders. IM band physiology in forehead PPG may offer a sensible physiological correlate of palpated CRI activity. Possible coordination or synchronization effects with additional physiological signals and between examiners and participants should be investigated in future studies.

On the spatial phase distribution of cutaneous low-frequency perfusion oscillations.

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.

Neural correlates of fluctuations in the intermediate band for heart rate and respiration are related to interoceptive perception.

Supratentorial brain structures such as the insula and the cingulate cortex modulate the autonomic nervous system (ANS). The neural underpinnings of separate frequency bands for variability in cardiac and respiratory data have been suggested in explaining parasympathetic and sympathetic ANS modulation. As an extension, an intermediate (IM) band in peripheral physiology has been considered to reflect psychophysiological states during rest. Using functional magnetic resonance imaging (fMRI), we investigated the neural correlates associated with IM band variability in cardiac and respiratory rate and identified dissociable networks for LF, IM, and HF bands in both modalities. Cardiac and respiratory IM band fluctuations correlated with blood oxygen level-dependent (BOLD) signal in the mid and posterior insula and the secondary somatosensory area, that is, regions related to interoceptive perception. These data suggest that in addition to the commonly considered LF and HF bands, other frequency components represent relevant physiological constituents. The IM band may be instrumental for assessment of the CNS-ANS interaction. In particular, the relation between the IM band and interoception may be of physiological and clinical interest.

Presurgical assessment of bariatric patients with the Patient Health Questionnaire (PHQ)--a screening of the prevalence of psychosocial comorbidity.

BACKGROUND: Bariatric surgery has gained increasing relevance due to the dramatic rise in morbid obesity prevalence. A sound body of scientific literature demonstrates positive long-term outcome of bariatric surgery in decreasing mental and physical health morbidity. Still, there is a need for a manageable presurgical screening to assess major mental disorders. The aim of this study was to assess the frequency of common psychiatric syndromes in bariatric surgery candidates using a computerized version of the Patient Health Questionnaire (PHQ). METHODS: In a prospective cohort study from August 2009 to July 2011 morbidly obese individuals seeking bariatric treatment were evaluated for mental health disorders using the PHQ (computerized German version). RESULTS: A total of 159 patients were included in this study. The median age of participants was 42 years, the median BMI was 49 kg/m(2). The PHQ revealed a prevalence of 84 % for mental health disorders, 50 % of the participants had three or more mental health disorders. A high somatic symptom burden (46 %), depressive syndromes (62 %) and anxiety disorders (29 %) were the most frequent psychiatric syndromes. The median number of psychiatric syndromes was 3 for women and 1 for men (p = 0.007). No correlation between BMI and a single syndrome or the sum of syndromes was observed. CONCLUSION: 84 % of the patients seeking bariatric treatment were screened positive for at least one mental health disorder. The computerized PHQ with automated reporting appears to be a useful instrument for presurgical assessment of bariatric patients in routine medical settings.

Can contextual online exams in practical biomedical education increase comprehension and motivation?: a pilot project.

The exclusive reproduction of short-term learned and pool-based contents in examinations may impede development of in-depth understanding. This pilot project suggests an approach useful to overcome this shortcoming by enhancing students' motivation for comprehensive learning using automatically added contextual questions in electronic examinations. Installed in practical courses teaching pain physiology, digital data acquisition and examination workstations were interlinked via a network connection. The data acquisition software was substantiated by algorithms that evaluated data acquired before their transmission to examination workstations. These data were used by the assessment software operating on these workstations to automatically compose new examination questions. Examinations thus combined pool questions with newly generated questions with authentic digitized data from the preceding course. This helped confront students with questions based on their individual data that had resulted from the courses examined. Formative evaluation showed an increase in motivation and alertness for practical tasks and acquired results. This suggests usefulness of this setting in examining the preparation and comprehension of course contents. There is reason to assume that this approach is suitable to be transferred to other practical courses using digital acquisition of practical and examination data.

Self-efficacy in acutely traumatized patients and the risk of developing a posttraumatic stress syndrome.

Post traumatic stress disorder (PTSD) occurs across 15-20% of victims suffering physical injury. The occurrence of PTSD has been attributed to both the trauma and the victim's individual resources, such as resilience, coping strategies, and social support systems. In the present study, we explored the role of self-efficacy for cognitive self-regulation in the posttraumatic adaptation process of sixty-five patients immediately following trauma (T1) and approximately four months later (T2) assessing posttraumatic stress syndrome according to DSM-IV criteria. We hypothesized perceived self-efficacy as a predictor for an increased risk of developing posttraumatic stress symptoms. Self-efficacy measured immediately following trauma correlated significantly with the development of posttraumatic stress syndromes. This finding suggests that the evaluation of cognitive adaptation to trauma is a helpful marker for clinical outcome assessment and can therefore be used for the identification of patients needing psychotherapeutic intervention.

[From the Gestaltkreis to synergetics: irreversible structural and dynamic functional couplings]. / Vom Gestaltkreis zur Synergetik: Die Bedeutung irreversibel-struktureller und dynamisch-funktioneller Kopplungen.

With the present contribution, we attempt to merge the work of several generations of physiology and psychosomatics. The common denominator in an array of observation levels appear in these works as the relationship between irreversible-structural and dynamic-functional couplings and synchronisations. In this context, studies on the level of the common brainstem system appear to be the base for a neuro-bio-psychic self-organisation. Studies culled from psychosomatics of Heidelberg, notably the Gestaltkreis theory, the Methodenkreis (methodological loop), the Bipersonalität (bipersonality), and the Simultandiagnostik (simultaneous diagnostics) exhibit the origin of complex functions which have been analyzed and quantified employing nonlinear methods developed in synergetics. Relevance of coupling and synchronisation, desynchronisation, resp., is, however, not limited to the scope of psychosomatic medicine. Fixed or functional, they are essential constituents to neurophysiological processes, such as association, dissociation, resp. This equally holds for evidence based medicine which is to benefit from any dynamic process analysis.

The neurofunctional mechanisms of traumatic and non-traumatic memory in patients with acute PTSD following accident trauma.

Neurofunctional alterations in acute posttraumatic stress disorder (PTSD) and changes thereof during the course of the disease are not well investigated. We used functional magnetic resonance imaging to assess the functional neuroanatomy of emotional memory in surgical patients with acute PTSD. Traumatic (relative to non-traumatic) memories increased neural activity in the amygdala, hippocampus, lateral temporal, retrosplenial, and anterior cingulate cortices. These regions are all implicated in memory and emotion. A comparison of findings with data on chronic PTSD suggests that brain circuits affected by the acute disorder are extended and unstable while chronic disease is characterized by circumscribed and stable neurofunctional abnormalities.

Cardiorespiratory effects induced by vagus nerve stimulation in epileptic children.

Vagus nerve stimulation (VNS) is used in pharmaco-resistant epilepsy to decrease the number of seizures. Although it is well known that VNS affects respiration, there are only a few reports concerning an effect of VNS on heart rate or heart rate variability (HRV). We investigated the relationship between respiratory frequency and the high frequency (HF) domain of the discrete Fourier transform (DFT) of the RR interval function during night sleep recordings of ten subjects treated with VNS. Our results show that VNS shifts the frequency of maximal power spectrum density (PSD) in the HF-band, decreases the related PSD and induces a partial cardiorespiratory decoupling.

Cardiovascular rhythms in the 0.15-Hz band: common origin of identical phenomena in man and dog in the reticular formation of the brain stem?

Selected examples from experiments in humans and dogs with time series of reticular neurons, respiration, arterial blood pressure and cutaneous forehead blood content fluctuations were analysed using multiscaled time-frequency distribution, post-event-scan and pointwise transinformation. We found in both experiments a "0.15-Hz rhythm" exhibiting periods of spindle waves (increasing and decreasing amplitudes), phase synchronized with respiration at 1:2 and 1:1 integer number ratios. At times of wave-epochs and n:m phase synchronization, the 0.15-Hz rhythm appeared in heart rate and arterial blood pressure. As phase synchronization of the 0.15-Hz rhythm with respiration was established at a 1:1 integer number ratio, all cardiovascular-respiratory oscillations were synchronized at 0.15 Hz. Analysis of a canine experiment supplied evidence that the emergence of the 0.15-Hz rhythm and n:m phase synchronization appears to result from a decline in the level of the general activity of the organism associated with a decline in the level of activity of reticular neurons in the lower brainstem network. These findings corroborate the notion of the 0.15-Hz rhythm as a marker of the "trophotropic mode of operation" first introduced by W.R. Hess.

[Synergetics of hypnoid relaxation]. / Synergetik der hypnoiden Relaxation.

The Autogenic Training (AT) is a well established relaxation technique and psychotherapy tool. We report the use of nonlinear routines, the Multi-scaled Time-Frequency-Distribution (mTFD) for the graphical display of vegetative rhythms, and Post-Event-Scan (PES) for the direct visual identification of coupling between physiological subsystems. Applying these methods to time series of respiration, arterial blood pressure, and cutaneous forehead blood content fluctuations in controls (n = 11) or AT-experts (ATE, n = 11) induced psychomotor drive reduction during orthostatic stress allowed the instantaneous identification of a 0.15 Hz-rhythm. This rhythm prevailed in ATE significantly longer resulting a significantly robust 1 : 1 coupling between cutaneous blood content fluctuations and respiration. Consequently, we hypothesize that the "0.15 Hz-rhythm" in the cutaneous blood content fluctuations described previously which was associated with the subjective experience of profound psychomotor relaxation reflects an order-order transition in peripheral signals of central nervous origin. Results produced with the aid of these analytic tools support the efficacy of the AT induced, synergetic relaxation response.

Neural processing of traumatic events in subjects suffering PTSD - a case study of two surgical patients with severe accident trauma.

Neuroimaging research on the neurobiology of chronic PTSD (posttraumatic stress disorder) has revealed structural and functional alterations primarily affecting areas of the medial temporal lobe (hippocampus, amygdala, and parahippocampal gyrus) and the frontal cortex known to be associated with the disorder. Using functional magnetic resonance imaging (fMRI), the present study studied the functional neuroanatomy of traumatic and non-traumatic emotional memory in two surgical patients who had sustained severe accident trauma. While patient 1 had developed acute PTSD following the traumatic event, patient 2 (control) did not. When confronted with traumatic (relative to negatively valenced non-traumatic) memory, the PTSD patient exhibited evidence for increased neural activity in the right and the left superior temporal lobe, the amygdala, the left angular gyrus, and the medial frontal gyrus, while the non-PTSD patient exposed to identical conditions showed increased activations in frontal and parietal regions. Both patients exhibited identical activation patterns when recalling non-traumatic memories relative to neutral memories. It is concluded that the pronounced activation patterns in the PTSD patient may be considered specific for acute PTSD, involved with the emotional arousal and the vivid visual recollections typical for the acute phase of the disorder.