Changes In Autonomic Nervous System Research Articles

(947): Skin potential as a correlate of moderate to severe chronic pain - a case report

There exists a perceived need for an objective measure of pain and pain relief. A device which has been used in veterinary medicine performs bilateral measurements of the natural electric charge of the skin, skin potential (SP), to detect distinctive asymmetries caused by the autonomic nervous system (ANS) as it responds to moderate to severe persistent pain. SP has previously been used to accurately indicate ANS changes. The goal of this study was to see if this device might provide pain assessment in humans.

Association between nitrogen dioxide and heart rate variability in a susceptible population

Panel studies have shown a consistent association between changes in the cardiac autonomic nervous system with particulate matters (PM) but less with gaseous pollutants. This study examined the linkage between nitrogen dioxide (NO2) and heart rate variability (HRV) in a susceptible population. We recruited a panel of 83 patients from the National Taiwan University Hospital Cardiology Clinic to measure their 24-h HRV by ambulatory electrocardiography. Thirty-nine patients had coronary heart disease (CHD) and another 44 patients had more than one major CHD risk factor. Ambient concentrations of NO2, sulphur dioxide (SO2), carbon monoxide (CO), ozone, and PM less than 10 microm in diameter (PM10) at each participant's close-by monitoring station were used to represent study participants' exposures. We used linear mixed-effects models to analyse the association between individual air pollutants and log10-transformed HRV, with key personal and environmental attributes and co-pollutants being adjusted. We found that an increase in 10 ppb NO2 at 4-h to 8-h moving averages was associated with 1.5-2.4% decreases in the standard deviation of all normal-to-normal intervals (SDNN) in our participants. For every 10 ppb NO2 at 5 and 7-h moving averages, our participants' low frequency was decreased by 2.2 and 2.5%, respectively. In contrast, HRV was not associated with PM10, CO, SO2, or O3. Increasing NO2 exposure was found to be associated with decreasing SDNN and low frequency in susceptible populations.

Topological changes of the human autonomic cardiac nervous system in individuals with a retroesophageal right subclavian artery: two case reports and a brief review

The topological changes of the human autonomic cardiac nervous system in two cadavers with a retroesophageal right subclavian artery (Rersa) were compared with the normal autonomic cardiac nervous system. The following new results were obtained in addition to the conventional deficient finding of the right recurrent laryngeal nerve. (1) Right superior cardiac nerves arising from the superior cervical ganglion were consistently observed in both cadavers, in addition to the right thoracic cardiac nerves along the Rersa. (2) A segmental accompanying tendency of the right cardiac nerves was recognized: the cardiac nerves arising from the sympathetic trunk cranial to the middle cervical ganglia ran along with the right common carotid artery, whereas the cardiac nerves arising from the sympathetic trunk caudal to the vertebral ganglion ran along the Rersa. (3) The right thoracic cardiac nerves, which have never been observed to accompany the normal right subclavian artery, ran along the proximal part of the Rersa. According to previous reports of individuals with the Rersa, a thick right thoracic cardiac nerve is commonly observed instead of a right superior cardiac nerve. However, all the cardiac nerves were recognized in both the individuals described in the present report. Therefore, we strongly disagree with the previous idea that the origin of the right cardiac nerves from the sympathetic trunk and ganglia is shifted caudally in individuals with the Rersa. The topological changes of the autonomic cardiac nervous system in two cases of Rersa also reflected spatial changes of great arteries.

Physically Abused Children's Regulation of Attention in Response to Hostility

The present study examines the effects of early emotional experiences on children's regulation or strategic control of attention in the presence of interpersonal hostility. Abused children's reactions to the unfolding of a realistic interpersonal emotional situation were measured through multiple methods including autonomic nervous system changes and overt behavioral performance. Although physically abused and non-physically abused 4-year-old children did not differ in terms of their baseline levels of arousal, marked differences in physically abused children's regulatory responses to background anger emerged. These data suggest that the emergence of anger leads to increases in anticipatory monitoring of the environment among children with histories of abuse. Results are discussed in terms of risk factors in the development of psychopathology.

The short term effect of atlanto-axial high velocity low amplitude manipulation with cavitation on Edge Light Pupil Cycle Time

Background Edge Light Pupil Cycle Time (ELPCT) is a measure of the pupillary light reflex mediated via the autonomic nervous system (ANS). ELPCT is a measurable constant, unaffected by eye measured (i.e. left versus right eye), gender, visual acuity, refractive error, eye colour and pupil size. Previous research suggests that spinal manipulation techniques can produce distant effects mediated in part by the ANS. Objective To investigate the immediate effects of atlanto-axial high velocity low amplitude manipulation on ELPCT. Design A three group randomised controlled study. Methods Thirty participants (mean age = 23.8) without eye, central or autonomic nervous system pathology had their ELPCT measured in both eyes pre- and post-manipulation. The manipulation technique used was a high velocity low amplitude (HVLA) rotatory thrust, with the applicator localised to the atlanto-axial joint on the left ( n = 10) or right ( n = 10) determined randomly. All HVLA manipulations were associated with audible cavitation. The control group ( n = 10) underwent the same protocol, including pre-positioning for the manipulation, but without the thrust. Results ELPCT measures demonstrated a significant decrease between groups ( P = 0.004) and between groups according to eye measured ( P = 0.022). Significant decreases between pre- and post-manipulation measures of ELPCT indicated an association between side manipulated and eyes, with right-sided manipulation producing a decrease in ELPCT in the right eye ( P = 0.001) and a left-sided manipulation producing a decrease in the left eye ( P = 0.013). No other significant changes were observed. Conclusion ELPCT, mediated via the ANS, is directly influenced by HVLA manipulation with cavitation to the atlanto-axial joint. The ANS changes observed in this study demonstrated a unilateral response to HVLA manipulation.

The Different Effects of Intravenous Propofol and Midazolam Sedation on Hemodynamic and Heart Rate Variability

Heart rate (HR) and arterial blood pressure (BP) changes have been reported during conscious sedation with propofol and midazolam. One potential mechanism to explain these changes is that propofol and midazolam affect HR and BP via changes in the cardiac autonomic nervous system. Two specific hypotheses were tested by HR variability analysis: 1) propofol induces predominance of parasympathetic activity, leading to decreased HR and BP, and 2) midazolam induces predominance of sympathetic activity, leading to increased HR and decreased BP. Thirty dental patients were included in a prospective, randomized study. HR, BP, low frequency (LF), high frequency (HF), and entropy were monitored during the awake, sedation, and recovery periods and depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation score. Propofol induced a significant decrease in total power (503 +/- 209 ms(2)/Hz versus 162 +/- 92 ms(2)/Hz) and LF/HF ratio (2.5 +/- 1.2 versus 1.0 +/- 0.4), despite the absence of any change in HR during the sedation period compared with baseline. Midazolam decreased normalized HF (34 +/- 10% versus 10 +/- 4%) but did not significantly change LF/HF ratio (2.3 +/- 1.1 versus 2.2 +/- 1.4) and increased HR in the sedation period. Compared with baseline, propofol was associated with a significant increase in normalized HF in the recovery period (34 +/- 11% versus 44 +/- 12%) and a significant decrease in HR, whereas midazolam was associated with an increase in LF/HF ratio (2.3 +/- 1.1 versus 3.7 +/- 1.8) with no change in HR. These results indicated a dominant parasympathetic effect of propofol and a dominant sympathetic effect of midazolam in both periods. These results should be considered during conscious sedation, especially in patients at risk of cardiovascular complications.

Loss of efferent vagal activity in acute schizophrenia

An increased heart rate has been reported in schizophrenia. It is unclear whether this is due to disease-related autonomic nervous system changes or a side effect of antipsychotic medication. Altered cardiac autonomic function might to some extent account for the elevated cardiovascular mortality rate of schizophrenic patients. We assessed heart rate variability (HRV) in 30 acute unmedicated schizophrenic patients and matched controls. Patients were re-investigated 2–4 days after initiation of treatment to assess effects of medication. Our study demonstrates that non-medicated schizophrenic patients were significantly different in heart rate (increase) and parasympathetic parameters (loss of efferent vagal activity) at rest and during deep respiration. No significant effect was found after initiation of neuroleptic therapy. We found a correlation between duration of disease and parasympathetic parameters as well as very low frequency power (VLF) and delusion (SAPS subscale). These data suggest that schizophrenia is accompanied by a loss of vagal efferent activity, probably due to disturbed cortical–subcortical circuits modulating the autonomic nervous system in acute psychosis. The definite mechanisms by which vagal activity might be suppressed in schizophrenia are unknown. Parasympathetic hypoactivity might increase the risk for sudden cardiac death and arrhythmias in this disease. Future studies are warranted to investigate the interaction between cardiac autonomic function and schizophrenia and to identify patients on risk.

心理的負荷における筋弾性と自律神経機能への影響

The purpose of this study was to clarify the following: (1) effect on the elasticity of the musculus trapezius caused by psychological load, and (2) relationship between psychological load, muscle elasticity, and the autonomic nervous system (ANS) by frequency analysis of heart rate variability. The experiment was conducted on a group of 30 healthy volunteers, consisting of 16 males and 14 females with an average age of 31.2 years old. We investigated and compared the changes in muscle elasticity and ANS in the case of control (resting), phonating and mental calculation as psychological load. Psychological status and stress response were measured by using State-Trate Anxiety Inventory (STAI), Stress Checklist (SCL), and Stress Tolerance Checklist (STCL). As a result, the subjects experienced effective acute emotional stress during mental calculation, and muscle elasticity increased significantly. Heart rate (HR), low frequency (LF) component, and LF/HF increased significantly during mental calculations. The high frequency (HF) component tended to decrease during mental calculations. The rate of elevation of muscle elasticity and HR (difference between at rest and when calculating) was significantly related to STAI and STCL. STCL was significantly related to state of anxiety. The results of this study suggest that anxiety and stress tolerance affect muscle elasticity.

Autonomic Nervous System Changes During Reiki Treatment: A Preliminary Study

to investigate if a complementary therapy, Reiki, has any effect on indices of autonomic nervous system function. Blind trial. Quiet room in an out-patient clinic. Forty-five (45) subjects assigned at random into three groups. Three treatment conditions: no treatment (rest only); Reiki treatment by experienced Reiki practitioner; and placebo treatment by a person with no knowledge of Reiki and who mimicked the Reiki treatment. Quantitative measures of autonomic nervous system function such as heart rate, cardiac vagal tone, blood pressure, cardiac sensitivity to baroreflex, and breathing activity were recorded continuously for each heartbeat. Values during and after the treatment period were compared with baseline data. Heart rate and diastolic blood pressure decreased significantly in the Reiki group compared to both placebo and control groups. The study indicates that Reiki has some effect on the autonomic nervous system. However, this was a pilot study with relatively few subjects and the changes were relatively small. The results justify further, larger studies to look at the biological effects of Reiki treatment.

Loss of Efferent Vagal Activity in Acute Schizophrenia

Abstract An increased heart rate has been reported in schizophrenia. It is unclear whether this is due to disease-related autonomic nervous system changes or a side effect of antipsychotic medication. Altered cardiac autonomic function might to some extent account for the elevated cardiovascular mortality rate of schizophrenic patients. We assessed heart rate variability (HRV) in 30 acute unmedicated schizophrenic patients and matched controls. Patients were re-investigated 2–4 days after initiation of treatment to assess effects of medication. Our study demonstrates that non-medicated schizophrenic patients were significantly different in heart rate (increase) and parasympathetic parameters (loss of efferent vagal activity) at rest and during deep respiration. No significant effect was found after initiation of neuroleptic therapy. We found a correlation between duration of disease and parasympathetic parameters as well as very low frequency power (VLF) and delusion (SAPS subscale). These data suggest that schizophrenia is accompanied by a loss of vagal efferent activity, probably due to disturbed cortical–subcortical circuits modulating the autonomic nervous system in acute psychosis. The definite mechanisms by which vagal activity might be suppressed in schizophrenia are unknown. Parasympathetic hypoactivity might increase the risk for sudden cardiac death and arrhythmias in this disease. Future studies are warranted to investigate the interaction between cardiac autonomic function and schizophrenia and to identify patients on risk.

Electrodiagnostic approaches: Establishing the Relation Between Heart Rate, Pain Intensity and Unpleasantness

The current clinical guidelines in rehabilitation convey clinicians to use heart rate (HR) measurements to quantify the physical limitations related to pain perception in certain types of functional evaluations. The rational under this practice is that pain elicits autonomic nervous system changes, therefore obtaining HR information may help in quantifying pain. However, it is not clearly establish if a painful stimulus will elicit a clinically significant HR response. The goal of this study is to verify the relation between HR and pain perception. Thirty-nine healthy subjects (20 women, 19 men) participated in this experimental study. A painful stimuli was induced by a 2 minutes hot water (47°C) immersion of the hand. HR was recorded before and during the stimulation at 15 seconds intervals. Mean HR was established for each interval and matched to VAS score. There was a significant intra-subject correlation between HR and pain intensity (r=0.50, p<.001) and unpleasantness (r = 0.55, p<.001). The correlation with unpleasantness subsisted after controlling for changes in pain intensity (partial correlation: r=.26, p<.001), but the partial correlation with intensity was not significant after controlling for unpleasantness (r=-0.06, p=0.29). Notably, HR changes were only weakly related to pain reports across individuals (intensity: r=0.18, unpleasantness: r=0.17), furthermore there was a strong gender effect. Men presented a strong correlation between mean HR and mean pain perception (intensity: r=0.64, unpleasantness: r=0.77) while this relation was absent in women (intensity: r=0.15, unpleasantness: r=0.08). Results show that for healthy volunteers, experimental pain can elicit a rise in HR up to 11% and is particularly related to the affective component of pain perception when intra-individual changes are considered. Moreover, the relation between HR response and pain are gender related. Clinical implications need to be further evaluated with patients before clinicians can use HR to assess pain.

Early Target Organ Damage and Its Reversibility: The Heart

Left ventricular hypertrophy (LVH) represents not only an adaptation to increased load, but also a risk factor and a marker of risk of cardiovascular diseases. It may be detected early in the development of the disease by electrocardiography or echocardiography. LVH is often associated to abnormalities of systolic and diastolic function, and its presence clearly predisposes not only to cardiac ischemia and to congestive heart failure, but also to a higher incidence of stroke. A large number of clinical and experimental studies have shown that long‐term antihypertensive treatment may be associated with regression of LVH. Long‐term antihypertensive treatment is associated with a progressive decrease of LV mass. Differences on reduction of LV mass using different classes of antihypertensive drugs for the same decrease of blood pressure are usually mild, although the effect on cardiac structure and tissue composition are probably not the same. In fact, not only the quantity of left ventricular mass, but also its quality (i.e., collagen content, contractile machinery) should be evaluated and improved by treatment. The incidence of cardiovascular events in hypertensive patients is clearly related to the value of LV mass achieved during treatment; in fact, a reduction in LVH by antihypertensive treatment is associated with improvement in outcome and with decrease of the risk of cardiovascular morbidity and mortality, even independently from changes of other risk factors, including blood pressure. In patients with LVH at baseline, the decrease of LV mass is associated with a number of pathophysiological changes such as 1) improved systolic performance at the midwall, 2) possible improvement of diastolic filling, 3) autonomic nervous system changes toward normalization, 4) possible reduction or ventricular arrhythmias and 5) coronary reserve improvement. All these changes might explain an improvement of clinical prognosis in hypertensive patients. Ongoing studies will more precisely assess the quantitative relation between development or regression of LV mass, improvement of systolic and diastolic function and incidence of cardiovascular events. At present time detection, prevention and reversal of LVH represent a major goal in the management of hypertensive patients.

NPR-C receptors are involved in C-type natriuretic peptide response on bile secretion

C-type natriuretic peptide (CNP) is a member of the natriuretic peptide family. Previous studies reported the presence of natriuretic peptide receptors and mRNA CNP in the liver. In the present work, we sought to establish the role of CNP in the regulation of bile secretion in the rat and the possible pathways involved. CNP diminished basal as well as bile salt-evoked bile flow and bile acid output in a dose-dependent manner. It also reduced the excretion of sodium, chloride, and potassium but did not modify bile pH or the excretion of phospholipids, total proteins, and glutathione. Neither parasympathetic nor sympathetic blockade abolished CNP inhibitory response on bile secretion. The selective NPR-C agonist, C-ANP-(4-23) amide, diminished bile flow and the co-administration of both peptides did not further decrease it. CNP did not alter mean arterial pressure or portal venous pressure at any given doses. CNP decreased bile acid-dependent flow without affecting bile acid-independent flow. The inhibitory effect of CNP did not involve the participation of the autonomic nervous system or hemodynamic changes. The participation of NPR-C receptors in CNP response is strongly supported by present findings. The present study shows that CNP modulates bile secretion in the rat, suggesting that CNP may be part of the large family of peptides involved in the regulation of gastrointestinal physiology.

Depersonalization Again Finds Psychiatric Spotlight

Depersonalization Again Finds Psychiatric Spotlight

Perioperative atrial tachyarrhythmias.

Perioperative atrial tachyarrhythmias.

Heart rate variability and autonomic nervous system changes in children with vasovagal syncope.

The aim of this study was to evaluate the HRV at rest and during tilt test (HUTT) in children with a history of vasovagal syncope and to link the HRV indices with the clinical results of the test. HRV indices were assessed in the supine position and during the initial 5 minutes of the 60-degree HUTT in 49 patients (33 females, 16 males, mean age of 13 +/- 2.8 years) who were evaluated for recurrent syncope. The positive to negative results of the test were 21 to 28. The normalized power of high frequency component (npHF) decreased, normalized power of low frequency component (npLF) and the LF:HF ratio increased during HUTT of tilt-positive patients (P < 0.05 for each parameter). Parallel changes, but to a lesser degree, were observed for similar HRV parameters of tilt-negative patients. In addition, the HF and all the time-domain indices decreased significantly (P < or = 0.05) during HUTT in the latter group. When the tilt-positive and -negative patients were compared, the npHF was lower (P = 0.002), npLF and LF:HF ratio were higher (P = 0.01 and P = 0.001, respectively) during the test in tilt-positive patients, reflecting increased sympathetic tone in this group. A cut-off point for LF:HF was assigned as 2.7 for differentiating tilt-negative and tilt-positive results. The specificity, sensitivity, and positive and negative predictive values of this cut-off point were calculated as 93%, 52%, 85%, and 41%, respectively. Patients with vasovagal syncope show variations in vagal autonomic tone and appear to be more prone to syncope when their sympathetic tone is elevated at the beginning of the test. LF:HF > 2.7 is a specific marker (specificity 93%) and can correctly predict a positive tilt test in 85% of patients.

Effects of combining midazolam and barbiturate on the response to tracheal intubation: changes in autonomic nervous system

Study Objective: To investigate the effects on the autonomic nervous system of anesthesia induction with a combination of midazolam and barbiturate using plasma catecholamine concentration and heart rate (HR) variability in comparison with the induction with barbiturate alone. Design: Prospective study. Setting: Operating room of a university hospital. Patients: 40 ASA physical status I and II patients aged 30 to 70 years, who were scheduled for general anesthesia. Interventions: Anesthesia was induced with 0.1 mg/kg midazolam followed by 3 mg/kg thiopental sodium (Midazolam-Barbiturate group) or thiopental 5 mg/kg (Barbiturate group) with 6 L/min oxygen. Measurements: Arterial blood pressure (BP), HR, HR variability, and plasma concentrations of epinephrine and norepinephrine were measured. Main Results: Blood pressure and HR increased in response to tracheal intubation in both groups, but the increase was significantly larger in the Barbiturate group. In the Barbiturate group, the high-frequency component (HF) in HR variability increased significantly during intubation, whereas in the Midazolam-Barbiturate group, HF decreased continuously. The low-frequency component (LF)/HF ratio increased in both groups, with significantly higher values noted in the Barbiturate group. Plasma epinephrine concentrations decreased before intubation and increased in response to tracheal intubation in the Barbiturate group. Finally, plasma norepinephrine concentrations increased in response to tracheal intubation only in the Barbiturate group. Conclusions: Anesthesia induction with a combination of midazolam-thiopental was effective in reducing hemodynamic and cardiac autonomic nervous system responses to tracheal intubation in comparison with the conventional induction with thiopental alone.

The association between personal measurements of environmental exposure to particulates and heart rate variability.

Epidemiologic evidence indicates that airborne particulates are associated with mortality risk, predominately from heart disease. This may occur through changes in the cardiac autonomic nervous system, witnessed by changes in heart rate variability. This short-term longitudinal study used continuous personal particulate matter measurements to examine the effects of exposure to particulate matter less than 2.5 microm in diameter (PM2.5) on heart rate and rate variability in 20 relatively young, healthy male workers. Continuous exposure and cardiac monitoring were performed on each subject on a nonwork day. The 5-minute standard deviation of the normal-to-normal interval was used as the main measure of heart rate variability. Mixed-effects regression models estimate an average 1.4% (95% confidence limits = -2.1, -0.6) decrease in the 5-minute standard deviation of the normal-to-normal interval for each 100 microg/m3 increase in the 3-hour PM2.5 moving average, and small increases in heart rate, after adjustment for potential confounding factors. Predicted effects of exposure were greatest using the 3-hour averaging interval for PM2.5 and decreased in magnitude using shorter and longer intervals. These results reveal an association between cardiac autonomic function and environmental PM2.5 exposure. These observed associations may result from decreased vagal or increased sympathetic tone.

Heart rate variability and arterial blood pressure variability show different characteristic changes during hemorrhage in isoflurane-anesthetized, mechanically ventilated dogs.

We assessed the changes in heart rate variability (HRV) and blood pressure variability (BPV) as indices of autonomic nervous system and volume status during hemorrhage in isoflurane-anesthetized, mechanically ventilated dogs. Nine dogs were used. They were sequentially subjected to withdrawal of 30% estimated blood volume and graded isoflurane inhalation of 1% and 2% followed by discontinuation of isoflurane and retransfusion. The power spectra of HRV and BPV were computed using the fast Fourier transformation, and were quantified by determining the areas of the spectrum in two component widths: low-frequency component (LF) (0.04-0.15 Hz) and high-frequency component (HF) (0.15-0.4 Hz). During hemorrhage and isoflurane anesthesia, both HRV-LF and HRV-HF were decreased and plateaued at the smaller concentration of isoflurane, whereas BPV-LF decreased concentration-dependently. BPV-HF showed a completely different response and increased significantly during 2% isoflurane. We speculate that HRV and BPV-LF would be affected by the autonomic nervous activity, whereas BPV-HF would depend on relative/absolute change in circulating blood volume. Power spectra of heart rate variability (HRV) and blood pressure variability (BPV) were computed using the fast Fourier transformation. The HRV and BPV showed their differential characteristics during hemorrhage, isoflurane anesthesia, and retransfusion, and would help to assess changes in autonomic nervous system and preload under mechanical ventilation.

Schlaf und vegetative Systeme

Physiological changes of autonomic nervous system occur during non-rapid-eye-movement (NREM) and rapid-eye-movement (REM) sleep. This changes include typical variations in the respiratory or cardiovascular system respiratory rate, heart rate, heart rate variability, blood pressure), electrodermal activity, sexual functiions, thermoregulation, pupillomotoric and cerebral blood flow. Description and explanation of changes of all these autonomic functions in different sleep-stages permit understanding of pathophysiology of many neurological discorders or disturbances of sleep. In every chapter there are examples of patients with autonomic dysfunction in sleep as sleep-apnea-syndrome, stroke, Parkinson's syndrome or multiple system atrophy (MSA).