Autonomic Changes (autonomic + change)

Distribution by Scientific Domains


Selected Abstracts


The ontogeny of autonomic measures in 6- and 12-month-old infants

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2006
Abbey Alkon
Abstract The purpose of this study was to develop a standardized protocol to measure preejection period (PEP), a measure of sympathetic nervous system, and respiratory sinus arrhythmia (RSA), a measure of parasympathetic nervous system, during resting and challenging states for 6- and 12-month-old infants and to determine developmental changes and individual stability of these measures. A 7-min reactivity protocol was administered to Latino infants at 6 months (n,=,194) and 12 months (n,=,181). Results showed: (1) it is feasible to measure PEP and RSA in infants, (2) the protocol elicited significant autonomic changes, (3) individual resting autonomic measures were moderately stable from 6 to 12 months, but reactivity measures were not stable, and (4) heart rate and RSA resting and challenge group means changed significantly from 6 to 12 months. Findings suggest that although infants' autonomic responses show developmental changes, individuals' rank order is stable from 6 to 12 months of age. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 197,208, 2006. [source]


Cardiac Dysrhythmia Associated with the Immediate Postictal State after Maximal Electroshock in Freely Moving Rat

EPILEPSIA, Issue 4 2002
Olivier Darbin
Summary: ,Purpose: Cardiac autonomic changes accompany complex partial seizures and generalized tonic,clonic seizures, and participate, at least partially, in the sudden and unexpected death in epilepsy (SUDEP). The analysis of the heart rate variability (HRV) is one of the simplest ways of providing insight into autonomic functions. The entropy quantifies the repetition of complex patterns in a signal and refers to systems randomness, regularity, and predictability. Clinical investigations have reported that entropy decreases in patients with a high risk of sudden cardiac death. The goal of this study was to evaluate the effects of the maximal electroshock (MES) on the entropy of HRV, monitored in the immediate postictal stage in the model of the freely moving rat. Methods: Entropy changes were correlated with the high and low frequencies of spectral analysis, which reflect the participation of the sympathetic and parasympathetic activities. Results: MES-induced arrhythmia is characterized by an HRV increase, an imbalance in favor of the parasympathetic activity, and a decrease in the entropy. Entropy decrease was restricted to the duration of the arrhythmia, suggesting that the postictal arrhythmia may be associated with a higher risk of lethal cardiac complications. Nevertheless, entropy changes did not correlate with spectral changes. Conclusions: The results suggest that the imbalance demonstrated in the spectral domain explains only partially the contribution of each autonomic system in the complexity of the heart rate during the postictal state. [source]


Heart Rate Variability and Sympathetic Skin Response in Male Patients Suffering From Acute Alcohol Withdrawal Syndrome

ALCOHOLISM, Issue 9 2006
Karl-Jürgen Bär
Background: Many symptoms of alcohol withdrawal (AW) such as tachycardia or elevated blood pressure might be explained by increased peripheral and central adrenergic activity. In contrast to many neurochemical studies of sympathetic activation during AW, only very few studies investigated autonomic balance using neurophysiological methods. Methods: We investigated heart rate variability (HRV) and sympathetic skin response (SSR) in male patients suffering from mild AW syndrome (n=20, no treatment required) and in patients with moderate to severe AW syndrome (n=20, clomethiazole treatment) in the acute stage. Sympathovagal influence was quantified using measures of time and frequency domain of HRV as well as modern nonlinear parameters (compression entropy). Furthermore, we obtained latencies and amplitudes of SSR to quantify isolated sympathetic influence. Measures were obtained during the climax of withdrawal symptomatology before treatment, 1 day after climax, and shortly before discharge from hospital. Alcohol withdrawal scores were obtained and correlated to autonomic measures. Results: Ambulatory blood pressure and AW scores revealed characteristic withdrawal symptoms in both patient groups. Apart from the nonlinear parameter compression entropy, Hc, measures of HRV revealed no sign of autonomic dysfunction in contrast to the significantly increased heart rates at the time of admission. Latencies and amplitudes of SSR did not indicate any increase of sympathetic activity. A negative correlation was found between Hc and mental withdrawal symptoms. Conclusions: We show here that classical measures for autonomic nervous system activity such as HRV and SSR are not suitable for describing the autonomic changes seen in acute AW, although a major role for the sympathetic nervous system has been proposed. This might be due to multiple dysregulation of metabolites in AWS or to subtle alcohol-induced damage to neuronal structures, issues that should be addressed in future studies. [source]


Psychophysiological reactivity in female sexual abuse survivors

JOURNAL OF TRAUMATIC STRESS, Issue 4 2001
Annmarie McDonagh-Coyle
Abstract This study examined psychophysiological reactivity in 37 female childhood sexual abuse (CSA) survivors. After assessment of posttraumatic stress disorder (PTSD), psychiatric comorbidity, and trauma history, we conducted a psychophysiological assessment of forehead muscle tension, electrodermal activity, and heart rate during a mental arithmetic task and 4 script-driven imagery tasks (neutral, consensual sex, pleasant, and trauma). PTSD symptom severity correlated positively with psychophysiologic changes and negative emotions during the trauma imagery task. During mental arithmetic, PTSD symptom severity correlated negatively with autonomic changes and positively with negative emotions. These results extend earlier PTSD research showing trauma-specific increased psychophysiological reactivity related to CSA in women with PTSD. They further suggest a negative association between PTSD severity and autonomic reactions to mental arithmetic. [source]


Heart Rate Variability in Obstructive Sleep Apnea: A Prospective Study and Frequency Domain Analysis

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2003
Lorne J Gula F.R.C.P.C.
Background: Cyclic variation of the heart rate is observed during apneic spells in obstructive sleep apnea (OSA). We hypothesized that autonomic changes would affect frequency-domain measures of heart rate variability (HRV). Methods: We studied 20 patients (15 men, 5 women, mean age 47.2 ± 12.2 years) with suspected OSA undergoing overnight polysomnography, and five patients (4 men, 1 woman, mean age 49.2 ± 8.6 years) with recently diagnosed sleep apnea undergoing polysomnography while wearing continuous positive airway pressure (CPAP). Holter monitors were applied during sleep studies and data were analyzed in 5-minute blocks over the course of the night. Using spectral analysis, low frequency (LF) and high frequency (HF) powers were calculated for each interval. Overall mean and standard deviation (SD) for LF power, HF power, and the LF:HF ratio were recorded for each patient. Comparisons were made between patients with severe OSA (apnea hypopnea index (AHI) > 30, n = 8), moderate OSA (AHI 1,30, n = 5), without OSA (AHI < 10, n = 7), and patients wearing CPAP (n = 5). Results: Assessment of overnight LF or HF power revealed no significant difference between the four groups. The LF:HF ratio, which represents sympathovagal balance, was higher among those with moderate disease compared to normals and those with severe OSA (both P = 0.037). The standard deviation of the LF:HF ratio was higher among those with moderate disease compared to normals (P = 0.0064) and those with severe OSA (P = 0.0006). OSA patients receiving CPAP behaved like patients with moderate OSA, with increased SD of the LF:HF ratio. Conclusions: The observed changes in the LF:HF ratio and its SD suggest an increased sympathetic tone and discordance in sympathovagal activity in moderate OSA, which is blunted in severe OSA. CPAP may restore autonomic defects, characteristic of severe OSA, to moderate levels. [source]


Haemodynamic changes after spinal cord transection are anaesthetic agent dependent

AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 4 2007
P. R. Leal
Summary 1 To evaluate the effect of high spinal cord transection (SCT), between T4 and T5, on the mean arterial pressure (MAP) and heart rate in animals anaesthetized with different anaesthetic agents: ether (n = 12), 20% urethane, 1.2 g kg,1 (n = 12), 2% tri-bromide-ethanol, 200 mg kg,1 (n = 12); chloral hydrate and urethane, 75 and 525 mg kg,1 respectively (n = 12). 2 In the animals anaesthetized with ether or urethane, SCT caused an immediate major drop in MAP, with hypotension and bradycardia throughout the next 10 min. In the animals anaesthetized with urethane + chloralose or tri-bromide-ethanol, SCT transiently increased MAP with subsequent hypotension and bradycardia. 3 In summary, the haemodynamic changes after complete, high SCT are anaesthetic agent dependent. Further research about the exact mechanisms responsible for these diverse autonomic changes is warranted. [source]