[Impaired daytime functions in children with sleep disorders].

Sleep in adequate amount and quality is essential for normal child development. Sleep disorders may affect the childs daytime functions resulting in behavioral problems such as attention deficit, aggressiveness and hyperactivity. Recent reports have suggested that chronic sleep disturbance can cause neurocognitive deficits and impaired learning abilities. Obstructive sleep apnea syndrome, asthma, atopic dermatitis and juvenile rheumatoid arthritis--are common childhood diseases that can impair normal sleep. This article reviews the sleep characteristics in these diseases and the relation between sleep quality and the social and intellectual performance of the child during the day.

Phasic heart period reactions to cued threat and nonthreat stimuli in generalized anxiety disorder.

The hallmark of generalized anxiety disorder (GAD) is chronic uncontrollable worry. A preattentive bias toward threat cues and hypervigilance may support this ongoing state of apprehension. A study was conducted to bridge the attentional and physiological underpinnings of GAD by examining phasic heart period (HP) responses to cued threat and nonthreat stimuli. Thirty-three GAD clients and 33 nonanxious control participants engaged in an S1-S2 procedure that employed cued threat and nonthreat word stimuli, during which phasic HP reactions were recorded. As compared with the control group, the GAD group showed (1) smaller cardiac orienting responses and impaired habituation of cardiac orienting to neutral words, (2) HR acceleration in response to threat words, and (3) a conditioned anticipatory HR deceleration to threat words over repeated trials. The cardiac-autonomic underpinnings of GAD appear to rigidly maintain precognitive defensive responses against threat. This portrayal is discussed in the context of an integrative model that depicts diminished global adaptive variability in GAD.

Anxiety and autonomic flexibility: a cardiovascular approach.

Autonomic characteristics of panickers, blood phobics, and nonanxious controls were compared with a variety of cardiovascular measures, including spectral analysis of the cardiac inter-beat interval time series (derived from the electrocardiogram). Responses to laboratory stressors (shock avoidance and cold face stress) of 16 participants who reported recent occurrences of frequent severe panic attacks, 15 participants who reported strong somatic reactions and fainting to the sight of blood, and 15 controls, were recorded. Results suggested distinct autonomic patterns among the three groups. Across conditions, panickers displayed the highest heart rates (HR) coupled with the least HR variability, which indicates low levels of cardiac vagal tone. Blood phobics showed more vagally mediated HR variability than panickers, with a significant association between cardiac rate and mean arterial pressure. Controls generally showed the most HR variability and 'spectral reserve' (a quality that indicates flexible responsivity). Results are discussed in the context of traditional models of anxiety and autonomic activity in contrast to contemporary notions of stability and change in biological systems.

Heart period variability and depressive symptoms: gender differences.

BACKGROUND: Deceased heart period variability has been associated with cardiac events and depressive symptoms; however, the results of studies are not unequivocal. We hypothesize that gender differences in the various study samples may have contributed to the lack of uniformity of findings. METHODS: Time and frequency domain measures of heart period variability during a 5-min resting baseline were examined in 15 depressed (8 female) and 11 nondepressed (6 female) college students. RESULTS: Both time and frequency domain measures indicated an interaction between gender and depressive symptoms, such that depressed male subjects showed less heart period variability, whereas depressed female subjects showed more heart period variability compared to their nondepressed counterparts. CONCLUSIONS: These results suggest that future studies investigating the relationship between heart period variability and depressive symptoms examine gender differences.

Anxiety and autonomic flexibility: a cardiovascular approach.

Autonomic characteristics of panickers, blood phobics, and nonanxious controls were compared with a variety of cardiovascular measures, including spectral analysis of the cardiac inter-beat interval time series (derived from the electrocardiogram). Responses to laboratory stressors (shock avoidance and cold face stress) of 16 participants who reported recent occurrences of frequent severe panic attacks, 15 participants who reported strong somatic reactions and fainting to the sight of blood, and 15 controls, were recorded. Results suggested distinct autonomic patterns among the three groups. Across conditions, panickers displayed the highest heart rates (HR) coupled with the least HR variability, which indicates low levels of cardiac vagal tone. Blood phobics showed more vagally mediated HR variability than panickers, with a significant association between cardiac rate and mean arterial pressure. Controls generally showed the most HR variability and 'spectral reserve' (a quality that indicates flexible responsivity). Results are discussed in the context of traditional models of anxiety and autonomic activity in contrast to contemporary notions of stability and change in biological systems.

The effect of autonomic nervous system activity on gastric myoelectrical activity: does the spectral reserve hypothesis hold for the stomach?

Previous studies have associated changes in gastric myoelectrical activity during motion sickness, as indexed using the electrogastrogram (EGG), with changes in autonomic nervous system (ANS) activity. Subjects who did not report nausea in a rotating optokinetic drum were characterized by normal 3 cycles per minute (cpm) gastric myoelectrical activity, strong parasympathetic nervous system (PNS) activity, and low sympathetic nervous system (SNS) activity. The goals of this study were: (1) to determine whether tasks previously shown to alter ANS activity as indexed by changes in cardiac inter-beat intervals (IBIs) would result in systematic changes in gastric myoelectrical activity in accord with the findings from motion sickness studies; and (2) to determine whether the 'spectral reserve hypothesis' applies to gastric myoelectrical activity. EGGs and IBIs were collected from 24 healthy subjects during resting/baseline, reaction time/shock-avoidance (RT) and cold face stress (CF) tasks. Tachyarrhythmia was found to be significantly greater during the RT task than during the baseline and CF tasks. It was concluded that: (1) tasks that alter ANS activity do systematically alter gastric myoelectrical activity; and (2) gastric myoelectrical activity does not follow the cardiac model of health being associated with increased spectral complexity.

Autonomic balance revisited: panic anxiety and heart rate variability.

The analysis of heart rate variability (HRV) is becoming widely used in clinical research to provide a window into autonomic control of HR. This technique has been valuable in elucidating the autonomic underpinnings of panic disorder (PD), a condition that is marked by reports of heart palpitations. A body of research has emerged that implicates a relative reduction in HRV and cardiac vagal tone in PD, as indicated by various HRV measures. These data are consistent with the cardiac symptoms of panic attacks, as well as with developmental evidence that links high vagal tone with enhanced attention, effective emotion regulation, and organismic responsivity. Implications of these findings for nosology and pathophysiology are discussed. Reports of reduced HRV in PD contrast with portrayals of excess autonomic lability in anxiety. This contradiction is addressed in the context of traditional homeostatic models versus a systems perspective that views physiologic variability as essential to overall stability.

Spectral characteristics of heart period variability during cold face stress and shock avoidance in normal subjects.

Spectral analysis of heart period variability was used to examine autonomic cardiac control in several tasks used in experimental and clinical assessments of autonomic nervous system function. Cardiovascular measures were recorded in healthy humans during quiet rest, reaction time shock-avoidance, cold face stress, and combined shock-avoidance/cold face stress. Shock-avoidance was characterized by sympathetic beta-adrenergic dominance, as evidenced by (1) shorter heart periods, (2) less high-frequency spectral power, (3) elevated low-frequency power, (4) increased ratios of low- to high-frequency power, and (5) a steep regression line fitted to the log-log plot of the power spectra. Cold face stress yielded (1) longer heart periods, (2) more high-frequency power, (3) decreased low-frequency spectral power, and (4) a flat regression slope, indicating vagal dominance. Quiet rest appeared as mildly vagal, with less total spectral power, and the combination task elicited a mixed vagal-sympathetic pattern. These results are discussed in the context of (1) the autonomic underpinnings of low-frequency power, (2) the autonomic effects of facial cooling, and (3) the utility of spectral analysis of heart period variability during autonomic challenge tasks for basic research and clinical application.

Autonomic characteristics of generalized anxiety disorder and worry.

Autonomic characteristics of generalized anxiety disorder (GAD) and worry were examined using measures of heart period variability. The cardiorespiratory responses of 34 GAD clients and 32 nonanxious control subjects were recorded during resting baseline, relaxation, and worry periods. Results indicated differences between GAD subjects and controls as well as among baseline, relaxation, and worry periods. GAD clients exhibited shorter cardiac interbeat intervals (IBIs) and lower high frequency spectral power across all task conditions. Relative to baseline and relaxation conditions, worry was associated with (1) shorter IBIs, (2) smaller mean successive differences (MSD) of the cardiac IBIs, and (3) lower high frequency spectral power. These findings suggest that GAD and its cardinal feature (worry), are associated with lower cardiac vagal control. The findings of the present study provide evidence for the utility of further exploration of the role of autonomic nervous system activity in GAD.

A behavioral link between the oculomotor and cardiovascular systems.

Although the eyes and the heart serve very different purposes, each receives autonomic innervation. Capitalizing on recent theoretical and technological innovations in the understanding and assessment of oculomotor and cardiovascular behavior, three experiments measured behavioral covariation between the oculomotor and cardiovascular systems. Measures of dark focus and dark vergence indexed oculomotor tone, and the spectral decomposition of variations in heart rate indexed cardiovascular control mechanisms. In Experiment 1, individual differences in cardiovascular parameters could predict individuals' dark vergence (R2 = .806) but not their dark focus (R2 = .404). In Experiment 2, the same parameters were measured from subjects who experience either panic attacks (n = 11) or blood phobia (n = 9). Heart rate was positively correlated with dark vergence and the two subject groups were separable based on both oculomotor and cardiovascular variables. Using a within-subjects approach, Experiment 3 found that both dark vergence and dark focus tended to be nearer during sympathetic dominance of the heart than during parasympathetic dominance, within-subjects variations in cardiovascular parameters could predict dark focus, and between-subjects variations in interbeat intervals could predict dark vergence. Shared patterns of autonomic activation may be responsible for this eye-heart link.

Autonomic characteristics of nonclinical panic and blood phobia.

Autonomic characteristics of nonclinical panic and blood phobia were compared using spectral analysis of the electrocardiogram (EKG), as well as more conventional cardiovascular measures. The cardiovascular responses of 11 subjects who reported recent occurrence of frequent severe panic attacks, and 10 subjects who reported intense somatic reactions to the sight of blood (including episodes of syncope) were recorded during a variety of laboratory tasks (quiet rest, reaction time/shock avoidance, face immersion, and combined reaction time/face immersion). Results suggest distinct autonomic patterns in the groups. Panickers showed (a) higher heart rate and reduced heart-rate variability (b) aberrant associations among cardiovascular measures, and (c) dominant sympathetic control of heart rate coupled with diminished vagal tone. Blood phobics generally displayed an opposite pattern. The relevance of these findings to the etiology of panic and blood phobia, as well as to biological models of anxiety disorders in general, is discussed.

Facial muscle activity and EEG recordings: redundancy analysis.

The present study explored the use of redundancy analysis, a multivariate technique for assessment of interset association, to examine facial muscle contamination of EEG recordings in studies involving covert levels of emotional expression. Redundancy analyses were performed on simultaneously recorded EEG and facial EMG data obtained in an emotion induction paradigm. Redundancy indices obtained suggest that (1) the amount of variance in EEG activity that can be explained by facial muscle activity under such conditions is minimal, and (2) the EEG alpha band may be at least as or even more susceptible to muscle contamination as the beta band.

The selection of an amputation level with radioactive microspheres.

The results of studies in progress will provide data concerning radioactivity per unit area over various sites on the extremity to determine the relative perfusions between amputation sites.These quantitative data, when combined with the qualitative interpretation and correlated retrospectively with the clinical course of the amputee, should enhance the ability to predict the healing potential.

Peripheral vascular perfusion scanning. Correlation with the arteriogram and clinical assessment in the patient with peripheral vascular disease.

Peripheral vascular perfusion scan during rest and reactive hyperemia does not necessarily offer the same information as the arteriogram or the clinical assessment of the peripheral pulses. The information obtained from the peripheral vascular perfusion scan offers potentially clinically useful information regarding the physiologic significance of various arterial lesions to the surgeon in selection of his therapeutic approach. The peripheral vascular perfusion scan uniquely and under varied physiologic conditions permits assessment of the effect of arterial disease on the distribution of perfusion within the extremity. The peripheral vascular perfusion scan is not in competition with, but is complementary to, arteriography and clinical assessment of the patient with peripheral vascular disease.