Relaxation-induced EEG alterations in panic disorder patients

Effect of brief mindfulness and relaxation inductions on anxiety, affect and brain activation in athletes

The mindfulness-based intervention and psychological skills training are often used for maintaining the mental health or reducing undesirable mental states in athletes. However, their differences in acute effects on mental health and underlying neural mechanism are not well understood. Therefore, the purpose of the current study was to examine the differential effects of brief mindfulness induction (MI) and relaxation induction (RI) on state anxiety, affect and brain activation. Thirty-five track and field athletes were recruited for this study. Using a within-subjects crossover design, participants underwent three conditions that incorporated two 30-min experimental conditions (i.e., MI or RI) and a control condition. State anxiety and affect were assessed before and after intervention, and brain activation (i.e., theta, alpha bands) were recorded by electroencephalography (EEG) during each 30-min condition. Repeated measures analysis of variance revealed that MI and RI similarly reduced state anxiety and negative affect from pre-test to post-test compared to the control condition. In terms of positive affect, there were no significant differences among the three conditions across times. Furthermore, participants exhibited higher frontal theta power during the MI and RI than control condition, whereas no differences in alpha power were observed among conditions. The current study provides initial evidence from an electrophysiological perspective that brief MI and RI both improve the negative psychological states in individual sport athletes through similar neural mechanisms. Nevertheless, the moderating effects of training experiences and long-term interventions on mental state and EEG activity in athletes need further investigation in future studies.

Relaxation Degree Analysis Using Frontal Electroencephalogram Under Virtual Reality Relaxation Scenes

Increasing social pressure enhances the psychological burden on individuals, and the severity of depression can no longer be ignored. The characteristics of high immersion and interactivity enhance virtual reality (VR) application in psychological therapy. Many studies have verified the effectiveness of VR relaxation therapy, although a few have performed a quantitative study on relaxation state (R-state). To confirm the effectiveness of VR relaxation and quantitatively assess relaxation, this study confirmed the effectiveness of the VR sightseeing relaxation scenes using subjective emotion scale and objective electroencephalogram (EEG) data from college students. Moreover, some EEG features with significant consistent differences after they watched the VR scenes were detected including the energy ratio of the alpha wave, gamma wave, and differential asymmetry. An R-state regression model was then built using the model stacking method for optimization, of which random forest regression, AdaBoost, gradient boosting (GB), and light GB were adopted as the first level, while linear regression and support vector machine were applied at the second level. The leave-one-subject-out method for cross-validation was used to evaluate the results, where the mean accuracy of the framework achieved 81.46%. The significantly changed features and the R-state model with over 80% accuracy have laid a foundation for further research on relaxation interaction systems. Moreover, the VR relaxation therapy was applied to the clinical treatment of patients with depression and achieved preliminary good results, which might provide a possible method for non-drug treatment of patients with depression.

EEG Correlates of Cognitive Functions and Neuropsychiatric Disorders: A Review of Oscillatory Activity and Neural Synchrony Abnormalities

Background:

A large body of evidence suggested that disruption of neural rhythms and synchronization of brain oscillations are correlated with a variety of cognitive and perceptual processes. Cognitive deficits are common features of psychiatric disorders that complicate treatment of the motivational, affective and emotional symptoms.

Objective:

Electrophysiological correlates of cognitive functions will contribute to understanding of neural circuits controlling cognition, the causes of their perturbation in psychiatric disorders and developing novel targets for the treatment of cognitive impairments.

Methods:

This review includes a description of brain oscillations in Alzheimer’s disease, bipolar disorder, attention-deficit/hyperactivity disorder, major depression, obsessive compulsive disorders, anxiety disorders, schizophrenia and autism.

Results:

The review clearly shows that the reviewed neuropsychiatric diseases are associated with fundamental changes in both spectral power and coherence of EEG oscillations.

Conclusion:

In this article, we examined the nature of brain oscillations, the association of brain rhythms with cognitive functions and the relationship between EEG oscillations and neuropsychiatric diseases. Accordingly, EEG oscillations can most likely be used as biomarkers in psychiatric disorders.

Characterization of EEG patterns in brain-injured subjects and controls after a Snoezelen(®) intervention

BACKGROUND AND OBJECTIVE

The aim of this study was to assess the changes induced in electroencephalographic (EEG) activity by a Snoezelen(®) intervention on individuals with brain-injury and control subjects.

METHODS

EEG activity was recorded preceding and following a Snoezelen(®) session in 18 people with cerebral palsy (CP), 18 subjects who have sustained traumatic brain-injury (TBI) and 18 controls. EEG data were analyzed by means of spectral and nonlinear measures: median frequency (MF), individual alpha frequency (IAF), sample entropy (SampEn) and Lempel-Ziv complexity (LZC).

RESULTS

Our results showed decreased values for MF, IAF, SampEn and LZC as a consequence of the therapy. The main changes between pre-stimulation and post-stimulation conditions were found in occipital and parietal brain areas. Additionally, these changes are more widespread in controls than in brain-injured subjects, which can be due to cognitive deficits in TBI and CP groups.

CONCLUSIONS

Our findings support the notion that Snoezelen(®) therapy affects central nervous system, inducing a slowing of oscillatory activity, as well as a decrease of EEG complexity and irregularity. These alterations seem to be related with higher levels of relaxation of the participants.

Alpha oscillations and their impairment in affective and post-traumatic stress disorders

Affective and anxiety disorders are debilitating conditions characterized by impairments in cognitive and social functioning. Elucidating their neural underpinnings may assist in improving diagnosis and developing targeted interventions. Neural oscillations are fundamental for brain functioning. Specifically, oscillations in the alpha frequency range (alpha rhythms) are prevalent in the awake, conscious brain and play an important role in supporting perceptual, cognitive, and social processes. We review studies utilizing various alpha power measurements to assess abnormalities in brain functioning in affective and anxiety disorders as well as obsessive compulsive and post-traumatic stress disorders. Despite some inconsistencies, studies demonstrate associations between aberrant alpha patterns and these disorders both in response to specific cognitive and emotional tasks and during a resting state. We conclude by discussing methodological considerations and future directions, and underscore the need for much further research on the role of alpha functionality in social contexts. As social dysfunction accompanies most psychiatric conditions, research on alpha's involvement in social processes may provide a unique window into the neural mechanisms underlying these disorders.

Electroencephalographic findings in panic disorder

Some studies have reported the importance of electroencephalography (EEG) as a method for investigating abnormal parameters in psychiatric disorders. Different findings in time and frequency domain analysis with regard to central nervous system arousal during acute panic states have already been obtained. This study aimed to systematically review the EEG findings in panic disorder (PD), discuss them having a currently accepted neuroanatomical hypothesis for this pathology as a basis, and identify limitations in the selected studies. Literature search was conducted in the databases PubMed and ISI Web of Knowledge, using the keywords electroencephalography and panic disorder; 16 articles were selected. Despite the inconsistency of EEG findings in PD, the major conclusions about the absolute power of alpha and beta bands point to a decreased alpha power, while beta power tends to increase. Different asymmetry patterns were found between studies. Coherence studies pointed to a lower degree of inter-hemispheric functional connectivity at the frontal region and intra-hemispheric at the bilateral temporal region. Studies on possible related events showed changes in memory processing in PD patients when exposed to aversive stimuli. It was noticed that most findings reflect the current neurobiological hypothesis of PD, where inhibitory deficits of the prefrontal cortex related to the modulation of amygdala activity, and the subsequent activation of subcortical regions, may be responsible to trigger anxiety responses. We approached some important issues that need to be considered in further researches, especially the use of different methods for analyzing EEG signals.

Effects of a multi-sensory environment on brain-injured patients: assessment of spectral patterns

Snoezelen(®) multi-sensory (SMS) environment has been commonly applied as a therapeutic strategy to alleviate the symptoms associated to a wide variety of pathologies. Despite most studies have reported a wide range of positive revealed short-term changes associated to SMS intervention, little has been done to systematically quantify its effects. The present study examined electroencephalographic (EEG) changes in 18 individuals with brain-injury and 18 healthy controls during SMS stimulation. The experimental design included a multi-sensory stimulation session carried out in a Snoezelen(®) room, preceded and followed by a 5 min quiet rest condition. Spontaneous EEG activity was analyzed by computing the relative power in conventional EEG frequency bands. The results suggest that SMS stimulation induces a significant increase (p < 0.05, Wilcoxon sign-ranked test) of relative power for low frequency bands (i.e., theta and alpha bands) and a significant decrease (p < 0.05, Wilcoxon sign-ranked test) for fast rhythms (i.e., beta1, beta2 and gamma bands). In addition, statistically significant differences (p < 0.05, Mann-Whitney U-test) between both groups were found in relative power of theta band. Our findings suggest that the slowing of EEG oscillatory activity may reflect the state of relaxation induced by the SMS stimulation. Furthermore, this study presents a new strategy to assess the short-term effects of SMS stimulation therapy in comparison to previous studies using subjective observations and qualitative data.

Muscle relaxation therapy for anxiety disorders: it works but how?

Muscle relaxation therapy (MRT) has continued to play an important role in the modern treatment of anxiety disorders. Abbreviations of the original progressive MRT protocol [Jacobson, E. (1938). Progressive relaxation (2nd ed.). Chicago: University of Chicago Press] have been found to be effective in panic disorder (PD) and generalized anxiety disorder (GAD). This review describes the most common MRT techniques, summarizes recent evidence of their effectiveness in treating anxiety, and explains their rationale and physiological basis. We conclude that although GAD and PD patients may exhibit elevated muscle tension and abnormal autonomic and respiratory measures during laboratory baseline assessments, the available evidence does not allow us to conclude that physiological activation decreases over the course of MRT in GAD and PD patients, even when patients report becoming less anxious. Better-designed studies will be required to identify the mechanisms of MRT and to advance clinical practice.

EEG mapping in patients with social phobia

Recent studies have suggested an information-processing bias in social phobia (SP). Little is known about the electrophysiological correlates of anxiety in SP. The aim of the present study was to investigate the quantitative electroencephalogram (EEG) in 25 drug-free patients with SP as compared with age- and sex-matched normal controls and to correlate anxiety and depressive symptoms with EEG data. EEG was recorded under vigilance-controlled and resting conditions. The Spielberger State and Trait Anxiety Scale (STAI) and the Beck Depression Inventory (BDI) were administered to assess anxiety and depression levels. Multivariate analysis of variance revealed significant differences between patients and controls, specifically frontopolarly and right centrally. Statistical analysis demonstrated a decrease in absolute and relative delta, theta power, alpha-adjacent slow-beta and fast beta power and an increase in absolute and relative intermediate beta power, as well as an acceleration of the total centroid and a slowing in beta centroid and its variability. Trait anxiety and depression scores correlated positively with the dominant alpha frequency and the alpha centroid, and negatively with absolute theta and slow alpha power as well as with the centroid of the delta/theta frequency band. In conclusion, EEG mapping in patients with SP revealed significant differences from normal controls suggesting a hyperarousal as a pathogenetic factor of anxiety.

Effect of the 5-HT(1A) partial agonist buspirone on regional brain electrical activity in man: a functional neuroimaging study using low-resolution electromagnetic tomography (LORETA)

In a double-blind, placebo-controlled study, the effects of 20 mg buspirone - a 5-HT(1A) partial agonist - on regional electrical generators within the human brain were investigated utilizing three-dimensional EEG tomography. Nineteen-channel vigilance-controlled EEG recordings were carried out in 20 healthy subjects before and 1, 2, 4, 6 and 8 h after drug intake. Low-resolution electromagnetic tomography (LORETA; Key Institute for Brain-Mind Research, software: http://www.keyinst.unizh.ch) was computed from spectrally analyzed EEG data, and differences between drug- and placebo-induced changes were displayed as statistical parametric maps. Data were registered to the Talairach-Tournoux human brain atlas available as a digitized MRI (McConnell Brain Imaging Centre: http://www.bic.mni.mcgill.ca). At the pharmacodynamic peak (1st hour), buspirone increased theta and decreased fast alpha and beta sources. Areas of theta increase were mainly the left temporo-occipito-parietal and left prefrontal cortices, which is consistent with PET studies on buspirone-induced decreases in regional cerebral blood flow and fenfluramine-induced serotonin activation demonstrated by changes in regional cerebral glucose metabolism. In later hours (8th hour) with lower buspirone plasma levels, delta, theta, slow alpha and fast beta decreased, predominantly in the prefrontal and anterior limbic lobe. Whereas the results of the 1st hour speak for a slight CNS sedation (more in the sense of relaxation), those obtained in the 8th hour indicate activation. Thus, LORETA may provide useful and direct information on drug-induced changes in central nervous system function in man.