Frontal Alpha Asymmetry in Children with Trauma Exposure.

The purpose of the current study was to investigate differences in frontal alpha asymmetry (FAA) between children (5-17 years) with or without histories of trauma exposure. EEG data were obtained from 165 children who participated in the Healthy Brain Network Initiative during rest with eyes open and closed. FAA during resting-state electroencephalography was significantly more negative in the trauma-exposed group, suggesting greater left lateralized FAA and avoidance-oriented motivation. Moreover, alpha suppression (difference in alpha amplitude between eyes open and eyes closed conditions) was marginally greater in the trauma-exposed group. The results suggest that early exposure to trauma may be associated with trait-level avoidance of environmental stimuli, which ultimately may be predictive of psychopathology, including posttraumatic stress disorder (PTSD). Study findings thus provide preliminary evidence of brain-based mechanisms that may confer risk for PTSD in the wake of early trauma exposure.

Evaluating the empirical evidence for three transdiagnostic mechanisms in anxiety and mood disorders.

High co-morbidity among mental disorders indicates that common transdiagnostic mechanisms underlie various psychopathology, yet there has been little research effort to empirically explicate transdiagnostic processes. A few existing studies are limited in the number of transdiagnostic mechanisms and mental disorder categories explored. The current study addresses these limitations by examining the relationship between three transdiagnostic processes (experiential avoidance, rumination, and emotion dysregulation) and symptom severity of five mental disorders (generalized anxiety disorder, panic disorder, social anxiety disorder, specific phobia, and depression) in a college sample (N = 266). Applying Structural Equation Modeling (SEM), three transdiagnostic models were evaluated, with the five latent variables of mental disorder regressed onto each transdiagnostic process. The results showed that all transdiagnostic models-except the emotion dysregulation model-generally fit the data well. Among the tested models, the strongest evidence was found for experiential avoidance as a transdiagnostic mechanism underlying multiple disorders, suggesting the need for further research effort to reduce experiential avoidance in diverse clinical populations.

Effects of a Brief Mindfulness-Based Attentional Intervention on Threat-Related Perceptual Decision-Making.

OBJECTIVES: Threat-related cues and contexts facilitate perceptual decision-making, yet it is unclear whether this threat-driven tuning of perceptual decision-making is modifiable by top-down attentional control. Since state and dispositional mindfulness are linked to improved attentional control, we examined whether these factors assist the use of prior knowledge to detect threatening stimuli. METHODS: Participants were randomly assigned to a brief mindfulness-based intervention (N=32) or a physics lecture audio recording (N=31) and then asked to perform a task in which they used threatening and neutral cues to discriminate between threatening and neutral faces. RESULTS: Results showed that threatening cues led to faster and more sensitive perceptual decision-making, specifically for threatening faces. Furthermore, higher levels of dispositional mindfulness were associated with improved ability to use cues to discriminate between threatening and neutral stimuli in the group that underwent a brief mindfulness induction but not in the control group. CONCLUSIONS: Our findings highlight how top-down attention-related dispositions and strategies can influence our ability to detect threats in our environment.

Does mindfulness-based intervention improve cognitive function?: A meta-analysis of controlled studies.

Theoretical accounts and preliminary evidence suggest that Mindfulness-Based Interventions (MBIs) improve cognitive function, but reviews of empirical studies have provided mixed results. To clarify empirical evidence, we conducted a meta-analysis of 25 studies (n = 1439) and examined the effects of MBIs on four cognitive domains: attention, working memory, long-term memory, and executive function. The summary effect sizes indicate that MBIs produce non-significant effects on attention (SMD = 0.07), working memory (SMD = 0.16), and long-term memory (SMD = -0.12), while a small effect was observed for executive function (SMD = 0.29). Given significant heterogeneity across studies, we conducted meta-regression analyses with sample characteristics, age, number of treatment sessions, treatment duration, intervention type, control group type, and study design. We found moderating effects of intervention type on attention and executive function. Although the current study highlights preliminary evidence for improvements in executive function, overall results suggest non-significant findings for attention, working memory, and long-term memory. To draw a firm conclusion, further research is needed to address methodological challenges in meta-analysis and the limitations of existing studies.

A Systematic Review of Mindfulness-Based Interventions for Patients with Mild Cognitive Impairment or Dementia and Caregivers.

The aim of this article was to systematically review the quality and efficacy of the current evidence for mindfulness-based interventions (MBIs) in patients with mild cognitive impairment (MCI), patients with dementia (PwD), and their caregivers. We identified 20 randomized controlled trials (RCTs) (11 for patients, 9 for caregivers) published in the last 15 years. Evidence suggested that MBIs are highly acceptable and credible treatments for patients with MCI, PwD and caregivers. Specifically, for PwD, the results indicated that the magnitude of post-treatment effects of MBIs are in the medium to large range for psychosocial outcomes, and in the small to medium range for cognitive functioning; however, treatment effects on dementia biomarkers were mixed, ranging from small to large, depending on the outcome measure. Findings also evidenced salutary effects of MBIs for caregivers of PwD, with post-treatment effects ranging from medium to large for caregiver stress and burden and large effects for quality of life, and mixed outcomes for cognitive functioning, with effects in the small to large range. However, confidence in these findings is relatively limited due to methodological limitations, especially in terms of poor consistency in intervention strategies, outcome measures, and other key criteria across studies. To better assess the value of MBIs for these populations and optimize treatment outcomes, we recommend further research with improved study methodology (e.g., multi-method assessment, universal criterion and outcome measures, use of active control groups, larger sample sizes, long-term follow-up) to replicate current findings and enhance our understanding of underlying treatment mechanisms of MBIs.

Disrupted Control Network Connectivity in Abstinent Patients with Alcohol Dependence.

OBJECTIVE: Alcohol causes damage to the brain and is associated with various functional impairments. However, much of the brain damage can be reversed by abstaining for enough time. This study aims to investigate the patterns and degrees of brain function in abstinent patients with alcohol dependence by using resting-state functional connectivity. METHODS: 26 male patients with alcohol dependence (alcohol group) and 28 age-matched male healthy volunteers (control group) were recruited from a mental hospital and the community, respectively. Using 3T MRI scan data, the resting-state functional connectivity of the task-negative and task-positive networks was determined and compared between the groups. RESULTS: There were no significant group differences in the resting-state functional connectivity in the default mode or in the salience and sensorimotor networks. Compared with the control group, the alcohol group showed significantly lower functional connectivity in the executive control network, especially in the cingulo-opercular network and, in some regions of interest, the dorsal attention network. CONCLUSION: This finding suggests that some brain networks do not normalize their functions after abstinence from drinking, and these results may be helpful in future research to investigate the mechanisms for craving alcohol and alcohol relapse prevention.

Volume of hippocampal subfields in patients with alcohol dependence.

Alcohol-induced hippocampal atrophy has been well documented in many studies and is known to affect various subfields. Given the functional heterogeneity of these subfields, we investigated the precise effects of alcohol-induced damage in these areas. Twenty-six male patients with alcohol dependence (alcohol group) and twenty-six age-matched male healthy social drinkers were recruited from a mental health hospital and the community respectively, with the aim of comparing the hippocampal subfields between groups. Each participant underwent a 3T MRI scan. Hippocampal subfield volumes were estimated using an automated procedure and drinking history recorded using Lifetime Drinking History, Alcohol Use Disorder Identification Test, and the Brief Michigan Alcoholism Screening Test. The alcohol group showed a lower total hippocampus volume, specifically in the left presubiculum, fimbria, and bilateral subiculum. Regression analysis assessing the influence of age and group showed that group was a more significant factor than age in most subfields. Our findings suggest that alcohol dependence alters hippocampal subfield volumes. Further longitudinal studies on the interaction of structural and neurocognitive changes would improve our understanding of brain structural changes resulting from long-term alcohol consumption.

Surface-Based Parameters of Brain Imaging in Male Patients with Alcohol Use Disorder.

OBJECTIVE: The structural alteration of brain shown in patients with alcohol use disorder (AUD) can originate from both alcohol effects and genetic or developmental processes. We compared surface-based parameters of patients with AUD with healthy controls to prove the applicability of surface-based morphometry with head size correction and to determine the areas that were sensitive to brain alteration related to AUD. METHODS: Twenty-six abstinent male patients with AUD (alcohol group, mean abstinence=13.2 months) and twenty-eight age-matched healthy participants (control group) were recruited from an inpatient mental hospital and community. All participants underwent a 3T MRI scan. Surface-based parameters were determined by using FreeSurfer. RESULTS: Every surface-based parameter of the alcohol group was lower than the corresponding control group parameter. There were large group differences in the whole brain, grey and white matter volume, and the differences were more prominent after head size correction. Significant group differences were shown in cortical thicknesses in entire brain regions, especially in parietal, temporal and frontal areas. There were no significant group differences in surface areas, but group difference trends in surface areas of the frontal and parietal cortices were shown after head size correction. CONCLUSION: Most of the surface-based parameters in alcohol group were altered because of incomplete recovery from chronic alcohol exposure and possibly genetic or developmental factors underlying the risk of AUD. Surface-based morphometry with controlling for head size is useful in comparing the volumetric parameters and the surface area to a lesser extent in alcohol-related brain alteration.