Integrative assessment of brain and cognitive function in post-traumatic stress disorder

Auditory N2 Correlates of Treatment Response in Posttraumatic Stress Disorder

Emotional processing and cognitive control are implicated as being dysfunctional in posttraumatic stress disorder (PTSD) and targeted in cognitive processing therapy (CPT), a trauma-focused treatment for PTSD. The N2 event-related potential has been interpreted in the context of emotional processing and cognitive control. In this analysis of secondary outcome measures from a randomized controlled trial, we investigated the latency and amplitude changes of the N2 in responses to task-relevant target tones and task-irrelevant distractor sounds (e.g., a trauma-related gunshot and a trauma-unrelated lion's roar) and the associations between these responses and PTSD symptom changes. United States military veterans (N = 60) diagnosed with combat-related PTSD were randomized to either active or sham repetitive transcranial magnetic stimulation (rTMS) and received a CPT intervention that included a written trauma account element (CPT+A). Participants were tested before and 6 months after protocol completion. Reduction in N2 amplitude to the gunshot stimulus was correlated with reductions in reexperiencing, |r| = .445, and hyperarousal measures, |r| = .364. In addition, in both groups, the latency of the N2 event-related potential to the distractors became longer with treatment and the N2 latency to the task-relevant stimulus became shorter, η_p ²  = .064, both of which are consistent with improved cognitive control. There were no between-group differences in N2 amplitude and latency. Normalized N2 latencies, reduced N2 amplitude to threatening distractors, and the correlation between N2 amplitude reduction and PTSD symptom reduction reflect improved cognitive control, consistent with the CPT+A objective of addressing patients' abilities to respond more appropriately to trauma triggers.

Baseline cortisol predicts drunkorexia in female but not male college students

"Drunkorexia" or compensatory eating behaviors in response to alcohol consumption, resembles a subclinical eating disorder, and is a current public health concern. Eating disorders and alcohol abuse are associated with dysfunction of the hypothalamic-pituitary-adrenal axis (HPA). One index of HPA function is cortisol. As causes of drunkorexia remain elusive, the present study examined cortisol function as it relates to drunkorexia. Participants:n = 73 (49 women) college students. Method: Participants provided daytime saliva samples for cortisol analyses prior to completing an online survey measuring alcohol consumption, drunkorexia, and alcohol problems as measured by the Rutgers Alcohol Problem Index (RAPI). Results: Multiple regressions indicated that baseline cortisol significantly positively correlated with drunkorexia behaviors in women but not men. Higher baseline cortisol and aspects of drunkorexia related to alcohol problems. Conclusion: Programs educating about stress management and health risks of drunkorexia may decrease engagement in drunkorexia behaviors among college students.

Event related potentials indexing the influence of emotion on cognitive processing in veterans with comorbid post-traumatic stress disorder and traumatic brain injury

OBJECTIVE

Emotion regulation and cognitive executive control are significantly impaired in both post-traumatic stress disorder (PTSD) and traumatic brain injury (TBI). These illnesses are increasingly common in veterans and their co-occurrence may exacerbate symptoms and recovery. The current study sought to investigate neural correlates of these impairments via event-related potentials (ERPs) and examined the association of PTSD symptom severity and impulsivity with these correlates.

METHODS

Electroencephalographic data from seventy-nine veterans with PTSD and TBI and 17 control participants were recorded during a visual emotional oddball task and analyzed for the N2 and P3b ERPs.

RESULTS

Results revealed that veterans showed a reduced P3b ERP in response to both target images and standard images. However, for standard images that followed a negative emotional distractor, the veterans showed a heightened N2 amplitude while the controls did not. In addition, impulsivity predicted modulation of the P3b across stimulus conditions, with a greater P3b amplitude associated with an increase in impulsivity.

CONCLUSIONS

These findings suggest that veterans showed hyper-responsivity to background information and reduced ERPs to task-relevant information.

SIGNIFICANCE

These findings may reflect heightened internal states that create neural noise and a reduced ability to modulate relevant responses.

The impact of posttraumatic stress disorder on event-related potentials in affective and non-affective paradigms: A systematic review with meta-analysis

Post-traumatic stress disorder (PTSD) is associated with neural processing deficits affecting early automatic and later conscious processing. Event-related Potentials (ERPs) are high resolution indices of automatic and conscious processing, but there are no meta-analyses that have examined automatic and conscious ERPs in PTSD across multiple paradigms. This systematic review examined 69 studies across affective and non-affective auditory and visual paradigms. Individuals with PTSD were compared to trauma-exposed and non-trauma controls on ERPs reflecting automatic (N1, P1, N2, P2) and conscious (P3, LPP) processing. Trauma exposure was associated with increased automatic ERP amplitudes to irrelevant auditory information. PTSD further showed increased automatic and conscious allocation of resources to affective information, reduced automatic attending and classification as well as reduced attention processing and working memory updating of non-affective information. Therefore, trauma exposure is associated with enhanced early processing of incoming stimuli, and PTSD with enhanced processing of affective stimuli and impaired processing of non-affective stimuli. This review highlights the need for longitudinal ERP studies in PTSD, adopting standardized procedures and methodological designs.

Evaluation of Neurofeedback for Posttraumatic Stress Disorder Related to Refugee Experiences Using Self-Report and Cognitive ERP Measures

Background. Neurofeedback holds promise as an intervention for the psychophysiological dysfunction found in posttraumatic stress disorder (PTSD). Few empirical studies have assessed the efficacy of neurofeedback for PTSD, and none in individuals with refugee trauma. A proposed mechanism for neurofeedback efficacy in PTSD is through remediating deficits in cognitive control. We assessed pre- and postchanges in symptoms and neurocognitive functioning of refugee clients participating in a neurofeedback intervention for PTSD. Methods. Clinical data for 13 adult refugees with chronic PTSD who participated in neurofeedback combined with trauma counseling (NFT) was compared with 13 adult refugees placed on a waitlist to receive neurofeedback. Waitlist clients continued to receive trauma counseling alone (TC). NFT was additionally assessed pre- and posttherapy for changes in event-related potentials (ERPs) and behavioral indices of cognitive control using a visual continuous performance task (VCPT). Comparison VCPT data from healthy controls (HC) was available from the Human Brain Index database. Results. Posttherapy, NFT had significantly lower symptoms of trauma, anxiety, and depression compared with TC. NFT demonstrated an increased P3 amplitude and improved behavioral performance suggesting a normalization of cognitive control. Conclusions. These preliminary observations are consistent with a possible benefit of neurofeedback for remediating PTSD. This may be achieved at least partially by an improvement in cognitive control. Further confirmation of the effectiveness of the treatment now requires a randomized controlled trial that considers issues such as placebo response, nonspecific therapist effects, and duration of treatment.

Effects of 8 weeks of modified hatha yoga training on resting-state brain activity and the p300 ERP in patients with physical disability-related stress

[Purpose] We examined the effects of Hatha yoga on EEG and ERP in patients with physical disability-related stress. [Participants and Methods] Eighteen male and female injured workers with high stress levels, aged between 18 to 55 years, were evenly divided into two groups: untrained (CG) and trained (TG) modified hatha yoga groups. A modified Hatha yoga protocol was designed for this population by two certified yoga instructors, approved by a physical therapist, and conducted for one hour, three times weekly for 8 weeks. [Results] The results indicated a significant increase in alpha EEG activity over the frontal, central, and parietal electrodes and the delta EEG activity over the centroparietal electrode from pre- to post-training in TG. In addition, significantly faster auditory reaction time for target stimuli, as well as lower P300 peak latency of ERP in auditory oddball paradigm were obtained in TG after 8 weeks of yoga training compare to CG. [Conclusion] Changes in brain activity and ERP components following yoga training would support the psychophysiological effects of hatha yoga as an adjunct to routine rehabilitation.

Neural responses to emotional involuntary memories in posttraumatic stress disorder: Differences in timing and activity

Background

Involuntary memories are a hallmark symptom of posttraumatic stress disorder (PTSD), but studies of the neural basis of involuntary memory retrieval in posttraumatic stress disorder (PTSD) are sparse. The study of the neural correlates of involuntary memories of stressful events in PTSD focuses on the voluntary retrieval of memories that are sometimes recalled as intrusive involuntary memories, not on involuntary retrieval while being scanned. Involuntary memory retrieval in controls has been shown to elicit activity in the parahippocampal gyrus, precuneus, inferior parietal cortex, and posterior midline regions. However, it is unknown whether involuntary memories are supported by the same mechanisms in PTSD. Because previous work has shown that both behavioral and neural responsivity is slowed in PTSD, we examined the spatiotemporal dynamics of the neural activity underlying negative and neutral involuntary memory retrieval.

Methods

Twenty-one individuals with PTSD and 21 non-PTSD, trauma-exposed controls performed an involuntary memory task, while undergoing a functional magnetic resonance imaging scan. Environmental sounds served as cues for well-associated pictures of negative and neutral scenes. We used a finite impulse response model to analyze temporal differences between groups in neural responses.

Results

Compared with controls, participants with PTSD reported more involuntary memories, which were more emotional and more vivid, but which activated a similar network of regions. However, compared to controls, individuals with PTSD showed delayed neural responsivity in this network and increased vmPFC/ACC activity for negative > neutral stimuli.

Conclusions

The similarity between PTSD and controls in neural substrates underlying involuntary memories suggests that, unlike voluntary memories, involuntary memories elicit similar activity in regions critical for memory retrieval. Further, the delayed neural responsivity for involuntary memories in PTSD suggests that factors affecting cognition in PTSD, like increased fatigue, or avoidance behaviors could do so by delaying activity in regions necessary for cognitive processing. Finally, compared to neutral memories, negative involuntary memories elicit hyperactivity in the vmPFC, whereas the vmPFC is typically shown to be hypoactive in PTSD during voluntary memory retrieval. These patterns suggest that considering both the temporal dynamics of cognitive processes as well as involuntary cognitive processes would improve existing neurobiological models of PTSD.

Attentional processes in posttraumatic stress disorder and the associated changes in neural functioning

Posttraumatic Stress Disorder (PTSD) is associated with alterations in attention at the behavioral and neural levels. However, there are conflicting findings regarding the specific type of attention impairments present in PTSD, as the commonly used tests of attention do not isolate the mechanisms behind attention abnormalities, and the constructs measured do not map onto the neurocircuits governing attention. Here, we review the literature on attention processing in PTSD and offer directions for future research to clarify these unanswered questions. First, using instruments that allow assessment of behavioral and neurophysiological attention components will be necessary to understand attention deficits in PTSD. Second, focus on intra-individual variability in addition to assessment of central tendency may help clarify some of the mixed findings. Third, longitudinal studies on attentional processes are warranted to determine how attention contributes to the development and maintenance of PTSD. Integration of behavioral and neural measures of attention will be useful in understanding the pathophysiology of PTSD.

Moment to moment variability in functional brain networks during cognitive activity in EEG data

Functional brain networks (FBNs) are gaining increasing attention in computational neuroscience due to their ability to reveal dynamic interdependencies between brain regions. The dynamics of such networks during cognitive activity between stimulus and response using multi-channel electroencephalogram (EEG), recorded from 16 healthy human participants are explored in this research. Successive EEG segments of 500[Formula: see text]ms duration starting from the onset of cognitive stimulation have been used to analyze and understand the cognitive dynamics. The approach employs a combination of signal processing techniques, nonlinear statistical measures and graph-theoretical analysis. The efficacy of this approach in detecting and tracking cognitive load induced changes in EEG data is clearly demonstrated using graph metrics. It is revealed that most cognitive activity occurs within approximately 500[Formula: see text]ms of the stimulus presentation in addition to temporal variability in the FBNs. It is shown that mutual information (MI), a nonlinear measure, produces good correlations between the EEG channels thus enabling the construction of FBNs which are sensitive to cognitive load induced changes in EEG. Analyses of the dynamics of FBNs and the visualization approach reveal hard to detect subtle changes in cognitive function and hence may lead to a better understanding of cognitive processing in the brain. The techniques exploited have the potential to detect human cognitive dysfunction (impairments).

EEG correlates of the severity of posttraumatic stress symptoms: A systematic review of the dimensional PTSD literature

BACKGROUND

Considering the Research Domain Criteria (RDoC) framework, it is crucial to investigate posttraumatic stress disorder (PTSD) as a spectrum that ranges from normal to pathological. This dimensional approach is especially important to aid early PTSD detection and to guide better treatment options. In recent years, electroencephalography (EEG) has been used to investigate PTSD; however, reviews regarding EEG data related to PTSD are lacking, especially considering the dimensional approach. This systematic review examined the literature regarding EEG alterations in trauma-exposed people with posttraumatic stress symptoms (PTSS) to identify putative EEG biomarkers of PTSS severity.

METHOD

A systematic review of EEG studies of trauma-exposed participants with PTSS that reported dimensional analyses (e.g., correlations or regressions) between PTSS and EEG measures was performed.

RESULTS

The literature search yielded 1178 references, of which 34 studies were eligible for inclusion. Despite variability among the reviewed studies, the PTSS severity was often associated with P2, P3-family event-related potentials (ERPs) and alpha rhythms.

LIMITATIONS

The search was limited to articles published in English; no information about non-published studies or studies reported in other languages was obtained. Another limitation was the heterogeneity of studies, which made meta-analysis challenging.

CONCLUSIONS

EEG provides promising candidates to act as biomarkers, although further studies are required to confirm the findings. Thus, EEG, in addition to being cheaper and easier to implement than other central techniques, has the potential to reveal biomarkers of PTSS severity.

Altered processing of visual emotional stimuli in posttraumatic stress disorder: an event-related potential study

Patients with posttraumatic stress disorder (PTSD) display abnormal emotional processing and bias towards emotional content. Most neurophysiological studies in PTSD found higher amplitudes of event-related potentials (ERPs) in response to trauma-related visual content. Here we aimed to characterize brain electrical activity in PTSD subjects in response to non-trauma-related emotion-laden pictures (positive, neutral and negative). A combined behavioral-ERP study was conducted in 14 severe PTSD patients and 14 controls. Response time in PTSD patients was slower compared with that in controls, irrespective to emotional valence. In both PTSD and controls, response time to negative pictures was slower compared with that to neutral or positive pictures. Upon ranking, both control and PTSD subjects similarly discriminated between pictures with different emotional valences. ERP analysis revealed three distinctive components (at ~300, ~600 and ~1000 ms post-stimulus onset) for emotional valence in control subjects. In contrast, PTSD patients displayed a similar brain response across all emotional categories, resembling the response of controls to negative stimuli. We interpret these findings as a brain-circuit response tendency towards negative overgeneralization in PTSD.

Working memory training with tDCS improves behavioral and neurophysiological symptoms in pilot group with post-traumatic stress disorder (PTSD) and with poor working memory

This pilot study investigated the feasibility of treating people suffering from both post-traumatic stress disorder (PTSD) and poor working memory by employing a combination of computerized working memory training and transcranial direct current stimulation (tDCS). After treatment, all four participants showed clinically significant improvements on a range of cognitive and emotional performance measures. Moreover, these improvements were accompanied by theoretically significant neurophysiological changes between pre- and post-treatment electroencephalographic (EEG) recordings. Specifically, the P3a component of participants' event related potentials (ERP) in response to novelty stimuli, characteristically abnormal in this clinical population, shifted significantly toward database norms. So, participants' initially slow alpha peak frequency (APF), theorized to underlie impaired cognitive processing abilities, also increased in both frequency and amplitude as a result of treatment. On the basis of these promising results, more extensive controlled studies are warranted.

A quantitative meta-analysis of neurocognitive functioning in posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) is associated with regional alterations in brain structure and function that are hypothesized to contribute to symptoms and cognitive deficits associated with the disorder. We present here the first systematic meta-analysis of neurocognitive outcomes associated with PTSD to examine a broad range of cognitive domains and describe the profile of cognitive deficits, as well as modifying clinical factors and study characteristics. This report is based on data from 60 studies totaling 4,108 participants, including 1,779 with PTSD, 1,446 trauma-exposed comparison participants, and 895 healthy comparison participants without trauma exposure. Effect-size estimates were calculated using a mixed-effects meta-analysis for 9 cognitive domains: attention/working memory, executive functions, verbal learning, verbal memory, visual learning, visual memory, language, speed of information processing, and visuospatial abilities. Analyses revealed significant neurocognitive effects associated with PTSD, although these ranged widely in magnitude, with the largest effect sizes in verbal learning (d = -.62), speed of information processing (d = -.59), attention/working memory (d = -.50), and verbal memory (d =-.46). Effect-size estimates were significantly larger in treatment-seeking than community samples and in studies that did not exclude participants with attention-deficit/hyperactivity disorder, and effect sizes were affected by between-group IQ discrepancies and the gender composition of the PTSD groups. Our findings indicate that consideration of neuropsychological functioning in attention, verbal memory, and speed of information processing may have important implications for the effective clinical management of persons with PTSD. Results are further discussed in the context of cognitive models of PTSD and the limitations of this literature.

Stroop-interference effect in post-traumatic stress disorder

To investigate the conflict processing in posttraumatic stress disorder (PTSD) patients, we conducted the classical Stroop task by recording event-related potentials. Although the reaction time was overall slower for PTSD patients than healthy age-matched control group, the Stroop-interference effect of reaction time did not differ between the two groups. Compared with normal controls, the interference effects of N 2 and N 450 components were larger and the interference effect of slow potential component disappeared in PTSD. These data indicated the dysfunction of conflict processing in individuals with PTSD.

Stress-related psychological symptoms are associated with increased attentional capture by visually salient distractors

Research has shown that attention can be abnormally drawn to salient threat- or trauma-related information in individuals with posttraumatic stress and related psychological symptoms. The nature of this attentional bias is thought to derive from capture of attention toward potential threat overpowering the volitional, goal-directed attentional system. However, it is unclear whether this pattern of attentional dysregulation generalizes to salient, but non-emotional types of information. Using a well-established and sensitive measure of attentional capture, the current study demonstrates that posttraumatic psychological symptom severity is associated with the capture of attention by visually salient, non-emotional distractors. Specifically, during visual search for a unique shape, the presence of a task-irrelevant but salient color singleton disrupted search efficiency, and this disruption was correlated with both posttraumatic stress disorder (PTSD) and depression symptom severity as assessed by self-report. These findings suggest that posttraumatic stress and depression may be characterized as involving a general alteration of the balance between salience-based and goal-directed attentional systems.

Peak high-frequency HRV and peak alpha frequency higher in PTSD

Posttraumatic stress disorder (PTSD) is difficult to treat and current PTSD treatments are not effective for all people. Despite limited evidence for its efficacy, some clinicians have implemented biofeedback for PTSD treatment. As a first step in constructing an effective biofeedback treatment program, we assessed respiration, electroencephalography (EEG) and heart rate variability (HRV) as potential biofeedback parameters for a future clinical trial. This cross-sectional study included 86 veterans; 59 with and 27 without PTSD. Data were collected on EEG measures, HRV, and respiration rate during an attentive resting state. Measures were analyzed to assess sensitivity to PTSD status and the relationship to PTSD symptoms. Peak alpha frequency was higher in the PTSD group (F(1,84) = 6.14, p = 0.01). Peak high-frequency HRV was lower in the PTSD group (F(2,78) = 26.5, p < 0.00005) when adjusting for respiration rate. All other EEG and HRV measures and respiration were not different between groups. Peak high-frequency HRV and peak alpha frequency are sensitive to PTSD status and may be potential biofeedback parameters for future PTSD clinical trials.

Adolescent suicide in Australia: rates, risk and resilience

Adolescent suicide rates in Australia have fallen significantly during recent years. The incidence, however, clearly remains a serious concern for young people, parents, professionals and policy makers. Some groups of Australian youth appear to be at heightened risk. Adolescents within the welfare system, indigenous, rural and refugee youth, along with same sex attracted young people often need very careful monitoring and support. Young men continue to take their lives more frequently than young women. Prevention programmes in Australia aim to develop resilience in young people, families and communities that can serve as protection against self harm and suicide. The improvement of mental health literacy, a fostering of adolescent self-efficacy and better access to early intervention strategies are currently privileged in national and state policies related to young people in Australia. More work is needed, however, to achieve a well integrated mental health framework capable of effectively addressing adolescent suicide prevention into the twenty-first century.

Meta-analytic review of P3 components in posttraumatic stress disorder and their clinical utility

Patients with posttraumatic stress disorder (PTSD) exhibiting disturbances in information processing, including trouble with attention, were studied. Event-related potentials (ERPs)-specifically, the P3 components (P3a, P3b, and P3 working memory {P3wm})-provide an objective, non-invasive, and cost-effective method for evaluating such disturbances. We evaluated the potential clinical utility of P3 components by examining the differences between PTSD and several control groups: normal participants, non-PTSD patients with trauma, and medicated patients with PTSD. We performed a meta-analysis of the ERP literature between 1990 and 2010 using a random effects model. P3a amplitude was larger in patients with PTSD compared to non-PTSD patients having trauma in the context of trauma-related distracters. P3b amplitude was also larger in patients with PTSD than in patients having trauma without PTSD, but in the context of trauma-related stimuli. P3b amplitude was smaller in patients with PTSD compared to normal controls in the context of neutral stimuli. P3wm signals were smaller with shorter latencies in patients with PTSD compared to normal controls or medicated patients with PTSD. The receiver-operator characteristic (ROC) analysis revealed that each P3 component had some potential to accurately classify patients, typically using amplitude for at least one lead. In conclusion, differences in P3 amplitude and latency between patients with PTSD and control patients confirm the results of Karl et al and extend our understanding of P3 as a neural correlate of working memory. These results further provide guidance on the potential design of future clinical trials supporting the development of P3 components as a PTSD diagnostic aid.

The relationship between Hippocampal asymmetry and working memory processing in combat-related PTSD - a monozygotic twin study

BACKGROUND

PTSD is associated with reduction in hippocampal volume and abnormalities in hippocampal function. Hippocampal asymmetry has received less attention, but potentially could indicate lateralised differences in vulnerability to trauma. The P300 event-related potential component reflects the immediate processing of significant environmental stimuli and has generators in several brain regions including the hippocampus. P300 amplitude is generally reduced in people with PTSD.

METHODS

Our study examined hippocampal volume asymmetry and the relationship between hippocampal asymmetry and P300 amplitude in male monozygotic twins discordant for Vietnam combat exposure. Lateralised hippocampal volume and P300 data were obtained from 70 male participants, of whom 12 had PTSD. We were able to compare (1) combat veterans with current PTSD; (2) their non-combat-exposed co-twins; (3) combat veterans without current PTSD and (4) their non-combat-exposed co-twins.

RESULTS

There were no significant differences between groups in hippocampal asymmetry. There were no group differences in performance of an auditory oddball target detection task or in P300 amplitude. There was a significant positive correlation between P300 amplitude and the magnitude of hippocampal asymmetry in participants with PTSD.

CONCLUSIONS

These findings suggest that greater hippocampal asymmetry in PTSD is associated with a need to allocate more attentional resources when processing significant environmental stimuli.

Mood symptoms contribute to working memory decrement in active-duty soldiers being treated for posttraumatic stress disorder

A significant proportion of military veterans of operations in Afghanistan and Iraq have been diagnosed with posttraumatic stress disorder (PTSD). Growing evidence suggests that neuropsychological deficits are a symptom of PTSD. The current study investigated neurocognitive functioning among soldiers diagnosed with PTSD. Specifically, active-duty soldiers with and without a diagnosis of PTSD were assessed for performance on tests of attention and working memory. In addition, factors such as combat experience, depression, anxiety, PTSD symptom severity, and alcohol consumption were explored as possible mediators of group differences in neurocognitive functioning. Twenty-three active-duty soldiers diagnosed with PTSD were matched with 23 healthy Soldier controls; all were administered the Attention Network Task (ANT), Backward Digit Span (BDS) task, Beck Depression Inventory, Beck Anxiety Inventory, PTSD Checklist-Military Version, Combat Exposure Scale, and Modified Drinking Behavior Questionnaire. Soldiers diagnosed with PTSD performed significantly worse on the working memory task (BDS) than healthy controls, and reported greater levels of PTSD symptoms, combat exposure, depression, and anxiety. However, after controlling for depression and anxiety symptoms, the relationship between PTSD and working memory was no longer present. The results indicate that PTSD is accompanied by deficits in working memory, which appear to be partially attributed to anxiety and depression symptoms.

Cognitive training for impaired neural systems in neuropsychiatric illness

Neuropsychiatric illnesses are associated with dysfunction in distributed prefrontal neural systems that underlie perception, cognition, social interactions, emotion regulation, and motivation. The high degree of learning-dependent plasticity in these networks-combined with the availability of advanced computerized technology-suggests that we should be able to engineer very specific training programs that drive meaningful and enduring improvements in impaired neural systems relevant to neuropsychiatric illness. However, cognitive training approaches for mental and addictive disorders must take into account possible inherent limitations in the underlying brain 'learning machinery' due to pathophysiology, must grapple with the presence of complex overlearned maladaptive patterns of neural functioning, and must find a way to ally with developmental and psychosocial factors that influence response to illness and to treatment. In this review, we briefly examine the current state of knowledge from studies of cognitive remediation in psychiatry and we highlight open questions. We then present a systems neuroscience rationale for successful cognitive training for neuropsychiatric illnesses, one that emphasizes the distributed nature of neural assemblies that support cognitive and affective processing, as well as their plasticity. It is based on the notion that, during successful learning, the brain represents the relevant perceptual and cognitive/affective inputs and action outputs with disproportionately larger and more coordinated populations of neurons that are distributed (and that are interacting) across multiple levels of processing and throughout multiple brain regions. This approach allows us to address limitations found in earlier research and to introduce important principles for the design and evaluation of the next generation of cognitive training for impaired neural systems. We summarize work to date using such neuroscience-informed methods and indicate some of the exciting future directions of this field.

Hydrocortisone reduces emotional distracter interference in working memory

Several studies have shown that stress and glucocorticoids can impair prefrontal-dependent working memory (WM) performance. WM is the ability to attend to the task at hand, and to maintain relevant information in mind during a delay while ignoring irrelevant stimuli. Here, it is investigated whether stress hormones impair WM by reducing the ability to suppress distracting, irrelevant neutral and emotional stimuli. Hydrocortisone (35 mg) (n=23) or placebo (n=21) was administered to young, healthy men, who performed a Sternberg WM task with neutral and emotional irrelevant distracters shown in the delay-phase of the task, between encoding and recognition of the relevant stimuli for WM. Contrary to expectations, enhanced WM performance with higher processing speed and a reduction of errors was found in the hydrocortisone group compared to placebo. Moreover, hydrocortisone significantly reduced the distraction by emotional stimuli. These findings show that cortisol effects on WM are not unambiguous and contrast with previous findings on the impairing effects of cortisol on WM. Dose-response studies could give more insight into the specific modulating effects of glucocorticoids on suppression of irrelevant emotional distraction.

Mild traumatic brain injury and posttraumatic stress disorder in returning veterans: perspectives from cognitive neuroscience

A significant proportion of military personnel deployed in support of Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) has been exposed to war-zone events potentially associated with traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD). There has been significant controversy regarding healthcare policy for those service members and military veterans who returned from OEF/OIF deployments with both mild TBI and PTSD. There is currently little empirical evidence available to address these controversies. This review uses a cognitive neuroscience framework to address the potential impact of mild TBI on the development, course, and clinical management of PTSD. The field would benefit from research efforts that take into consideration the potential differential impact of mild TBI with versus without persistent cognitive deficits, longitudinal work examining the trajectory of PTSD symptoms when index trauma events involve TBI, randomized clinical trials designed to examine the impact of mild TBI on response to existing PTSD treatment interventions, and development and examination of potential treatment augmentation strategies.

Developing an integrated brain, behavior and biological response profile in posttraumatic stress disorder (PTSD)

The present study sought to determine a profile of integrated behavioral, brain and autonomic alterations in PTSD. Previous findings suggest that PTSD is associated with changes across electrophysiological (EEG and ERP), autonomic and cognitive/behavioral measures. In particular, PTSD has been associated with reduced cognitive performance, altered cortical arousal (measured by EEG), diminished late ERP component to oddball task targets (reduced P3 amplitude) and increased autonomic arousal relative to healthy controls. The present study examined measures of cognitive function, auditory oddball ERP components, autonomic function (heart rate and skin conductance) and EEG during resting conditions in 44 individuals with PTSD and 44 non-trauma-exposed controls, and predicted that an integrated profile of changes across a number of these measures would show a high level of sensitivity and specificity in discriminating PTSD from controls. Nine variables showing strongly significant (p < 0.002) between-group differences were entered into a discriminant function analysis. Four of these measures successfully discriminated the PTSD and non-PTSD groups: change in tonic arousal, duration of attention switching, working memory reaction time and errors of commission during visuospatial maze learning. Tonic arousal change contributed the most variance in predicting group membership. These results extend previous findings and provide an integrated biomarker profile that characterizes both PTSD and non-PTSD groups with a high degree of sensitivity and specificity. This outcome provides a platform for future studies to test how this profile of disturbances in autonomic and information processing may be unique to PTSD or may occur generically across clinical and/or other anxiety disorders.

Evidence-based medicine evaluation of electrophysiological studies of the anxiety disorders

We provide a systematic, evidence-based medicine (EBM) review of the field of electrophysiology in the anxiety disorders. Presently, electrophysiological studies of anxiety focus primarily on etiological aspects of brain dysfunction. The review highlights many functional similarities across studies, but also identifies patterns that clearly differentiate disorder classifications. Such measures offer clinical utility as reliable and objective indicators of brain dysfunction in individuals and indicate potential as biomarkers for the improvement of diagnostic specificity and for informing treatment decisions and prognostic assessments. Common to most of the anxiety disorders is basal instability in cortical arousal, as reflected in measures of quantitative electroencephalography (qEEG). Resting electroencephalographic (EEG) measures tend to correlate with symptom sub-patterns and be exacerbated by condition-specific stimulation. Also common to most of the anxiety disorders are condition-specific difficulties with sensory gating and the allocation and deployment of attention. These are clearly evident from evoked potential (EP) and event-related potential (ERP) electrical measures of information processing in obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD), panic disorder (PD), generalized anxiety disorder (GAD) and the phobias. Other'ERP measures clearly differentiate the disorders. However, there is considerable variation across studies, with inclusion and exclusion criteria, medication status and control group selection not standardized within condition or across studies. Study numbers generally preclude analysis for confound removal or for the derivation of diagnostic biomarker patterns at this time. The current trend towards development of databases of brain and cognitive function is likely to obviate these difficulties. In particular, electrophysiological measures of function are likely to play a significant role in the development and subsequent adaptations of DSM-V and assist critically in securing improvements in nosological and treatment specificity.

Trauma and posttraumatic stress disorder in South African adolescents: a case-control study of cognitive deficits

Despite the prominence of neuropsychological deficits in memory, attention and learning in adults exposed to trauma and those who develop posttraumatic stress disorder (PTSD), few studies have explored these cognitive deficits in adolescents. This study aimed to assess the impact of PTSD on various neurocognitive functions in South African adolescents. In a case-control study, 40 traumatized adolescents (20 with PTSD and 20 without) were evaluated for the presence of PTSD and were then referred for neuropsychological evaluation using a standardized neuropsychological test battery. The presence of PTSD itself, rather than trauma exposure, was associated with cognitive deficiencies in attention, visual memory and nonverbal concept formation. This study highlights the impact of PTSD itself-and particularly current symptoms-on the cognitive development of adolescents. As this effect appears to be stronger than the impact of trauma alone, more studies on the long-term consequences of PTSD on youth cognitive development are crucial.

[Cognition and perception deficits in fibromyalgia and rheumatoid arthritis]

INTRODUCTION

Cognitive disturbance in patients with fibromyalgia and rheumatoid arthritis is today a topic of a great clinical interest, largely due to the fact that these persons often complain about cognitive problems.

OBJECTIVE

This study is aimed to assess the visuospatial memory, attention and perceptive capacities in chronic pain patients.

MATERIAL AND METHODS

Groups were constituted by fibromyalgia patients and rheumatoid arthritis patients, as well as a control group. All the subjects completed a battery of visual and spa-tial memory, speed of processing, working memory, attention, orientation and visuoperceptive abilities. A cognitive reserve measurement was obtained.

RESULTS

Results show that chronic pain patients displayed worse cognitive performance than controls. Moreover, arthritis patients execute poorly when compared to the group of fibromyalgia in tasks that demand visuoperceptive integration and visuomotor processing. Patients suffering fibromyalgia obtained worse punctuations than those with arthritis in spatial memory and spatial orientation tasks.

CONCLUSIONS

Both groups developed important cognitive deficits, which cannot be explained by the collateral effects of such pathologies, because cognitive profiles are not similar and appear from the beginning of the disease.

Consistent impaired verbal memory in PTSD: a meta-analysis

BACKGROUND

Qualitative review papers have indicated that verbal memory impairment is found to be the most consistent cognitive impairment related to PTSD. These review papers have used qualitative methods to describe the effects, and consequently they have not been able to estimate the strength of the memory-PTSD association.

METHODS

This meta-analysis of 28 studies examined the empirical evidence for this relationship, and factors affecting the results.

RESULTS

Overall, the results showed medium effect sizes in patients with PTSD compared to controls on verbal memory across studies. Marked impairment was found in the patient groups compared to healthy controls, while modest impairment was found compared to exposed non-PTSD controls. Meta-analyses found strongest effects in war veterans compared to sexual and physical assault related PTSD. Rather unexpectedly no effect was found for the sexually abused PTSD groups compared to exposed controls. The analyses further showed that the effect was dependent on the test procedures used. The studies using WMS and AVLT had stronger effects than studies using CVLT.

LIMITATIONS

Insufficient data were available to analyze a more complete attention-memory profile.

CONCLUSIONS

This meta-analysis confirms that verbal memory impairment is present in adults with PTSD, and they are consistent across studies. This impairment should be the focus of work in clinical settings.

Information Processing Bias in Post-traumatic Stress Disorder

This review considers theory and evidence for abnormal information processing in post-traumatic stress disorder (PTSD). Cognitive studies have indicated sensitivity in PTSD for traumatic information, more so than general emotional information. These findings were supported by neuroimaging studies that identify increased brain activity during traumatic cognition, especially in affective networks (including the amygdala, orbitofrontal and anterior cingulate cortex). In theory, it is proposed that traumatic cognition may interfere with neutral cognition and there is evidence of abnormal neutral stimulus processing in PTSD. Firstly, PTSD patients perform poorly on a variety of neuropsychology tasks that involve attention and memory for neutral information. The evidence from event-related potentials and functional neuroimaging also indicates abnormal results in PTSD during neutral stimulus processing. The research evidence generally provides support for theories of trauma sensitivity and abnormal neutral stimulus processing in PTSD. However, there is only tentative evidence that trauma cognition concurrently interferes with neutral cognition. There is even some evidence that traumatic or novelty arousal processes can increase the capacity for attentive processing, thereby enhancing cognition for neutral stimulus information. Research on this topic has not yet fully explored the mechanisms of interaction between traumatic and neutral content in the cognitive dynamics of PTSD.

ERP indices of working memory updating in AD/HD: differential aspects of development, subtype, and medication

This study investigated whether children and adolescents diagnosed with the predominantly inattentive and combined subtypes of attention deficit/hyperactivity disorder (AD/HD-in and AD/HD-com, respectively) differed on psychophysiological indices of working memory updating off- and on-stimulant medication, as compared with control subjects and each other. ERPs were recorded in AD/HD and control participants during a one-back working memory task. The N100 (discrimination), P150 (selection), N300 (memory retrieval), and P450wm (updating) components after nontarget stimuli, which served to update working memory with target identity, were assessed. Premedication abnormalities were obtained for the N300 component, delayed in the child AD/HD-com group, and attenuated in the adolescent AD/HD-in group and P450wm component for all AD/HD groups, expressed as either delayed latency and/or attenuated amplitude. ERP abnormalities were predominantly ameliorated after stimulant medication. There were no psychophysiological differences between the subtypes. A general feature of the disorder relates to a deficit in the conscious updating of working memory systems with newly relevant information (P450wm), which varies with age and subtype. Children with AD/HD-com and adolescents with AD/HD-in also exhibit abnormalities in the retrieval of relevant prior memories (N300). This study indicates that AD/HD is related to abnormalities in the capacity to modulate the content of working memory stores.

A randomized, two-year study of the efficacy of cognitive intervention on elderly people: the Donostia Longitudinal Study

BACKGROUND

Research on non-pharmacological therapies (cognitive rehabilitation) in old age has been very limited, and most has not considered the effect of interventions of this type over extended periods of time.

OBJECTIVE

To investigate a new cognitive therapy in a randomized study with elderly people who did not suffer cognitive impairment.

METHODS

The efficacy of this therapy was evaluated by means of post-hoc analysis of 238 people using biomedical, cognitive, behavioural, quality of life (QoL), subjective memory, and affective assessments.

RESULTS

Scores for learning potential and different types of memory (working memory, immediate memory, logic memory) for the treatment group improved significantly relative to the untreated controls.

CONCLUSIONS

The most significant finding in this study was that learning potential continued at enhanced levels in trained subjects over an intervention period lasting two years, thereby increasing rehabilitation potential and contributing to successful ageing.

Neuropsychology and clinical neuroscience of persistent post-concussive syndrome

On the mild end of the acquired brain injury spectrum, the terms concussion and mild traumatic brain injury (mTBI) have been used interchangeably, where persistent post-concussive syndrome (PPCS) has been a label given when symptoms persist for more than three months post-concussion. Whereas a brief history of concussion research is overviewed, the focus of this review is on the current status of PPCS as a clinical entity from the perspective of recent advances in the biomechanical modeling of concussion in human and animal studies, particularly directed at a better understanding of the neuropathology associated with concussion. These studies implicate common regions of injury, including the upper brainstem, base of the frontal lobe, hypothalamic-pituitary axis, medial temporal lobe, fornix, and corpus callosum. Limitations of current neuropsychological techniques for the clinical assessment of memory and executive function are explored and recommendations for improved research designs offered, that may enhance the study of long-term neuropsychological sequelae of concussion.

Enhanced effects of cortisol administration on episodic and working memory in aging veterans with PTSD

Though both glucocorticoid alterations and memory impairments have been noted in posttraumatic stress disorder (PTSD), it is not clear if these phenomena are causally linked. As there is emerging evidence that these domains become further altered in PTSD with increasing age, it is of interest to examine these relationships in an older cohort. Aging (mean age, 62.7+/-8.9; range, 52-81) combat veterans with (n=13) and without (n=17) PTSD received an intravenous bolus of 17.5 mg hydrocortisone (cortisol), a naturally occurring glucocorticoid, or placebo in a randomized, double-blind manner, on two mornings approximately 1-2 weeks apart. Neuropsychological testing to evaluate episodic and working memory performance was performed 75 min later. Cortisol enhanced episodic memory performance in both groups of subjects, but enhanced elements of working memory performance only in the PTSD+ group. The preferential effect of cortisol administration on working memory in PTSD may be related to the superimposition of PTSD and age, as cortisol had impairing effects on this task in a previously studied, younger cohort. The findings suggest that there may be opportunities for developing therapeutic strategies using glucocorticoids in the treatment of aging combat veterans.

Integrating genomics and neuromarkers for the era of brain-related personalized medicine

The harsh reality is that many medical treatments do not work as expected in a significant percentage of patients, and occasionally there are serious side effects. A new paradigm of personalized medicine is emerging, which proactively tailors treatment to each individual’s biological and psychological profile. The first proof-of-concept phase of personalized medicine has now been achieved. However, it has thus far focused on the use of genomic markers and on disorders of the body. The complexity of the brain is likely to require a shift from a single genetic marker focus to a more integrated approach in which additional brain-related information (neuromarkers) is taken into account. Codevelopment of genomic neuromarkers with new compounds in a personalized medicine approach will lead to increased drug R&D and treatment benefits. The emerging genomic neuromarker potential has begun to be incorporated into the template for the next version of the Diagnostic and Statistical Manual (DSM-V). The statistical power of large subject numbers in databases in general (and standardized databases in particular) provides an ideal source for elucidating the best genomic–neuromarker profiles (explaining most of the main-effects variance), which will empower a brain-related personalized medicine into mainstream clinical practice.

INTEGRATING OBJECTIVE GENE-BRAIN-BEHAVIOR MARKERS OF PSYCHIATRIC DISORDERS

There is little consensus about which objective markers should be used to assess major psychiatric disorders, and predict/evaluate treatment response for these disorders. Clinical practice relies instead on subjective signs and symptoms, such that there is a "translational gap" between research findings and clinical practice. This gap arises from: a) a lack of integrative theoretical models which provide a basis for understanding links between gene-brain-behavior mechanisms and clinical entities; b) the reliance on studying one measure at a time so that linkages between markers are their specificity are not established; and c) the lack of a definitive understanding of what constitutes normative function. Here, we draw on a standardized methodology for acquiring multiple sources of genomic, brain and behavioral data in the same subjects, to propose candidate markers of selected psychiatric disorders: depression, post-traumatic stress disorder, schizophrenia, attention-deficit/hyperactivity disorder and dementia disorders. This methodology has been used to establish a standardized international database which provides a comprehensive framework and the basis for testing hypotheses derived from an integrative theoretical model of the brain. Using this normative base, we present preliminary findings for a number of disorders in relation to the proposed markers. Establishing these objective markers will be the first step towards determining their sensitivity, specificity and treatment prediction in individual patients.

Effects of high-dose and conventional-dose adjuvant chemotherapy on long-term cognitive sequelae in patients with breast cancer: an electrophysiologic study

BACKGROUND

The mechanisms underlying cognitive deficits found in a number of patients with breast cancer treated with adjuvant chemotherapy are still unclear. In the current study, we used a combination of measures of brain electric activity and cognitive performance during information processing to elucidate the origin of these cognitive deficits.

PATIENTS AND METHODS

Twenty-nine patients at high risk with breast cancer treated with adjuvant conventional-dose cyclophosphamide/epirubicin/5-fluorouracil or adjuvant high-dose cyclophosphamide/thiotepa/carboplatin were compared with 23 patients with stage I breast cancer not treated with chemotherapy approximately 4 years after completion of treatment. We studied reaction times and the amplitudes and latencies of the P3, an electrophysiologic index of information processing, in a task with different conditions related to input, central, and output processing of information.

RESULTS

The amplitude of the P3 component was significantly reduced in patients with breast cancer treated with high-dose cyclophosphamide/thiotepa/carboplatin compared with patients with breast cancer not treated with chemotherapy. We observed no significant differences in reaction times and P3 latency between the treatment groups.

CONCLUSION

Our data show electrophysiologic alterations in patients with breast cancer treated with high-dose chemotherapy 4 years after completion of treatment. The observed P3 reduction might be a result of suboptimal phasic cortical arousal and problems with the allocation of processing resources in these patients.

INTEGRATIVE ASSESSMENT OF BRAIN FUNCTION IN PTSD: BRAIN STABILITY AND WORKING MEMORY

Posttraumatic Stress Disorder (PTSD) is characterized by symptoms of hyperarousal, avoidance and intrusive trauma-related memories and deficits in everyday memory and attention. Separate studies in PTSD have found abnormalities in electroencephalogram EEG, in event-related potential (ERP) and behavioral measures of working memory and attention. The present study seeks to determine whether these abnormalities are related and the extent to which they share this relationship with clinical symptoms. EEG data were collected during an eyes-open paradigm and a one-back working memory task. Behavioral and clinical data (CAPS) were also collected. The PTSD group showed signs of altered cortical arousal as indexed by reduced alpha power and an increased theta/alpha ratio, and clinical and physiological measures of arousal were found to be related. The normal relationship between theta power and ERP indices of working memory was not affected in PTSD, with both sets of measures reduced in the disordered group. Medication appeared to underpin a number of abnormal parameters, including P3 amplitude to targets and the accuracy, though not speed, of target detection. The present study helps to overcome a limitation of earlier studies that assess such parameters independently in different groups of patients that vary in factors such as comorbidity, medication status, gender and symptom profile. The present study begins to shed light on the relationship between these measures and suggests that abnormalities in brain working memory may be linked to underlying abnormalities in brain stability.