Attention, learning, and memory performances and intellectual resources in Vietnam veterans: PTSD and no disorder comparisons

Pattern of cognitive impairment in older veterans with posttraumatic stress disorder evaluated at a memory disorders clinic

BACKGROUND

We determined the pattern of clinically significant cognitive impairment (CI) among older veterans with posttraumatic stress disorder (PTSD) evaluated in a memory disorders clinic.

METHODS

Data were collected from 19 ethnically diverse veterans. Cognitive functioning in six domains (verbal learning, memory, attention, language, executive functioning, and information processing speed) was assessed.

RESULTS

The majority of veterans (57%) demonstrated CI on a measure of single trial list learning, 44% exhibited CI on short delay memory for lists, and 31% exhibited CI in long delay memory for lists. CI on measures of memory for stories (14%) and executive functioning (6%) were less common, and none of the participants demonstrated CI on measures of attention, language, or information processing speed.

CONCLUSIONS

CI on measures of single trial list learning and memory for lists are common in older patients with PTSD evaluated in a memory disorders clinic and are likely to contribute to functional deficits.

Predicting post-trauma stress symptoms from pre-trauma psychophysiologic reactivity, personality traits and measures of psychopathology

Background

Most individuals exposed to a traumatic event do not develop post-traumatic stress disorder (PTSD), although many individuals may experience sub-clinical levels of post-traumatic stress symptoms (PTSS). There are notable individual differences in the presence and severity of PTSS among individuals who report seemingly comparable traumatic events. Individual differences in PTSS following exposure to traumatic events could be influenced by pre-trauma vulnerabilities for developing PTSS/PTSD.

Methods

Pre-trauma psychological, psychophysiological and personality variables were prospectively assessed for their predictive relationships with post-traumatic stress symptoms (PTSS). Police and firefighter trainees were tested at the start of their professional training (i.e., pre-trauma; n = 211) and again several months after exposure to a potentially traumatic event (i.e., post-trauma, n = 99). Pre-trauma assessments included diagnostic interviews, psychological and personality measures and two psychophysiological assessment procedures. The psychophysiological assessments measured psychophysiologic reactivity to loud tones and the acquisition and extinction of a conditioned fear response. Post-trauma assessment included a measure of psychophysiologic reactivity during recollection of the traumatic event using a script-driven imagery task.

Results

Logistic stepwise regression identified the combination of lower IQ, higher depression score and poorer extinction of forehead (corrugator) electromyogram responses as pre-trauma predictors of higher PTSS. The combination of lower IQ and increased skin conductance (SC) reactivity to loud tones were identified as pre-trauma predictors of higher post-trauma psychophysiologic reactivity during recollection of the traumatic event. A univariate relationship was also observed between pre-trauma heart rate (HR) reactivity to fear cues during conditioning and post-trauma psychophysiologic reactivity.

Conclusion

The current study contributes to a very limited literature reporting results from truly prospective examinations of pre-trauma physiologic, psychologic, and demographic predictors of PTSS. Findings that combinations of lower estimated IQ, greater depression symptoms, a larger differential corrugator EMG response during extinction and larger SC responses to loud tones significantly predicted higher PTSS suggests that the process(es) underlying these traits contribute to the pathogenesis of subjective and physiological PTSS. Due to the low levels of PTSS severity and relatively restricted ranges of outcome scores due to the healthy nature of the participants, results may underestimate actual predictive relationships.

The contributions of self-reported injury characteristics and psychiatric symptoms to cognitive functioning in OEF/OIF veterans with mild traumatic brain injury

Mild traumatic brain injury (mTBI) affects a significant number of combat veterans returning from Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF). Although resolution of mTBI symptoms is expected over time, some individuals continue to report lingering cognitive difficulties. This study examined the contributions of self-reported mTBI injury characteristics (e.g., loss of consciousness, post-traumatic amnesia) and psychiatric symptoms to both subjective and objective cognitive functioning in a sample of 167 OEF/OIF veterans seen in a TBI clinic. Injury characteristics were not associated with performance on neuropsychological tests but were variably related to subjective ratings of cognitive functioning. Psychiatric symptoms were highly prevalent and fully mediated most of the relationships between injury characteristics and cognitive ratings. This indicates that mTBI characteristics such as longer time since injury and loss of consciousness or post-traumatic amnesia can lead to increased perceived cognitive deficits despite having no objective effects on cognitive performance. Psychiatric symptoms were associated with both cognitive ratings and neuropsychological performance, illustrating the important role that psychiatric treatment can potentially play in optimizing functioning. Finally, subjective cognitive ratings were not predictive of neuropsychological performance once psychiatric functioning was statistically controlled, suggesting that neuropsychological assessment provides valuable information that cannot be gleaned from self-report alone.

The effects of child abuse and neglect on cognitive functioning in adulthood

AIMS

Recent research has revealed that early life trauma (ELS), including abuse (sexual and/or physical) and neglect, produce lasting changes in the CNS. We posited that cognitive deficits, often observed in psychiatric patients, result, in part, due to the neurobiological consequences of ELS. Additionally, we hypothesized that the nature and magnitude of cognitive deficits would differ according to the subtype of ELS experienced.

METHOD

The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to assess neurocognitive functioning in 93 subjects (60 with ELS and 33 without). In the patients with a history of ELS, 35% and 16.7%, respectively, met criteria for current major depression and PTSD.

RESULTS

Significant associations between ELS status and CANTAB measures of memory and executive and emotional functioning were found.

CONCLUSIONS

These data suggest that exposure to ELS results in a cascade of neurobiological changes associated with cognitive deficits in adulthood that vary according to the type of trauma experienced.

Neurocognitive performance in drug-dependent males and females with posttraumatic stress disorder symptoms

Sex differences in neurobiological mechanisms of substance dependence are well documented but studies of sex differences in associated neurocognitive deficits have produced inconsistent results. Posttraumatic stress disorder (PTSD) is comorbid with substance dependence and frequently affects neurocognition. Thus, we investigated the effects of sex and PTSD symptoms on sustained attention and inhibition abilities among 126 female and 297 male substance-dependent individuals (SDIs) using the Immediate Memory Test (IMT). Females with significant PTSD (PTSD+) symptoms demonstrated significantly impaired IMT performance relative to other participants. These results represent progress in efforts to delineate sex-specific risk factors for neurocognitive deficits among SDIs.

Neuropsychological sequelae of PTSD and TBI following war deployment among OEF/OIF veterans

Posttraumatic stress disorder (PTSD) and mild traumatic brain injury (mTBI) are highly prevalent among Veterans of the conflicts in Iraq and Afghanistan. These conditions are associated with common and unique neuropsychological and neuroanatomical changes. This review synthesizes neuropsychological and neuroimaging studies for both of these disorders and studies examining their co-occurrence. Recommendations for future research, including use of combined neuropsychological and advanced neuroimaging techniques to study these disorders alone and in concert, are presented. It is clear from the dearth of literature that addiitonal studies are required to examine and understand the impact of specific factors on neurocognitive outcome. Of particular relevance are temporal relationships between PTSD and mTBI, risk and resilience factors associated with both disorders and their co-occurrence, and mTBI-specific factors such as time since injury and severity of injury, utilizing comprehensive, yet targeted cognitive tasks.

Executive function and PTSD: disengaging from trauma

Neuropsychological approaches represent an important avenue for identifying susceptibility and resiliency factors relating to the development and maintenance of posttraumatic stress disorder (PTSD) symptoms post-trauma. This review will summarize results from prospective longitudinal and retrospective cross-sectional studies investigating executive function associated with PTSD. This research points specifically towards subtle impairments in response inhibition and attention regulation that may predate trauma exposure, serve as risk factors for the development of PTSD, and relate to the severity of symptoms. These impairments may be exacerbated within emotional or trauma-related contexts, and may relate to dysfunction within dorsal prefrontal networks. A model is presented concerning how such impairments may contribute to the clinical profile of PTSD and lead to the use of alternative coping styles such as avoidance. Further neuropsychological research is needed to identify the effects of treatment on cognitive function and to potentially characterize mechanisms of current PTSD treatments. Knowledge gained from cognitive and neuroscientific research may prove valuable for informing the future development of novel, more effective, treatments for PTSD. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Source imaging of P300 auditory evoked potentials and clinical correlations in patients with posttraumatic stress disorder

OBJECTIVE

Posttraumatic stress disorder (PTSD) is associated with abnormal information processing. The P300 component of event-related potentials (ERPs) is known to be a useful marker of information processing. The purposes of this study were to determine the P300 current source density in PTSD patients, and its relationship with symptom severity.

METHODS

ERPs were recorded in 30 PTSD patients and 33 healthy controls while participants were performing the auditory oddball task. We compared P300 current source density data--obtained by standardized low-resolution brain electromagnetic tomography (sLORETA)--between the two groups. The correlation between P300 current source density and clinical symptoms (as evaluated using the Korean version of the Structured Interview for PTSD--K-SIPS and Davidson Trauma Scale--K-DTS) was conducted.

RESULTS

In PTSD patients, the current source density of P300 is significantly reduced in the inferior frontal gyrus, precentral gyrus, insula, and anterior cingulate compared to healthy controls. Total K-DTS scores were correlated with the P300 current source density in the posterior cingulate gyrus. The K-SIP B items (re-experiencing) and K-SIB D items (increased arousal) were positively correlated with P300 current source densities in several brain regions located in the frontal, parietal, and temporal lobe (p<0.05). Conversely, the K-SIP C items (avoidance and numbing) were negatively correlated with P300 current source densities in the superior and middle frontal gyri in the frontal lobes (p<0.05).

CONCLUSION

The P300 current source densities reflected the pathophysiology of PTSD patients. PTSD symptoms were related to different neural activities, depending on their symptom characteristics.

Neuropsychological and neuroimaging findings in traumatic brain injury and post-traumatic stress disorder

Advances in imaging technology, coupled with military personnel returning home from Iraq and Afghanistan with traumatic brain injury (TBI) and/or post-traumatic stress disorder (PTSD), have increased interest in the neuropsychology and neurobiology of these two conditions. There has been a particular focus on differential diagnosis. This paper provides an overview of findings regarding the neuropsychological and neurobiological underpinnings of TBI and for PTSD. A specific focus is on assessment using neuropsychological measures and imaging techniques. Challenges associated with the assessment of individuals with one or both conditions are also discussed. Although use of neuropsychological and neuroimaging test results may assist with diagnosis and treatment planning, further work is needed to identify objective biomarkers for each condition. Such advances would be expected to facilitate differential diagnosis and implementation of best treatment practices.

Post-traumatic stress disorder and declarative memory functioning: a review

Declarative memory dysfunction is associated with post-traumatic stress disorder (PTSD). This paper reviews this literature and presents two frameworks to explain the nature of this dysfunction: that memory deficits are a product of neurobiological abnormalities caused by PTSD andlor that pre-existing memory deficits serve as a risk factor for the development of PTSD following trauma exposure. Brain regions implicated in declarative memory deficits include the hippocampus and prefrontal cortex, and imaging and biochemistry studies as they relate to memory dysfunction are described. Prospective and twin studies provide support for a risk factor model.

How understanding the neurobiology of complex post-traumatic stress disorder can inform clinical practice: a social cognitive and affective neuroscience approach

OBJECTIVE

In this review, we examine the relevance of the social cognitive and affective neuroscience (SCAN) paradigm for an understanding of the psychology and neurobiology of complex post-traumatic stress disorder (PTSD) and its effective treatment.

METHOD

The relevant literature pertaining to SCAN and PTSD was reviewed.

RESULTS

We suggest that SCAN offers a novel theoretical paradigm for understanding psychological trauma and its numerous clinical outcomes, most notably problems in emotional/self-awareness, emotion regulation, social emotional processing and self-referential processing. A core set of brain regions appear to mediate these collective psychological functions, most notably the cortical midline structures, the amygdala, the insula, posterior parietal cortex and temporal poles, suggesting that problems in one area (e.g. emotional awareness) may relate to difficulties in another (e.g. self-referential processing). We further propose, drawing on clinical research, that the experiences of individuals with PTSD related to chronic trauma often reflect impairments in multiple social cognitive and affective functions.

CONCLUSION

It is important that the assessment and treatment of individuals with complex PTSD not only addresses traumatic memories but also takes a SCAN-informed approach that focuses on the underlying deficits in emotional/self-awareness, emotion regulation, social emotional processing and self-referential processing.

A prospective examination of the relationships between PTSD, exposure to assaultive violence, and cigarette smoking among a national sample of adolescents

Research demonstrates robust associations among posttraumatic stress disorder (PTSD), exposure to assaultive violence (i.e., sexual assault, physical assault, and witnessed violence), and cigarette smoking among adults and adolescents. Whether exposure to assaultive violence confers risk for cigarette smoking over and above the effects of PTSD and non-assaultive traumatic events (e.g., motor vehicle accidents) is unclear. The current study prospectively measured PTSD, assaultive violence exposure, non-assaultive traumatic event exposure, and cigarette smoking three times over approximately three years among a nationally representative sample of adolescents (N=3614, age range 12-17 at Wave 1). Results revealed that multiple exposure to assaultive violence at Wave 1 was a consistent and robust prospective predictor of cigarette smoking at Waves 2 and 3. By contrast, PTSD diagnoses and non-assaultive traumatic event exposures at Wave 1 only predicted cigarette smoking at Wave 2, but not at Wave 3. Theoretical and clinical implications are discussed.

Media use by children and adolescents from New York City 6 months after the WTC attack

Six months after the World Trade Center (WTC) attacks of September 11, 2001 (9/11), a representative sample of New York City students (N = 8,236) in Grades 4 through 12 reported their use of TV, Web, and combined radio and print media regarding the WTC attack. Demographic factors, WTC exposure, other exposure to trauma, and probable posttraumatic stress disorder (PTSD) were used to predict intensive use of the 3 types of media. Intensive use was associated with direct exposure to the WTC attack (with the exception of Web use) and to having reported symptoms of PTSD. Stratified analyses indicated that the association between probable PTSD and intensive media use was more consistently present among those who had no direct or familial exposure to the WTC attack. As well, media, particularly TV, was intensively used by children after the WTC attack. Variations existed in the factors associated with intensive media use, which should be considered when planning postdisaster media coverage and advising families.

Exaggerated activation of dorsal anterior cingulate cortex during cognitive interference: a monozygotic twin study of posttraumatic stress disorder

OBJECTIVE

Neuroimaging studies have revealed functional abnormalities in the anterior cingulate cortex in posttraumatic stress disorder (PTSD). The goal of this study was to determine whether hyperresponsivity of the dorsal anterior cingulate in PTSD is an acquired characteristic or a familial risk factor.

METHOD

Using a case-control twin design, the authors studied combat-exposed veterans with PTSD (N=12) and their identical combat-unexposed co-twins (N=12), as well as combat-exposed veterans without PTSD (N=14) and their identical combat-unexposed co-twins (N=14). Participants underwent functional MRI during completion of the Multi-Source Interference Task, which reliably activates the dorsal anterior cingulate.

RESULTS

Combat-exposed veterans with PTSD and their unexposed co-twins had significantly greater activation in the dorsal anterior cingulate and tended to have larger response time difference scores, as compared to combat-exposed veterans without PTSD and their co-twins. Dorsal anterior cingulate activation in the exposed twins was positively correlated with their PTSD symptom severity. Dorsal anterior cingulate activation in the unexposed twins was positively correlated with their combat-exposed co-twins' PTSD symptom severity, but not with depression or alcohol use severity in the combat-exposed co-twins.

CONCLUSIONS

Hyperresponsivity in the dorsal anterior cingulate appears to be a familial risk factor for the development of PTSD following psychological trauma.

A specific deficit in spatial memory acquisition in post-traumatic stress disorder and the role of sleep in its consolidation

Posttraumatic stress disorder (PTSD) is characterized by the presence of anatomo-functional hippocampal alterations. To date, the ability to orient within the environment, which relies on hippocampal integrity, has never been investigated in PTSD. We hypothesized that the ability to form a cognitive map of the environment would be impaired in PTSD. Moreover, spatial memory consolidation benefits from postlearning sleep. Because PTSD individuals often complain about sleep disturbances, we hypothesized that any sleep effect on memory performance would be hampered in these subjects. Twenty-two subjects, all survivors of the L'Aquila 2009 earthquake, were divided into a PTSD and a control group, based on clinical evaluation. After an acquisition phase, they were tested twice ("test" and "retest") on a virtual navigation task. In addition, participants were administered the Digit Span and Task Switching. Subjective sleep quality and sleep disturbances were also assessed. The two testing sessions were on consecutive mornings, interspersed with a night of sleep. During the acquisition phase, the PTSD group took more than twice as long to form a cognitive map of the environment compared to the control group. However, once this phase was successfully completed, the two groups did not differ at test, but they tendentially differed at postsleep retest. Additional analyses comparing performances between groups on test-retest difference scores confirm that sleep-dependent consolidation may be differentially affected in the two groups. Our findings are strictly confined to the navigation performance, excluding a generalized cognitive deficit. PTSD also reported more subjective sleep disturbances and shorter sleep time than controls, which were correlated to worse performance at retest. The specific deficit in the formation of a cognitive map reported in PTSD may be related to hippocampal dysfunctions as well as to the sleep disturbances experienced by these patients. The possible deficiency of sleep-dependent spatial performance improvement should however be confirmed by further studies comprising a wake control group.

The relationship between posttraumatic stress disorder and smoking outcome expectancies among U.S. military veterans who served since September 11, 2001

Posttraumatic stress disorder (PTSD) is associated with increased rates of smoking although little is known regarding the mechanisms underlying this relationship. The current study examined expectations about smoking outcomes among smokers with and without PTSD. The sample included 96 veterans (mean age of 34 years) and included 17% women and 50% racial minorities. Smoking expectancies were measured with the Smoking Consequences Questionnaire-Adult (Copeland, Brandon, & Quinn, 1995). Consistent with previous work suggesting that smokers with PTSD smoke in an effort to reduce negative affect, unadjusted analyses indicated that smokers with PTSD (n = 38) had higher expectations that smoking reduces negative affect than smokers without PTSD (d = 0.61). Smokers with PTSD also had increased expectancies associated with boredom reduction (d = 0.48), stimulation (d = 0.61), taste/sensorimotor manipulation aspects of smoking (d = 0.73), and social facilitation (d = 0.61). Results of hierarchical linear regression analyses indicated that PTSD symptom severity was uniquely associated with these expectancies beyond the effects of gender and nicotine dependence. More positive beliefs about the consequences of smoking may increase risk of continued smoking among those with PTSD who smoke. Further understanding of smoking expectancies in this group may help in developing interventions tailored for this vulnerable population.

Hippocampal dysfunction effects on context memory: possible etiology for posttraumatic stress disorder

Hippocampal volume reductions and functional impairments are reliable findings in posttraumatic stress disorder (PTSD) imaging studies. However, it is not clear if and how hippocampal dysfunction contributes to the etiology and maintenance of PTSD. Individuals with PTSD are often described as showing fear responses to trauma reminders outside of contexts in which these cues would reasonably predict danger. Animal studies suggest that the hippocampus is required to form and recall associations between contextual stimuli and aversive events. For example, the hippocampus is critical for encoding memories in which a complex configuration of multiple cues is associated with the aversive event. Conversely, the hippocampus is not required for associations with discrete cues. In animal studies, if configural memory is disrupted, learning strategies using discrete cue associations predominate. These data suggest poor hippocampal function could bias the organism toward forming multiple simple cue associations during trauma, thus increasing the chances of fear responses in multiple environments (or contexts) in which these cues may be present. Here we will examine clinical and preclinical literature to support a theory of hippocampal dysfunction as a primary contributory factor to the etiology of PTSD, and discuss future research required to test these hypotheses. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Adolescent posttraumatic stress disorder: an examination of factor structure reliability in two national samples

A four-factor structure of posttraumatic stress disorder (PTSD) has been proposed for DSM-V based on empirical evidence that it is superior to the three-factor DSM-IV structure. However, most studies reveal multiple structures fit the data well in adolescent samples, and high factor correlations have been reported. Within two national samples of adolescents, we tested eight PTSD factor structures, which have never been compared in a single study. Confirmatory factor analyses (CFA) of PTSD symptoms were conducted in two national samples of adolescents: the National Survey of Adolescents (NSA; N = 4023) and the NSA-Replication (NSA-R; N = 3614). CFA revealed that all models provided very good fit to both samples (RMSEAs = .021-.039), though the one-factor model can be rejected, and correlations between factors were high (rs = .80-1.0). Potential interpretations of these findings include: (1) the indicators (i.e., symptoms) need refinement; or (2) relevant symptoms have yet to be identified.

No effect of PTSD and other psychiatric disorders on cognitive functioning in veterans with mild TBI

There has been speculation that post-traumatic stress disorder (PTSD) superimposed on mild traumatic brain injury (mTBI) may have synergistic, negative effects on cognitive functioning. The purpose of this study was to investigate differences in processing speed, executive functioning, and memory of 82 veterans with mTBI and PTSD, mTBI, and another psychiatric condition, or mTBI alone. It was hypothesized that there would be no group differences in cognitive performances. Participants completed the Trail Making Test, Stroop, Rey Complex Figure, and California Verbal Learning Test-2. There were no significant group differences on any cognitive measure. Findings suggest that PTSD and other psychiatric disorders do not necessarily have a negative exacerbating effect on processing speed, executive functioning, or memory in veterans with mTBI.

Assessment of cognitive functions in individuals with post-traumatic symptoms after work-related accidents

The investigation of cognitive functions in individuals who developed post-traumatic symptoms after occupational accidents has been overlooked in the relevant literature. The present study was aimed at assessing attention, memory and executive functions in individuals with post-traumatic symptoms after a workplace accident. Moreover, possible presence of emotional interference from trauma-related cues on attentional performance was evaluated. Results showed that injured workers exhibited deficits in perceptual-psychomotor skills, executive functions, attention and concentration abilities, and memory as compared with healthy controls. With regards to emotional interference on attention, injured workers were found to perform significantly worse than controls specifically when exposed to trauma-related pictures. Overall, these findings suggest that post-traumatic symptoms following a workplace accident are associated with several cognitive and emotional dysfunctions, that should be carefully evaluated to help reduce the frequency and the adverse consequences of occupational accidents.

Glucocorticoid augmentation of prolonged exposure therapy: rationale and case report

RATIONALE

Prolonged exposure (PE) therapy has been found to reduce symptoms of posttraumatic stress disorder (PTSD); however, it is difficult for many patients to engage fully in the obligatory retelling of their traumatic experiences. This problem is compounded by the fact that habituation and cognitive restructuring - the main mechanisms through which PE is hypothesized to work - are not instantaneous processes, and often require several weeks before the distress associated with imaginal exposure abates.

CASE REPORTS

Two cases are described that respectively illustrate the use of hydrocortisone and placebo, in combination with PE, for the treatment of combat-related PTSD. Based on known effects of glucocorticoids on learning and memory performance, we hypothesized that augmentation with hydrocortisone would improve the therapeutic effects of PE by hastening "new" learning and facilitating decreases in the emotional impact of fear memories during the course of treatment. The veteran receiving hydrocortisone augmentation of PE displayed an accelerated and ultimately greater decline in PTSD symptoms than the veteran receiving placebo.

CONCLUSIONS

While no general conclusion can be derived from comparison of two patients, the findings are consistent with the rationale for augmentation. These case reports support the potential for an appropriately designed and powered clinical trial to examine the efficacy of glucocorticoids in augmenting the effects of psychotherapy for PTSD.

Dichotic listening performance suggests right hemisphere involvement in PTSD

The present study focuses on language laterality as measured with dichotic listening (DL) to consonant-vowel syllables (CV syllables) in refugees with post-traumatic stress disorder (PTSD). PTSD is associated with impaired callosal transfer and with increased right hemisphere activation and impaired executive skills that could influence the processing of dichotic stimuli. A total of 22 participants with PTSD were compared to 23 participants without a diagnosis of PTSD. All participants had similar experiences of acts of war and political violence. They were tested with dichotic listening to CV syllables with free recall and directed attention following the forced attention paradigm. The PTSD group showed increased right ear advantage due to impaired left ear reporting and also smaller attention modulation compared to the control group, and the performance shared variance with self-report measures of arousal and intrusive memories. The results are discussed towards a model of impaired functionality of the frontal lobe and right hemisphere versus impaired callosal transfer, both yielding predictions for the processing of the left ear input and the ability to attention modulation of the performance.

Effects of psychological and biomechanical trauma on brain and behavior

The current conflicts in Iraq and Afghanistan have resulted in a large cohort of military personnel exposed to combat-related psychological trauma as well as biomechanical trauma, including proximity to blast events. Historically, the long-term effects of both types of trauma have been viewed as having different neural substrates, with some controversy over the proper attribution of such symptoms evident after each of the major conflicts of the last century. Recently, great effort has been directed toward distinguishing which neuropsychiatric sequelae are due to which type of trauma. Of interest, however, is that the chronic effects of exposure to either process are associated with a significant overlap in clinical symptoms. Furthermore, similar brain regions are vulnerable to the effects of either psychological or biomechanical trauma, raising the possibility that shared mechanisms may underlie the clinically observed overlap in symptom profile. This paper reviews the literature on the neural substrate of biomechanical and psychological injury and discusses the implications for evaluation and treatment of the neuropsychiatric sequelae of these processes.

Effects of chronic and acute stress on rat behaviour in the forced-swim test

Stress and depression may share common neural plasticity mechanisms. Importantly, the development and reversal of stress-induced plasticity requires time. These temporal aspects, however, are not captured fully in the forced-swim test (FST), a behavioural model for testing antidepressant efficacy, used originally in naïve animals. The present study probed whether and how a rodent model of stress affects behaviour in the FST over time. We found that the intensity and duration of stress are critical in the development of depressive symptoms in male Wistar rats (n = 37) as tested in the FST. Chronic immobilization stress (2 h/day for 10 days) elicited a range of responses, from low to high values of immobility in the FST on day 1, and subsequent immobility on day 2 was inversely related to individual day 1 values. As a whole, chronically stressed rats did not exhibit any significant change in immobility either on day 1 or day 2 compared to control rats. However, climbing behaviour was reduced uniformly from day 1 to day 2, despite the differences in immobility. In contrast, a separate group of rats (n = 30) subjected to the same chronic stressor displayed a significant reduction in open-arm exploration in the elevated plus maze, indicative of a robust increase in anxiety-like behaviour. Furthermore, when the 10-day chronic stress paradigm was reduced to a single 2-h episode of immobilization stress, it triggered a uniform day 1 to day 2 increase in immobility, which was not persistent 10 days later. These results highlight a need for closer examination of the ways in which stress-induced modulation of behaviour in the FST may be used and interpreted in future studies aimed at exploring connections between stress and depression.

Pre-Stressor Interference Control and Intrusive Memories

Although intrusive imagery is a common response in the aftermath of a stressful or traumatic event, only a minority of trauma victims show persistent re-experiencing and related psychopathology. Individual differences in pre-trauma executive control possibly play a critical role. Therefore, this study investigated whether a relatively poor pre-stressor ability to resist proactive interference in working memory might increase risk for experiencing undesirable intrusive memories after being exposed to a stressful event. Non-clinical participants (N = 85) completed a modified version of a widely used test of interference control in working memory (CVLT; Kramer and Delis 1991) and subsequently watched an emotional film fragment. Following presentation of the fragment, intrusive memories were recorded in a 1-week diary and at a follow up session 7 days later. A relatively poor ability to resist proactive interference was related to a relatively high frequency of film-related intrusive memories. This relationship was independent of neuroticism and gender. These findings are consistent with the idea that a pre-morbid deficit in the ability to resist proactive interference reflects a vulnerability factor for experiencing intrusive memories after trauma exposure.

From hysteria and shell shock to posttraumatic stress disorder: comments on psychoanalytic and neuropsychological approaches

In this paper, we look back at some of the earliest psychoanalytic approaches to trauma. The theoretical feasibility of reconciling psychoanalytic and neurobiological accounts of the effects of severe stress is examined. First, several epistemic considerations about the concepts of falsifiability and complexity in science are discussed with regard to neuroscience and psychoanalysis. We report the decisive discussions and descriptions of shell shock and hysteria that laid the foundation for the modern notions of dissociation and posttraumatic stress disorder (PTSD). We particularly underline the differences between "traumatic memory", which merely and unconsciously repeats the past, and "narrative memory", which narrates the past as past. Then, the construction of the modern concept of PTSD is described and the classification of conversion and dissociative disorders is questioned. In the next section, several recent neurobiological findings in patients with PTSD are reviewed. We place particular emphasis on cognitive impairment and cognitive bias relative to threatening stimuli, and on a general pattern of facilitated and heightened activation of the amygdala for threat-related stimuli, which are both recognized symptoms of PTSD. A possible meeting point between Cannon's and Freud's theoretical concepts is discussed in the frame of a deregulation of the stress system which helps not only to regulate homeostasis but also to adjust behaviour to external threats. We conclude that, although psychoanalysis and neuroscience may reciprocally complement and enlighten each other, their objects and methods, and thence their concepts, are fundamentally different.

Attention to novel and target stimuli in trauma survivors

Trauma and its consequences can have lasting biological and cognitive effects on those who experience them. This study investigated the extent to which trauma, posttraumatic stress disorder (PTSD), and dissociation influenced attention to basic auditory stimuli in a sample of military cadets. After filling out a series of psychometric questionnaires, 27 male military cadets varying in their trauma history participated in the "novelty" oddball task in which participants were asked to count high-pitched tones while ignoring other auditory stimuli. Electroencephalogram (EEG) was continually recorded in order to assess P300 responses, an event-related potential (ERP) associated with attention and memory processes. Trauma history only, and not dissociation or PTSD scores, predicted smaller P300 amplitudes to target tones. To distracting novel sounds, only trauma history and dissociation predicted unique variance in P300 amplitudes. The findings suggest that PTSD may not be central to the attentional disturbances found in traumatized samples, while trauma history and dissociation may play a more important role. Future studies investigating attentional processes post trauma should utilize dissociation scales and a non-trauma sample.

Switching between executive and default mode networks in posttraumatic stress disorder: alterations in functional connectivity

Working memory processing and resting-state connectivity in the default mode network are altered in patients with posttraumatic stress disorder (PTSD). Because the ability to effortlessly switch between concentration on a task and an idling state during rest is implicated in both these alterations, we undertook a functional magnetic resonance imaging study with a block design to analyze task-induced modulations in connectivity.

METHODS

We performed a working memory task and psychophysiologic interaction analyses with the posterior cingulate cortex and the medial prefrontal cortex as seed regions during fixation in 12 patients with severe, chronic PTSD and 12 healthy controls.

RESULTS

During the working memory task, the control group showed significantly stronger connectivity with areas implicated in the salience and executive networks, including the right inferior frontal gyrus and the right inferior parietal lobule. The PTSD group showed stronger connectivity with areas implicated in the default mode network, namely enhanced connectivity between the posterior cingulate cortex and the right superior frontal gyrus and between the medial prefrontal cortex and the left parahippocampal gyrus.

LIMITATIONS

Because we were studying alterations in patients with severe, chronic PTSD, we could not exclude patients taking medication. The small sample size may have limited the power of our analyses. To avoid multiple testing in a small sample, we only used 2 seed regions for our analyses.

CONCLUSION

The different patterns of connectivity imply significant group differences with task-induced switches (i.e., engaging and disengaging the default mode network and the central-executive network).

Memory and executive dysfunctions associated with acute posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) in its chronic form has been associated with a number of neurocognitive impairments involving emotionally neutral stimuli. It remains unknown whether such impairments also characterize acute PTSD. In the present investigation, neurocognitive functions were examined in trauma exposed individuals with (n=21) and without (n=16) acute PTSD, as well as in a group of individuals never exposed to trauma (n=17) using specific and standardized tasks such as the Rey Auditory Verbal Learning Test, the Aggie's Figure Learning Test, the Autobiographical Memory Interview, the D2 test, the Stroop task, the digit and visual span tasks of the Wechsler Memory Scale-III, the Trail Making Test, the Tower of London and the vocabulary subtest of the Wechsler Adult Intelligence Scale-III. A number of deficits in the cognitive domains of memory, high-level attentional resources, executive function and working memory were found in the group with a diagnosis of acute PTSD only and not among the other groups. The findings, which point to the possibility of disturbed fronto-temporal system function in trauma-exposed individuals with acute PTSD, are particularly relevant for the early clinical management of this disorder.

Does neuroimaging research examining the pathophysiology of posttraumatic stress disorder require medication-free patients?

BACKGROUND

In an attempt to avoid unknown influence, most neuroimaging studies examining the pathophysiology of posttraumatic stress disorder (PTSD) exclude patients taking medications. Here we review the empirical evidence for relevant medications having a confounding effect on task performance or cerebral blood flow (CBF) in this population. The evidence for potentially confounding effects of psychotherapy in PTSD are also discussed.

METHODS

The literature that we reviewed was obtained through a PubMed search from 1980 to 2009 using the search terms posttraumatic stress disorder, PTSD, psychotropic medications, neuroimaging, functional magnetic resonance imaging, positron emission tomography, cerebral blood flow, CBF, serotonin-specific reuptake blocker, benzodiazepine, ketamine, methamphetamine, lamotrigine and atypical antipsychotic agents.

RESULTS

The empirical evidence for relevant medications having a confounding effect on task performance or CBF in relevant areas remains sparse for most psychotropic medications among patients with PTSD. However, considerable evidence is accumulating for 2 of the most commonly prescribed medication classes (serotonin-specific reuptake inhibitors and benzodiazepines) in healthy controls. Compelling data for the potentially confounding effects on brain areas relevant to PTSD for psychotherapeutic interventions are also accumulating.

CONCLUSION

Neuroimaging studies examining the pathophysiology of PTSD should ideally recruit both medicated (assuming that the medication treatment has not resulted in the remission of symptoms) and unmedicated participants, to allow the findings to be generalized with greater confidence to the entire population of patients with PTSD. More research is needed into the independent effects of medications on task performance and CBF in regions of interest in PTSD. Neuroimaging studies should also take into account whether patients are currently engaged in psychotherapeutic treatment.

Biomarkers for the diagnosis, prognosis, and evaluation of treatment efficacy for traumatic brain injury

Traumatic brain injury (TBI) remains a serious health concern, and TBI is one of the leading causes of death and disability, especially among young adults. Although preventive education, increased usage of safety devices, and TBI management have dramatically increased the potential for surviving a brain injury, there is still a need to develop reliable methods to diagnose TBI, the secondary pathologies associated with TBI, and predicting the outcomes of TBI. Biomarkers (changes of amount or activity in a biomolecule that reflect injury or disease) have shown promise in the diagnosis of several conditions, including cancer, heart failure, infection, and genetic disorders. A variety of proteins, small molecules, and lipid products have been proposed as potential biomarkers of brain damage from TBI. Although some of these changes have been reported to correlate with mortality and outcome, further research is required to identify prognostic biomarkers. This need is punctuated in mild injuries that cannot be readily detected using current techniques, as well as in defining patient risk for developing TBI-associated secondary injuries.

The influence of pre-deployment neurocognitive functioning on post-deployment PTSD symptom outcomes among Iraq-deployed Army soldiers

This study evaluated associations between pre-deployment neurocognitive performance and post-deployment posttraumatic stress disorder (PTSD) symptoms in a sample of deployed active duty Army soldiers. As part of a larger longitudinal study, each participant completed baseline measures of memory, executive attention, and response inhibition, and baseline and post-deployment self-report measures of PTSD symptom severity. Data were subjected to multiple regression analyses that examined associations between baseline neurocognitive performances and longitudinal PTSD symptom outcome. Results revealed that pre-trauma immediate recall of visual information was associated with post-deployment PTSD symptom severity, even after controlling for pre-deployment PTSD symptom levels, combat intensity, age, gender, and test-retest interval. There was also an interaction between pre-deployment PTSD symptom severity and pre-deployment immediate visual recall and verbal learning, indicating that neurocognitive performances were more strongly (and negatively) associated with residualized post-deployment PTSD symptoms at higher levels of pre-deployment PTSD symptoms. These findings highlight the potential role of pre-trauma neurocognitive functioning in moderating the effects of trauma exposure on PTSD symptoms

Longitudinal effects of PTSD on memory functioning

Numerous studies have demonstrated explicit and working memory deficits related to posttraumatic stress disorder (PTSD), but few have addressed longitudinal changes in memory functioning. There is some evidence to suggest an interactive effect of PTSD and aging on verbal memory decline in Holocaust survivors (Yehuda et al., 2006). However, the longitudinal trajectory of neuropsychological functioning has not been investigated in Vietnam veterans, a younger but substantial population of aging trauma survivors. We administered tests of visual and verbal memory, and working memory to derive different dependent measures in veterans between the ages of 41 and 63, the majority of whom served in the Vietnam War. Twenty-five veterans with PTSD and 22 veterans without PTSD were assessed over two time points (mean age at follow-up = 54.0; mean inter-test interval = 34 months). The PTSD+ group, consisting of veterans with chronic, primarily combat-related PTSD, did not show a significant change in PTSD symptoms over time. Compared to veterans without PTSD, veterans with PTSD showed a greater decline in delayed facial recognition only, and this decline was extremely subtle.

Cognitive impairment and functioning in PTSD related to intimate partner violence

Posttraumatic stress disorder (PTSD) has been associated with neuropsychological impairments across multiple domains, but consensus regarding the cognitive profile of PTSD has not been reached. In this study of women with PTSD related to intimate partner violence (n = 55) and healthy, demographically similar comparison participants (NCs; n = 20), we attempted to control for many potential confounds in PTSD samples. All participants were assessed with a comprehensive neuropsychological battery emphasizing executive functioning, including inhibition, switching, and abstraction. NCs outperformed PTSD participants on most neuropsychological measures, but the differences were significant only on speeded tasks (with and without executive functioning components). The PTSD group's mean performance was within the average range on all neuropsychological tests. Within the PTSD group, more severe PTSD symptoms were associated with slower processing speed, and more severe dissociative symptoms were associated with poorer reasoning performance. These results suggest that women with PTSD related to intimate partner violence demonstrate slower than normal processing speed, which is associated with the severity of psychiatric symptoms. We speculate that the cognitive slowing seen in PTSD may be attributable to reduced attention due to a need to allocate resources to cope with psychological distress or unpleasant internal experiences.

Neuropsychological functioning in children with posttraumatic stress disorder

Posttraumatic stress disorder (PTSD) has been associated with deficits in the areas of verbal memory and learning, executive functioning, working memory, and attention in adults. Findings have been less consistent in the few studies examining neuropsychological functioning in childhood PTSD, which are often limited by comparing children with PTSD to children without trauma histories, making it unclear whether observed neuropsychological deficits are related to trauma exposure or to PTSD symptomatology. In an ethnically diverse sample of 62 children who witnessed intimate partner violence (n = 27 PTSD+ and 35 PTSD-), children with PTSD exhibited slower and less effective learning, heightened sensitivity to interference, and impaired effect of rehearsal on memory acquisition on the California Verbal Learning Test - Children's Version, a word list learning task. Both groups performed in the below average range on measures of executive functioning, attention, and intellectual ability.

Maternal inexperience as a risk factor of innate fear and PTSD-like symptoms in mice

In laboratory rats and mice, differences in maternal care during the first week of life have been shown to exert long-lasting consequences on cognitive functioning and stress processing of the offspring. Such epigenetic programming is also assumed to play an important role in the transgenerational transmission of PTSD in humans. Here we studied whether even subtle within-subject differences in maternal care - caused by increasing mothering experience from the first to the second litter - can determine subsequent vulnerability for PTSD-like behaviour. To assess the influence of maternal experience on different components of fear, we analysed the adult male offspring of two subsequent litters (offspring 1, 2) from the same parental C57BL/6NCrl (B6N) and C57BL/6JOla (B6JOla) mice for (i) their innate anxiety behaviour on a modified hole board and (ii) their vulnerability to develop long-lasting PTSD-like fear symptoms ("hyperarousal", contextually conditioned fear) following perception of an inescapable foot shock. Increasing maternal experience reduced the animals' innate fear on the modified hole board (more exploration, less inhibition), the acute stress reaction to the shock and - one month after trauma - the levels of hyperarousal-like behaviour in the PTSD-prone B6N strain. In contrast, both acquisition and extinction of contextually conditioned fear were increased in the second offspring, representing cognitive flexibility. A factor analysis showed that innate fear, "hyperarousal" and conditioned fear represent independent behavioural dimensions. In conclusion, the present study identifies maternal inexperience as a risk factor for the development of PTSD-like symptoms. This effect - occurring in inbred mice on an almost identical genetic background - emphasizes the impact of epigenetic factors in PTSD-like behaviour.

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.

The use of proton magnetic resonance spectroscopy in PTSD research--meta-analyses of findings and methodological review

Different neuroimaging techniques provided evidence for structural and functional brain alterations in posttraumatic stress disorder (PTSD). Due to technical improvements, especially concerning localization techniques and more reliable analysis methods, one technique, proton magnetic resonance spectroscopy ((1)H-MRS), has increasingly become of interest because it allows further insight into metabolic mechanisms that may contribute to these alterations. The aim of this article is, therefore, to review recent studies utilizing (1)H-MRS of the hippocampus and other brain structures in PTSD. Using meta-analytic methods, we attempted to answer the question if PTSD, as compared to different types of control samples, is accompanied by altered neurometabolite ratios and concentrations in the tissue of different brain regions. A second intent was to review methodological aspects to advise on a minimal standard for reliable results with respect to the application of (1)H-MRS in PTSD. Finally, we discussed the implications of the findings with respect to current PTSD models and future research.

Insular cortex involvement in declarative memory deficits in patients with post-traumatic stress disorder

BACKGROUND

Neuroimaging studies have proved that hippocampus relate to the deficient of memory in patients with post-traumatic stress disorder (PTSD). Many studies in healthy subjects also shown that insular cortex (IC) be involved in the declarative memory. This study was designed to investigate whether insular cortex is involved in declarative memory deficits in patients with PTSD.

METHODS

Twelve subjects with PTSD and 12 subjects without PTSD victims underwent functional magnetic resonance imaging and magnetic resonance imaging. All subjects performed encoding and retrieval memory tasks during the fMRI session. Voxel-based morphometry method was used to analyze gray-matter volume, and the Statistical Parametric Mapping (SPM2) was used to analyze activated brain areas when performing tasks.

RESULTS

Grey matter volume was significantly reduced bilaterally in the insular cortex of PTSD subjects than non-PTSD. PTSD group also had lower level of activation in insular cortex when performing word encoding and retrieval tasks than non-PTSD group.

CONCLUSION

The study provides evidence on structural and function abnormalities of the insular cortex in patients with PTSD. Reduced grey-matter volume in insular cortex may be associated with declarative memory deficits in patients with PTSD.