Psychometric properties of the late positive potential in combat-exposed veterans.

Trauma exposure is prevalent, associated with multiple forms of psychopathology, and thought to alter the neurobiological substrates of threat processing. The late positive potential (LPP) is an event-related potential (ERP) that may be a clinically useful probe of the neurobiology of threat processing. Despite evidence that combat-exposed veterans exhibit aberrant threat modulation of the LPP, no studies to date have tested the psychometric properties of the LPP in combat trauma-exposed, symptomatic veterans. The primary aim of the current study was to evaluate the reliability (internal consistency, retest reliability) and convergent validity of LPP modulation by threatening faces and scenes in two common tasks among combat-exposed veterans. Participants included 82 combat-exposed veterans who completed face-matching and emotion regulation tasks during EEG recording at baseline and twelve weeks. Internal consistencies of the early LPP time windows (<1000 ms) were acceptable in both tasks, whereas they were poor in late time windows (>1000 ms). Twelve-week retest reliabilities were fair for the early window LPPs to threatening scenes and fear faces, as well as in the late time window for fear faces. Reliabilities were better for individual condition compared to difference scores. Finally, LPPs modulated by threatening scenes and faces were unrelated. Together, these results suggest that the LPPs to threatening scenes and faces reflect distinct forms of threat processing in combat-exposed veterans, and their reliabilities for the early window indicate potential clinical utility in this population.

Concordance of Embedded Performance and Symptom Validity Tests and Associations with Mild Traumatic Brain Injury and Posttraumatic Stress Disorder among Post-9/11 Veterans.

OBJECTIVE: The present study explored both embedded symptom (SVT) and performance (PVT) validity test scores within a post-9/11 veteran sample to elucidate the degree to which there is concordance between validity indicators, as well as how frequently one SVT and four PVT indicators were failed in screened mild traumatic brain injury (mTBI) and diagnosed posttraumatic stress disorder (PTSD). METHOD: A total of 114 post-9/11 veterans were evaluated utilizing the Neurobehavioral Symptom Inventory (NSI) Validity-10, four embedded PVTs, mTBI screening, and a diagnostic interview for PTSD. RESULTS: While we found concordance between embedded PVTs and the NSI Validity-10 at select cutoffs (i.e., ≥13, ≥19), symptom and performance validity indicators were clinically dissociable in that only SVT significantly predicted diagnosed PTSD and screened mTBI. CONCLUSIONS: Dissociation between symptom and performance validity may be clinically useful when interpreting neuropsychological evaluation findings in post-9/11 veterans with a history of mTBI or PTSD.

Nonlinear relations between post-traumatic stress symptoms and electrocortical reactivity during emotional face processing in combat-exposed veterans.

Combat-related post-traumatic stress symptoms (PTSS) are prevalent among recently deployed veterans, making identification of biomarkers of PTSS in this population a public health priority. Given the link between threat processing neurobiology and PTSS, the threat-related late positive potential (LPP), an ERP reflective of attentional processing sensitive to emotion and its regulation, may have utility as a cost-effective biomarker. Existing PTSS/threat-related LPP findings are mixed, possibly due to variability in PTSS across samples, but this has never been explicitly tested. To address this gap, LPP amplitudes to angry, fearful, and happy emotional face stimuli were recorded among 81 combat-exposed veterans at a VA hospital. A quadratic relationship between self-reported PTSS and LPP amplitude modulation by angry faces emerged such that greater PTSS was related to a decreased LPP response to angry faces among veterans with subthreshold PTSD and an enhanced LPP response to angry faces among veterans with probable PTSD. These results suggest that prior mixed findings may be due to variability in PTSS severity. In addition, exploratory moderation analysis revealed that PTSS was positively associated with late LPP modulation for veterans reporting low cognitive reappraisal use and negatively associated with late LPP modulation for veterans reporting high cognitive reappraisal use. All results were specific to the 1,000-3,000 ms LPP time window. Thus, the functional nature of LPP modulation by direct threat cues may depend upon PTSS severity and/or related variables (e.g., cognitive reappraisal utilization).

The effects of smoking and smoking abstinence on verbal and visuospatial working memory capacity.

Several studies have examined the effects of smoking and abstaining from smoking on working memory (WM) but have yielded inconclusive findings. Thus, the authors used a repeated measures design to assess the effects of smoking and abstaining from smoking on both visuospatial and verbal WM capacity (WMC) using highly reliable, well-validated, and theoretically driven WM span tasks. Verbal n-back was also administered to examine its relationship to these complex WM span tasks and to compare this study's results with previous findings. Smokers (n=23) and nonsmokers (n=21) participated in 2 sessions separated by 1 week. During 1 session, smokers completed the WM tasks after abstaining from smoking for at least 12 hr, whereas in the other session smokers did not abstain from smoking and were tested immediately after smoking (all WM tasks were completed 45 min or less since last cigarette). Results indicated that smokers' verbal WM span was lower than nonsmokers' and was lower during the nonabstinent session compared with the abstinent session. Smokers' verbal n-back performance was also lower than nonsmokers', although there was no difference in verbal n-back performance between the smoking sessions. In contrast, there was no difference in visuospatial WM span between the smoking sessions or between smokers and nonsmokers. Taken together, these findings demonstrate that (a) smokers' verbal WM is lower than nonsmokers, (b) smokers' verbal WMC is lower during nonabstinence compared with abstinence, and (c) smoking exhibits differential effects on the different WM domains.

Differential impact of post-deployment stress and PTSD on neural reactivity to emotional stimuli in Iraq and Afghanistan veterans.

For many veterans returning from combat in Iraq and Afghanistan, the transition from military to civilian life is complicated by an array of postdeployment stressors. In addition to significant stress associated with reintegration after deployment, many returning veterans also contend with the added burden conferred by PTSD symptoms. While the relationship between PTSD symptoms and the neurobiological substrates of emotion dysregulation has begun to be studied, even less is known about the effects of postdeployment stress on neural function. In order to assess the relationship among a neural measure of attention to emotion (i.e. the late positive potential; LPP), PTSD symptoms and postdeployment stressors, EEG was recorded and examined in a linear mixed model of 81 OEF/OIF/OND veterans. Results revealed a main effect for postdeployment stressors such that increased postdeployment stress was associated with a relatively enhanced LPP across all emotion types. There was also a main effect for PTSD symptoms such that greater symptoms were related to a relatively blunted LPP across all emotion types. Findings may have important implications for understanding how both current stress and PTSD symptoms affect motivated attention as measured by the LPP. Moreover, this work highlights the need to consider the effects of current stress, in addition to PTSD symptoms, on the functioning of returning veterans.

Neural response to errors is associated with problematic alcohol use over time in combat-exposed returning veterans: An event-related potential study.

BACKGROUND: Currently, we do not have biomarkers to help identify individuals at-risk for chronic, problematic alcohol use, especially among veteran populations, who have notoriously high rates of alcohol use. One biomarker that may predict individuals at risk for chronic, problematic alcohol use is error-related brain activity. We examined longitudinal associations between the error-related negativity (ERN), an event-related potential observed following the commission of errors, and problematic alcohol use among U.S. military veterans returning from recent conflicts in Iraq and Afghanistan. METHODS: Forty-six military veterans, aged 18-55 years, completed a well-validated flanker task known to elicit the ERN at baseline. Problematic alcohol use and other clinically relevant variables were assessed at baseline, 3-, 6-, 9-, 12-, 15-, 18-, 21-months, and 2 years. RESULTS: Results indicated that the ERN magnitude was associated with problematic alcohol use over time, even after controlling for relevant clinical variables. Specifically, veterans with a smaller ERN magnitude evidenced a decline in problematic alcohol use over time, while veterans with a larger ERN magnitude had no change in their problematic alcohol use across the follow-up. In addition, exploratory analyses found that treatment engagement during the study did not moderate these relationships. CONCLUSIONS: Our findings provide preliminary evidence that ERN can be used as a predictor of problematic alcohol use over time. Therefore, neural response to errors could help to identify individuals at risk for continued problematic alcohol use for intervention efforts and suggests that error processing may be an important therapeutic target within Alcohol Use Disorder intervention efforts.

Cognitive reappraisal moderates the relationship between PTSD symptoms and alcohol use over time in post-9/11 U.S. military veterans.

BACKGROUND: Rates of comorbid alcohol use disorder (AUD) and posttraumatic stress disorder (PTSD) are increasing among post-9/11 veterans, and emotion regulation problems have been identified as a feature of both disorders. However, no studies to date have explored how individual differences in emotion regulation may moderate the relationship between PTSD symptoms and alcohol use. We evaluated how two core emotion regulation strategies - one adaptive (i.e., cognitive reappraisal) and one maladaptive (i.e., expressive suppression) are related to PTSD symptoms and alcohol use over one-year. METHODS: A total of 71 post-9/11 veterans (12 female, 59 male) completed a baseline screening and at least two follow-up assessments over the course of 12 months which included measures of emotion regulation, PTSD symptoms, and alcohol use. A mixed growth model was utilized to determine if changes in PTSD symptoms covaried with alcohol use over time and whether this relation was moderated by frequency of use of emotion regulation strategies. RESULTS: In general, higher PTSD symptoms were significantly associated with greater alcohol use, but cognitive reappraisal moderated this relationship. Specifically, at low cognitive reappraisal, greater PTSD symptoms were associated with greater alcohol use. At high cognitive reappraisal, there was no significant association between PTSD symptoms and alcohol use. CONCLUSIONS: Findings from the present study suggest that baseline individual differences in cognitive reappraisal influence the relation between PTSD symptoms and alcohol use. For post-9/11 veterans, high levels of cognitive reappraisal may serve as a protective factor against ongoing alcohol use.

Impact of PTSD on post-concussive symptoms, neuropsychological functioning, and pain in post-9/11 veterans with mild traumatic brain injury.

Prior work suggested that post-traumatic stress disorder (PTSD) worsens post-concussive symptoms (PCS), neuropsychological functioning, and pain-related outcomes in post-9/11 veterans. However, the impact of PTSD in the context of mild traumatic brain injury (mTBI) is not entirely clear. We evaluated possible differences among veterans with deployment-related mTBI with and without PTSD, and a comparison group. We hypothesized that veterans with comorbid mTBI and PTSD would report more PCS, perform worse on neuropsychological tasks, and report greater pain intensity and maladaptive pain coping relative to those without PTSD. Ninety (15 female, 75 male) post-9/11 veterans completed measures of psychiatric functioning, PCS, deployment-related mTBI, pain intensity, pain coping, and a brief neuropsychological evaluation. Veterans with comorbid mTBI and PTSD reported significantly higher PCS across domains, and greater pain intensity and maladaptive coping. They also performed more poorly on measures of recall, but not on measures of attention, encoding, or executive functioning. Findings suggest that PTSD results in greater PCS in the context of mTBI, and is associated with greater pain catastrophizing, worse recall, greater pain intensity, and greater illness-focused coping than in mTBI alone. PCS symptoms, recall, and pain coping may be of clinical importance for post-9/11 veterans with the "polytrauma triad."

Neural indices of emotional reactivity and regulation predict course of PTSD symptoms in combat-exposed veterans.

After diagnosis, veterans with posttraumatic stress disorder (PTSD) display significant variability in the natural course of illness (Bonanno et al., 2012)). Cross-sectional work reveals that abnormal neural response during emotion reactivity-measured using the late positive potential (LPP)-correlates with PTSD symptom severity; however, whether the LPP during emotional reactivity and regulation predicts symptoms over time is unknown. The current study examined the LPP during emotion reactivity and regulation as predictors of PTSD symptoms over one year in OEF/OIF/OND combat-exposed veterans. At baseline, participants completed an Emotion Regulation Task (ERT) during electroencephalogram recording. The Clinician Administered PTSD Scale (CAPS) was completed at baseline (N=86), 6-months (N=54) and 1-year (N=49) later. During ERT, participants viewed negative pictures; partway through they were instructed to "reappraise" (i.e., reduce negative affect/regulate) or "look" (i.e., passively react). Change in LPP during emotional reactivity (ΔLPP-E) and reappraisal (ΔLPP-R) were calculated and used in multilevel mixed modeling to predict CAPS over time. Findings demonstrated that deficiency in reappraisal (ΔLPP-R) predicted more overall symptoms over time, while greater neural responses to emotion (ΔLPP-E) and greater change in neural response as a function of reappraisal (ΔLPP-R) predicted a decline in avoidance symptoms over time. Together, results support the utility of neural markers of emotional reactivity and regulation as predictors of PTSD symptoms-and change in symptoms-across one year.

Individual differences in combat experiences and error-related brain activity in OEF/OIF/OND veterans.

Increased error-related negativity (ERN) has been implicated in the pathophysiology of multiple forms of psychopathology. Although there is increasing evidence that the ERN can be shaped by environment and experience, no studies to date have examined this question in a clinical sample. In the current study, we examined the influence of combat exposure on the ERN using electroencephalogram (EEG) in a sample of military veterans with a high prevalence of psychopathology. Participants included sixty-seven U.S. military veterans from Operations Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND). The degree of combat exposure was assessed using the Deployment Risk and Resilience Inventory-2 (DRRI-2) and Combat Exposure Scale (CES). A well-validated flanker task was used to elicit the ERN during continuous EEG recording. Results revealed that veterans who reported experiencing greater combat exposure exhibited a more enhanced ERN, even when adjusting for broad anxiety and posttraumatic stress disorder (PTSD) symptoms. The association between combat exposure and ERN was not moderated by PTSD symptom severity. The current study demonstrates that greater combat exposure is associated with a more enhanced ERN among OEF/OIF/OND veterans. This enhanced ERN may be one mechanism that places veterans at greater risk for developing psychiatric disorders following exposure to combat. Future longitudinal studies are needed to directly test whether the ERN mediates the relation between level of combat exposure and the development of internalizing disorders.

The acute effects of nicotine on positive and negative affect in adolescent smokers.

Although adolescent cigarette smoking remains a critical public health concern, little is known about the reinforcing mechanisms governing smoking in this vulnerable population. To assess predictions derived from both positive and negative reinforcement models of drug use, the authors measured the acute effects of nicotine, as administered via tobacco cigarettes, on both positive and negative affect in a group of 15- to 18-year-old smokers. A matched group of nonsmokers served as a comparison group. Findings revealed that whereas adolescents who smoked a cigarette experienced reductions in both positive and negative affect, the observed reductions in negative affect were moderated by nicotine content of the cigarette (high yield vs. denicotinized), level of nicotine dependence, level of baseline craving, and smoking expectancies pertinent to negative affect regulation. Nonsmokers experienced no change in affect over the 10-min assessment period, and no interaction effects were observed for positive affect. Overall, the findings conform to a negative reinforcement model of nicotine effects and strongly suggest that, even among young light smokers, nicotine dependence and resultant withdrawal symptomatology may serve as motivating factors governing smoking behavior.

An electrocortical investigation of emotional face processing in military-related posttraumatic stress disorder.

PTSD is a disorder of emotion dysregulation. Although much work has intended to elucidate the neural underpinnings of the disorder, much remains unknown about the neurobiological substrates of emotion dysregulation in PTSD. In order to assess the relationship between a neural measure of attention to emotion (i.e. the late positive potential; LPP) and PTSD symptoms, EEG was recorded and examined as a potential predictor of military-related PTSD symptoms in a sample of 73 OEF/OIF/OND veterans. Results revealed that higher PTSD symptoms were related to an attenuated LPP response to angry facial expressions. This finding was not observed for happy or fearful faces. The current study provides initial evidence that, in a relatively young, mostly male sample of OEF/OIF/OND veterans, hyporeactivity to angry faces at the neural level may provide phenotypic data to characterize individual differences in PTSD symptom severity. This work may assist in future studies that seek to examine useful psychophysiologic targets for treatment and early interventions.

PTSD symptoms are associated with visual retrieval performance in OEF/OIF/OND veterans.

Posttraumatic stress disorder (PTSD) is associated with poorer performance on neuropsychological tests in veterans. However, prior studies have generally compared individuals with PTSD to control groups, often excluding individuals with moderate symptoms. The present study evaluated neuropsychological performance among OEF/OIF/OND veterans as a function of overall PTSD severity, while also exploring potential associations between cognitive performance and PTSD symptom clusters. Using a brief neuropsychological battery, clinical interviews, and self-report instruments, we evaluated neuropsychological and psychiatric functioning in 90 OEF/OIF/OND veterans. When controlling for the effects of premorbid intellectual functioning and combat exposure, higher PTSD severity predicted worse visual retrieval performance, but not attention, verbal retrieval, visual learning, or executive functioning performance. A trend was observed where higher PTSD symptoms predicted worse verbal learning performance. All PTSD symptom clusters were associated with visual retrieval performance within the full sample. Avoidance and numbing symptoms were associated with verbal learning in the full sample. Findings suggest that among OEF/OIF/OND veterans with a range of PTSD symptoms, the assessment of visual memory may have implications for clinical practice.

Affective and cognitive correlates of PTSD: Electrocortical processing of threat and perseverative errors on the WCST in combat-related PTSD.

PTSD is characterized by both affective and cognitive dysfunction. Affectively, PTSD is associated with both heightened emotional reactivity and disengagement. Cognitively, perseverative thinking is a core feature of the disorder. In order to assess the interactive effects of affective and cognitive correlates of PTSD symptoms, 47 OEF/OIF/OND veterans completed an emotional faces matching task while EEG (i.e., late positive potential; LPP) was recorded, and separately completed the Wisconsin Card Sorting Test (WCST) to assess perseverative errors. There was no relationship between PTSD symptoms and either perseverative errors or EEG reactivity to faces. However, an interaction was found such that high perseverative errors on the WCST and a relatively enhanced LPP to angry faces was associated with greater PTSD symptoms, while low errors on the WCST and a relatively blunted LPP to angry faces also related to greater PTSD symptoms. These findings suggest that emotion-cognition interactions are important for understanding PTSD, and that distinct emotion-cognition constellations interact with symptoms.

An electrocortical investigation of voluntary emotion regulation in combat-related posttraumatic stress disorder.

Posttraumatic stress disorder (PTSD) - a debilitating disorder characterized by severe deficits in emotion regulation - is prevalent among U.S. military veterans. Research into the pathophysiology of PTSD has focused primarily on emotional reactivity, showing evidence of heightened neural response during negative affect provocation. By comparison, studies of brain functioning during the voluntary regulation of negative affect are limited. In the current study, combat-exposed U.S. military veterans with (n=25) and without (n=25) PTSD performed an emotion regulation task during electroencephalographic (EEG) recording. The late positive potential (LPP) was used as a measure of sustained attention toward, and processing of, negative and neutral pictures, and was scored prior to and after instructions to either maintain or down-regulate emotional response using the strategy of cognitive reappraisal. Results showed that groups did not differ in picture-elicited LPP amplitude either prior to or during cognitive reappraisal; reappraisal reduced the LPP in both groups over time. Time-dependent increases in LPP amplitude as a function of emotional reactivity maintenance were evident in the non-PTSD group only. This latter finding may signal PTSD-related deficits in sustained engagement with emotion-processing over the course of several seconds.

Impact of alcohol use disorder comorbidity on defensive reactivity to errors in veterans with posttraumatic stress disorder.

Converging lines of evidence suggest that individuals with comorbid posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) may be characterized by heightened defensive reactivity, which serves to maintain drinking behaviors and anxiety/hyperarousal symptoms. However, it is important to note that very few studies have directly tested whether individuals with PTSD and AUD exhibit greater defensive reactivity compared with individuals with PTSD without AUD. Therefore, the aim of the current study was to test this emerging hypothesis by examining individual differences in error-related negativity (ERN), an event-related component that is larger among anxious individuals and is thought to reflect defensive reactivity to errors. Participants were 66 military veterans who completed a well-validated flanker task known to robustly elicit the ERN. Veterans were comprised of 3 groups: controls (i.e., no PTSD or AUD), PTSD-AUD (i.e., current PTSD but no AUD), and PTSD + AUD (i.e., current comorbid PTSD and AUD). Results indicated that individuals with PTSD and controls generally did not differ in ERN amplitude. However, among individuals with PTSD, those with comorbid AUD had significantly larger ERNs than those without AUD. These findings suggest that PTSD + AUD is a neurobiologically unique subtype of PTSD, and the comorbidity of AUD may enhance defensive reactivity to errors in individuals with PTSD. (PsycINFO Database Record

The effects of smoking on selective attention as measured by startle reflex, skin conductance, and heart rate responses to auditory startle stimuli.

The present study examined the effects of cigarette smoking on attentional processing by measuring nondeprived smokers' (n=39), minimally deprived smokers' (n=36), and nonsmokers' (n=34) startle eyeblink reflex, heart rate, and skin conductance responses (SCR) to acoustic startle stimuli (105 dB) during directed attention tasks. Whereas smokers demonstrated smaller startle responses than nonsmokers during a directed attention visual task, no difference in startle response magnitude emerged between the two smoking groups, nor did we observe an effect of smoking on SCR or heart rate response to the startle stimuli. Our findings suggest that smokers differ from nonsmokers in their selective attention abilities and that smoking does not enhance minimally deprived smokers' selective attention.

The separate and combined effects of nicotine and alcohol on working memory capacity in nonabstinent smokers.

Research indicates that nicotine and alcohol are often used on the same occasion. However, the reasons for their concurrent use are not well understood. We hypothesized that one reason smokers use tobacco when they drink alcohol is to compensate for alcohol's negative effects on processing capacity with nicotine's enhancement of processing capacity. As such, the present study tested this theory by using an independent groups design to examine the separate and combined acute effects of alcohol and nicotine on working memory (WM) capacity. Nonabstinent daily smokers (n = 127) performed the counting span task (CSPAN) after consuming either an alcohol (men: 0.8 g/kg; women: 0.7 g/kg) or placebo beverage and smoking either nicotinized (1.14 mg nicotine, 15.9 mg tar) or denicotinized (.06 mg nicotine, 17.9 mg tar) cigarettes. Analyses revealed that smokers who smoked the nicotinized cigarettes performed significantly worse on the CSPAN task than smokers who smoked the denicotinized cigarettes. Although there was no main effect of alcohol on WM performance, women exhibited better WM performance than men after consuming alcohol whereas men performed better than women on the WM task after consuming the placebo beverage. Findings also revealed no interaction between the two substances on WM performance. Taken together, results suggest that nicotine impairs nonabstinent smokers' verbal WM capacity and that gender moderates the effects of alcohol on WM. Furthermore, the present findings failed to support the notion that nicotine compensates for alcohol-related decrements in working memory capacity.

Smoking topography in response to denicotinized and high-yield nicotine cigarettes in adolescent smokers.

PURPOSE: The objective of this study was to explore the smoking topography of adolescent smokers. It is well established that the majority of adult nicotine-dependent smokers began smoking as adolescents. Whereas recent advances have been made with respect to identification of factors that predispose to nicotine dependence, very little is known about the actual smoking behavior (e.g., topography) of adolescent smokers, or its relationship to nicotine dependence. Correspondingly, the extent to which adolescent smokers smoke to obtain nicotine is also unknown. METHODS: In the present study, we assessed several topographical indices of smoking (e.g., puff volume, puff number) in a sample of 35 light, adolescent smokers. Moreover, we examined whether smoking behavior is different in response to smoking a denicotinized relative to a high-yield, nicotine cigarette. RESULTS: All participants evidenced a significant increase in expired air carbon monoxide after the smoking of a cigarette. Results of independent-sample t-tests revealed that adolescents who smoked a low-yield nicotine cigarette took significantly more puffs per cigarette than did those who smoked a high-yield cigarette. CONCLUSIONS: These findings suggest that adolescent smokers do titrate their nicotine intake in response to smoking denicotinized cigarettes, but do so not by taking larger puffs or smoking more quickly, but by simply taking more puffs per cigarette. Implications of the findings and future directions for this type of research with adolescents are discussed.