Neuropsychological Performance in Gulf War Era Veterans: Traumatic Stress Symptomatology and Exposure to Chemical–Biological Warfare Agents

Because complaints of diminished concentration and memory are among the most common health symptoms reported by Gulf War (GW) veterans with unexplained illnesses, this study investigated neuropsychological functions among GW veterans and controls. Relationships between neuropsychological performance, severity of posttraumatic stress disorder (PTSD) symptomatology, and exposure to chemical–biological warfare agents (CBW) were assessed. Participants were 225 veterans recruited from three cohorts: GW-deployed veterans from Ft. Devens, MA ( n = 141) and New Orleans, LA (n = 37), and Germany-deployed veterans from a Maine National Guard unit (n = 47). A comprehensive evaluation was completed. Severity of subclinical PTSD symptomatology was significantly related to scores on specific neuropsychological tests. PTSD symptom severity in GW-deployed veterans was found to be greater and associated with a broader range of neuropsychological deficits than in Germany-deployed veterans. PTSD severity was associated with lower performance on a range of neuropsychological tasks, whereas CBW exposure contributed to performance deficits on specific cognitive tasks.     

Neuropsychological Performance in Gulf War Era Veterans: Neuropsychological Symptom Reporting

Relationships between broad-based health symptoms and neuropsychological performance have been investigated previously in Gulf War (GW) veterans. However, very little has been done to assess relationships between severity of neuropsychological symptom complaints and performance on objective neuropsychological tests. In this study, relationships between level of self-reported neuropsychological symptom severity and objective neuropsychological performance measures were investigated. Participants included 240 veterans from three GW-era cohorts: GW-deployed veterans recruited from Ft. Devens, MA, (n = 142) and from New Orleans, LA (n = 51), and veterans deployed to Germany from a Maine National Guard unit (n = 47). Findings suggest that level of subjective neuropsychological complaints was associated primarily with mood symptoms in GW-era veterans. Among GW-deployed troops, high neuropsychological symptom reporters endorsed more tension, fatigue, and confusion and less vigor than those reporting fewer cognitive complaints. Current findings emphasize the importance of independent assessment of subjective symptoms and objective neuropsychological performance.     

Performance on the Test of Memory Malingering in children with neurological conditions

Despite increasing interest in the use of performance validity tests with youth, relatively little is known about how children and adolescents with neurological diagnoses perform on these measures. The purpose of this study was to examine performance on the Test of Memory Malingering (TOMM) in a general pediatric neurologic sample. Data were obtained from 266 consecutive patients (mean age = 13.0, SD = 3.7, range = 5–18) referred for a neuropsychological assessment in a tertiary care pediatric hospital. As part of a broader neuropsychological battery, patients were administered the TOMM. In this sample, 94% of children passed the TOMM. Pass rate was 87% for 5–7 year-olds but was ≥ 90% for all other ages. Children with a history of stroke had the lowest pass rate (86%), with other diagnostic groups scoring ≥ 90%, including epilepsy, traumatic brain injury, and hydrocephalus. Lower TOMM performance was related to slower processing speed and weaker memory performance. The results support using the TOMM with children and adolescents who have neurological diagnoses. Caution may still be warranted when interpreting scores in those who are younger and/or who have more significant cognitive difficulty.     

A data-driven approach to neuropsychological features in isolated REM behaviour disorder: A latent class analysis

Recent evidence demonstrated that neuropsychological assessment may be considered a valid marker of neurodegeneration in idiopathic REM sleep behaviour disorder (iRBD). However, little is known about the possible neuropsychological heterogeneity within the iRBD population. This retrospective study aimed to identify and describe different neuropsychological phenotypes in iRBD patients by means of a data-driven approach using latent class analysis. A total of 289 iRBD patients underwent a neuropsychological assessment evaluating cognitive domains: global cognition, language, short- and long-term memory, executive functions and visuospatial abilities. The presence of mild cognitive impairment (MCI) was also assessed. Latent class analysis was carried out to identify iRBD subtypes according to neuropsychological scores. The most parsimonious model identified three latent classes. Groups were labelled as follows: Class 2 “severely impaired” (n = 83/289): mean pathological scores in different tests, a high percentage of MCI multiple-domain and impairment in all neuropsychological domains. Class 1 “moderately impaired” (n = 44/289): mean neuropsychological score within the normal value, a high percentage of MCI (high risk to phenoconversion) and great impairment in the visuospatial domain. Class 3 “slightly impaired” (n = 162/289): no deficit worthy of attention except for short- and long-term memory. Our results suggest three different clinical phenotypes within the iRBD population. These findings may be relevant in the future for predicting the clinical trajectories of phenoconversion in iRBD.     

Impaired Consonant Trigrams Test (CTT) performance relates to everyday working memory difficulties in children with Autism Spectrum Disorders

Individuals with Autism Spectrum Disorders (ASD) often struggle with complex tasks, such as those requiring divided attention (simultaneously completing two independent tasks) that also place high demands on working memory. Prior research shows that divided attention is impaired in adults and children with ASD and is related to ASD and comorbid attention deficit/hyperactivity disorder (ADHD) symptoms, but the impact on everyday functioning is unclear. Because ADHD symptoms are associated with poor divided attention and working memory performance in children with ASD, we also examined ADHD symptoms as moderators of divided attention performance. We examined performance on the Consonant Trigrams Test (CTT) between high-functioning 8- to 13-year-olds with ASD (n?=?28) and typically developing controls (n?=?18) matched on age and IQ. In the ASD group, we also correlated performance with ADHD symptoms and behavior ratings of everyday working memory. CTT performance in children with ASD was significantly worse than in matched controls. A significant correlation between CTT performance and everyday working memory was observed, but CTT performance was not related to comorbid ADHD symptoms in the ASD group. Divided attention with high working-memory demands is a relative weakness in children with high-functioning ASD; this weakness relates to everyday functioning, and it is independent from ADHD symptoms. That ADHD symptoms are not associated with divided attention performance is inconsistent with one prior investigation, which likely results from using different divided attention tasks in the two studies.     

Behavioral,psychological, and historical correlates of MacAndrew scale scores among male alcoholics

Male alcoholic veterans (N=194) were divided into four groups on the basis of their scores on the MacAndrew scale (MAC) of the Minnesota Multiphasic Personality Inventory (MMPI) and compared on psychological and sociodemographic measures and self-reported alcohol, drug, and legal histories. Nineteen subjects scored in the nonalcoholic (NA) range of the MAC (i.e., false negatives, MAC23). Remaining subjects, scoring in the alcoholic range of the MAC, were divided into thirds by MAC scores (lowest third, L-MAC=24–28,n=53; middle third, M-MAC=29–31,n=63; highest third, H-MAC>31,n=59). Groups did not differ on age, any important sociodemographic variables, or scores on the Profile of Mood States, State-Trait Anxiety Inventory, Symptom Checklist-90, or Rod and Frame Test. Significant group differences were obtained on several MMPI scales. Lower MAC scores were associated with higher scores onL, K, D, andR, and lower scores onMa. There was also a tendency for subjects with lower MAC scores to score higher onSi. NA subjects began drinking and heavy drinking later than other subjects, although groups did not differ on duration, quantity, or frequency of drinking. Subjects with higher MAC scores more often reported drinking in bars, drinking liquor straight, alcohol-related job disruptions, and previous use of marijuana, hallucinogens, and barbiturates. Subjects with higher MAC scores had more often been arrested, convicted, fined, and jailed for alcohol-related offenses but not for other offenses. Results are examined with respect to MacAndrew's distinction between primary and secondary alcoholics and with respect to the possible relations of MAC to important person variables such as sensation seeking.The authors wish to thank Craig MacAndrew for his helpful critical reading of an early draft of this paper. We also thank Theresa Hilliard, Shirley White, Vicki Brumbelow, and Pam Thompson for editorial assistance and Audrey Jefferson for help with data preparation.     

Event‐based prospective memory and obsessive–compulsive disorder intrusive obsessional thoughts

Recent studies have found poorer prospective remembering among students selected for elevated obsessive–compulsive disorder (OCD) checking and washing. However, as prospective memory performance also requires retrospective remembering, it is not clear from earlier work whether deficits in prospective memory in samples with OCD symptomatology are due to problems with prospective remembering, or to retrospective memory failures that result in poorer performance on prospective memory tasks. The present study examines performance on matched prospective and retrospective memory tasks among students selected for high (n = 48) and low (n = 44) scores on the Obsessive–Compulsive Inventory‐Revised Obsession subscale. Significant differences between the groups were found in prospective memory (regardless of whether the word was neutral or harm/danger‐related), but not retrospective memory. The findings are consistent with the prediction that obsessional thoughts that occupy working memory capacity would have a deleterious effect on a resource‐demanding prospective memory task. An additional finding was that there were no group differences in self‐reported complaints of problems with prospective memory.     

Individual neuropsychological profiles at age 5½ years in children born preterm in relation to medical risk factors

Follow-up studies of preterm children have reported a range of cognitive deficits, particularly in executive functions, visuospatial abilities, and learning. However, few researchers have adopted a person-oriented approach, exploring individual neuropsychological profiles. The aim of this study was to identify typical neuropsychological profiles among preterm children and control children, respectively. A second aim was to investigate if neuropsychological profiles at age 5½ might be associated with perinatal medical risk factors. As part of the longitudinal Stockholm Neonatal Project, NEPSY for 4- to 7-year-old children (Korkman, 1990 Korkman, M. 1990. NEPSY, Neuropsychological Assesment 4–7 years: Swedish Version, Stockholm, , Sweden: Psykologiförlaget AB.  [Google Scholar]), WPPSI-R, and Movement ABC were administered at age 5½ years to 145 preterm (mean gestational age 28 weeks) and 117 control children born at term. For the present study, the NEPSY results of each child were transformed into summary z scores for each of 5 neuropsychological domains: attention, memory, sensory-motor, verbal, and visuospatial functions. Subsequently, Ward's cluster analysis was performed for the preterm and control groups separately, identifying 5 neuropsychological profiles in both groups explaining around 56% and 57% of the variance, respectively. Overall, preterm children had lower neuropsychological results but also more diverging profiles compared to controls. The variability in outcome could not be sufficiently explained by birth weight, gestational age, or medical risks. The results suggest that prematurity interacts dynamically with genetic, medical, and environmental factors in neuropsychological development.     

Hypertension and cognitive function

Previous research indicates that blood pressure may impact a variety of cognitive functions, including short-term memory, abstract reasoning, visual-spatial abilities, and attention (Boller, Vrtunski, Mack, & Kim, 1977; Elias, Robbins, Schultz, & Pierce, 1990; Franceschi, Tancredi, Smirne, Mercinelli, & Canal, 1982; Mazzucchiet al., 1986). However, studies which have assessed the cognitive functioning of hypertensive adults have offered conflicting results, particularly when hypertension levels were in the mild range (e.g., Bolleret al., 1977; Eliaset al., 1990; Elias, Wolf, D'Agostino, Cobb, & White, 1993; Farmeret al., 1987, 1990; Franceschiet al., 1982; Pérez-Stable, Coates, Halliday, Gardiner, & Hauck, 1992; Schmidtet al., 1991; Waldstein, Ryan, Manuck, Parkinson, & Bromet, 1991). A number of factors may contribute to the inconsistent findings in this area. Researchers have employed a wide range of neuropsychological instruments to assess varying domains of cognitive function. Sample sizes in some studies have been too small to ensure sufficient power. Finally, studies have employed varying methodological control over potential confounding factors such as concurrent medical conditions, alcohol abuse, psychiatric disorders, or antihypertensive medication. This study compared male veterans with blood pressures in the mildly hypertensive range (n=166) to normotensive veterans (n=176) on neuropsychological measures of verbal fluency, visual-spatial ability, verbal and visual memory, dexterity, attention, and executive functions. Results revealed that, after controlling for differences in education and income, there was no relationship between mild hypertension and combined measures of cognitive performance. The present findings suggest that mild hypertension alone has little effect on cognitive function in adults.     

Individual differences in media multitasking and performance on the <Emphasis Type="Italic">n</Emphasis>-back

A number of studies have recently examined the link between individual differences in media multitasking (using the MMI) and performance on working memory paradigms. However, these studies have yielded mixed results. Here we examine the relation between media multitasking and one particular working memory paradigm—the n-back (2- and 3-back)—improving upon previous research by (a) treating media multitasking as a continuous variable and adopting a correlational approach as well as (b) using a large sample of participants. First, we found that higher scores on the MMI were associated with a greater proportion of omitted trials on both the 2-back and 3-back, indicating that heavier media multitaskers were more disengaged during the n-back. In line with such a claim, heavier media multitaskers were also more likely to confess to responding randomly during various portions of the experiment, and to report media multitasking during the experiment itself. Importantly, when controlling for the relation between MMI scores and omissions, higher scores on the MMI were associated with an increase in false alarms, but not with a change in hits. These findings refine the extant literature on media multitasking and working memory performance (specifically, performance on the n-back), and suggest that media multitasking may be related to the propensity to disengage from ongoing tasks.     

Distinctiveness and serial position functions in implicit memory

Serial position functions, with their characteristic primacy and recency effects, are ubiquitous in episodic memory tasks, and have also been observed in tasks tapping semantic memory. However, only one experiment, [Raanaas, R. K., & Magnussen, S. (2006a). Serial position effects in implicit memory. European Journal of Cognitive Psychology, 18, 398–414. doi:10.1080/09541440500162065], has demonstrated primacy and recency effects in implicit memory using an indirect memory test. In Experiment 1, we replicate this finding and in Experiment 2, we confirm a prediction that holds only if the serial position function observed in Experiment 1 was a “real” serial position function. These results confirm the presence of serial position functions in implicit memory and also support a general prediction of the relative distinctiveness principle that serial position functions should obtain whenever a set of items are ordered along a relevant dimension.     

Performance on the test of memory malingering in a mixed pediatric sample.

Performance on the Test of Memory Malingering (TOMM) was evaluated in a sample of 100 consecutively referred 6 to 16-year-old children with a wide range of clinical diagnoses. In the complete sample, 97 children met actuarially defined criteria for sufficient effort on the TOMM. Two children were correctly identified as providing suboptimal effort and only one case was a possible false positive. Performance on the second trial of the TOMM did not vary with gender, ethnicity, parental occupation, performance on an independent memory test, or length of coma. Although younger children tended to be somewhat less efficient on the TOMM than older children, more than 90% of children in the 6-8 years range met criteria originally developed for adults for sufficient effort on the TOMM. It is concluded that the TOMM is a potentially useful measure of effort in the clinical neuropsychological evaluation of school-age children.     

Postnatal exposure to methyl mercury and neuropsychological development in 7-year-old urban inner-city children exposed to lead in the United States

Background: The most common route for general population exposure to methyl mercury (MeHg) is fish consumption. Recommendations to pregnant women about consuming fish contaminated with MeHg are also applied to children, but there are few studies available about the effects of low-level postnatal MeHg exposure in them.

Objectives: To investigate the association between postnatal methyl mercury exposure and neuropsychological development in a study of children also exposed to lead, both measured at 7 years.

Methods: We measured MeHg concentrations in blood samples from the Treatment of Lead-Exposed Children (TLC) trial in which 780 children with elevated concentrations of lead in blood were followed with neuropsychological tests from ages 12–33 months through 7 years. Here we examine blood MeHg concentration and neuropsychological test scores, both measured at age 7 years. We used a maximum likelihood method to estimate geometric mean MeHg concentration and generalized linear regression models to analyze MeHg and neuropsychological test scores.

Results: Geometric mean MeHg concentration was 0.56 (95% confidence interval: 0.52, 0.59) μg/L. A 1 μg/L increase in MeHg was associated with a 2.1 (95% confidence interval: 0.4, 3.8) point increase in Full-Scale IQ and 0.2 (95% confidence interval: 0.02, 0.4) point increase in Learning Slopeindex T-score on a test of verbal memory.

Conclusions: Our results suggest that the relatively low MeHg exposure in US school-aged children from this population has no detectable adverse effect on neuropsychological development. The positive associations observed between MeHg and neurodevelopment may indirectly reflect consumption of beneficial polyunsaturated fatty acids from seafood.     

PERFORMANCE ON THE TEST OF MEMORY MALINGERING IN A MIXED PEDIATRIC SAMPLE

Performance on the Test of Memory Malingering (TOMM) was evaluated in a sample of 100 consecutively referred 6 to 16–year-old children with a wide range of clinical diagnoses. In the complete sample, 97 children met actuarially defined criteria for sufficient effort on the TOMM. Two children were correctly identified as providing suboptimal effort and only one case was a possible false positive. Performance on the second trial of the TOMM did not vary with gender, ethnicity, parental occupation, performance on an independent memory test, or length of coma. Although younger children tended to be somewhat less efficient on the TOMM than older children, more than 90% of children in the 6-8 years range met criteria originally developed for adults for sufficient effort on the TOMM. It is concluded that the TOMM is a potentially useful measure of effort in the clinical neuropsychological evaluation of school-age children.     

Cross-validation of a minnesota multiphasic personality inventory (MMPI) subscale for the assessment of combat-related post-traumatic stress disorder

We have examined the Minnesota Multiphasic Personality Inventory (MMPI) scores of 80 carefully diagnosed veterans with post-traumatic stress disorder (PTSD) in an attempt to cross-validate the PTSD subscale and three-point MMPI code of Keane, Malloy, and Fairbank (1984). In general, although we replicated Keane and co-workers'cutoff scores, our hit rates were slightly lower than those reported originally.This research was supported in part by NIMH Grant MH-37839 to Dr. Kolb.     

Working memory training improvements and gains in non-trained cognitive tasks in young and older adults

Previous studies on working memory training have indicated that transfer to non-trained tasks of other cognitive domains may be possible. The aim of this study is to compare working memory training and transfer effects between younger and older adults (n = 60). A novel approach to adaptive n-back training (12 sessions) was implemented by varying the working memory load and the presentation speed. All participants completed a neuropsychological battery of tests before and after the training. On average, younger training participants achieved difficulty level 12 after training, while older training participants only reached difficulty level 5. In younger participants, transfer to Verbal Fluency and Digit Symbol Substitution test was found. In older participants, we observed a transfer to Digit Span Forward, CERAD Delayed Recall, and Digit Symbol Substitution test. Results suggest that working memory training may be a beneficial intervention for maintaining and improving cognitive functioning in old age.     

Clarifying Heterogeneity of Daytime and Nighttime Symptoms of Posttraumatic Stress in Combat Veterans With Insomnia

Daytime and nighttime symptoms of posttraumatic stress disorder (PTSD) are common among combat veterans and military service members. However, there is a great deal of heterogeneity in how symptoms are expressed. Clarifying the heterogeneity of daytime and nighttime PTSD symptoms through exploratory clustering may generate hypotheses regarding ways to optimally match evidence-based treatments to PTSD symptom profiles. We used mixture modeling to reveal clusters based on 6 daytime and nighttime symptoms of 154 combat veterans with insomnia and varying levels of PTSD symptoms. Three clusters with increasing symptom severity were identified (n1 = 50, n2 = 70, n3 = 34). These results suggest that, among veterans with insomnia, PTSD symptoms tend to exist on a continuum of severity, rather than as a categorical PTSD diagnosis. Hypotheses regarding possible targeted treatment strategies for veterans within each identified cluster, as well as ways to generalize these methods to other groups within the military, are discussed.     

MMPI-2 Assessment of Varying Levels of Posttraumatic Stress in Vietnam Combat Veterans

The effectiveness of the MMPI-2 in the detection of posttraumatic stress (PTS) symptomatology was investigated. Forty-nine veterans at a VA posttraumatic stress clinic were evaluated for PTS symptomatology according to DSM-III-R criteria. The ability of the MMPI-2 to differentiate between Vietnam combat veterans (VCV) who met DSM-III-R criteria for posttraumatic stress disorder (PTSD; N = 36) and those who reported varying levels of posttraumatic stress symptoms (PTSS; N = 13) was examined. Overall, the MMPI-2 was effective in differentiating between the two groups of veterans. Of the 15 MMPI-2 scales used to evaluate PTS symptomatology, 12 significantly differentiated veterans with PTSD from those with PTSS. Diagnostic efficiency statistics for the MMPI-2 PTSD scales (PS and PK) were calculated at four cutoff points (T 65, 70, 75, and 80). The PS Scale was the most robust and effective index in differentiating between veterans with PTSD and those with PTSS. Implications for the assessment of varying degrees of PTS are discussed.     

Cognitive Functioning in Treatment-Seeking Gulf War Veterans: Pyridostigmine Bromide Use and PTSD

Gulf War (GW) deployed veterans have reported health symptoms since returning from the war that suggest dysfunction of the central nervous system (CNS). These symptoms include memory and concentration difficulties, fatigue, and headaches. Leading hypotheses for the etiology of these cognitive complaints include psychological factors and/or exposures to chemicals with neurotoxic properties. In this study, cognitive functioning was compared in treatment-seeking GW-deployed veterans and a treatment-seeking non–GW-deployed veteran control group. Results indicated that GW-deployed veterans performed significantly worse than the comparison group on tests of attention, visuospatial skills, visual memory, and mood. GW-deployed veterans who reported taking pyridostigmine bromide (PB) performed worse than GW-deployed veterans without PB use on executive system tasks. Treatment-seeking GW-deployed veterans with diagnoses of posttraumatic stress disorder (PTSD) did not differ on cognitive test measures compared with GW-deployed veterans without PTSD. No interaction effect of PTSD and PB use was found.     

How age affects memory task performance in clinically normal hearing persons

The main objective of this study is to investigate memory task performance in different age groups, irrespective of hearing status. Data are collected on a short-term memory task (WAIS-III Digit Span forward) and two working memory tasks (WAIS-III Digit Span backward and the Reading Span Test). The tasks are administered to young (20–30 years, n = 56), middle-aged (50–60 years, n = 47), and older participants (70–80 years, n = 16) with normal hearing thresholds. All participants have passed a cognitive screening task (Montreal Cognitive Assessment (MoCA)). Young participants perform significantly better than middle-aged participants, while middle-aged and older participants perform similarly on the three memory tasks. Our data show that older clinically normal hearing persons perform equally well on the memory tasks as middle-aged persons. However, even under optimal conditions of preserved sensory processing, changes in memory performance occur. Based on our data, these changes set in before middle age.