Individuals with mild traumatic brain injury (TBI) often have deficits in processing speed and working memory (WM) and there is a growing literature using functional imaging studies to document these deficits. However, divergent results from these studies revealed both hypoactivation and hyperactivation of neural resources after injury. We hypothesized that at least part of this variance can be explained by distinct demands between WM tasks. Notably, in this literature some WM tasks use discrete periods of encoding, maintenance, and retrieval, whereas others place continuous demands on WM. The purpose of this meta-analysis is to examine the differences in neural recruitment after mTBI to determine if divergent findings can be explained as a function of task demand and cognitive load. A comprehensive literature review revealed 14 studies using functional magnetic resonance imaging to examine brain activity of individuals with mTBI during working memory tasks. Three of the fourteen studies included reported hypoactivity, five reported hyperactivity, and the remaining six reported both hypoactivity and hyperactivity. Studies were grouped according to task type and submitted to GingerALE maximum likelihood meta-analyses to determine the most consistent brain activation patterns. The primary findings from this meta-analysis suggest that the discrepancy in activation patterns is at least partially attributable to the classification of WM task, with hyperactivation being observed in continuous tasks and hypoactivation being observed during discrete tasks. We anticipate that differential task load expressed in continuous and discrete WM tasks contributes to these differences. Implications for the interpretation of fMRI signals in clinical samples are discussed. (JINS, 2013, 19, 1–12)

We compared neuropsychological profiles in children with shunted hydrocephalus secondary to aqueductal stenosis (AS), a rare form of congenital hydrocephalus, and spina bifida myelomeningocele (SBM), a common form of congenital hydrocephalus. Participants were 180 children with shunted hydrocephalus grouped according to etiology: SBM (n = 151), AS (n = 29), and typically developing (TD; n = 60) individuals. The group with AS performed below the TD group on all tasks except for reading, and their overall performance was higher than the group with SBM, who had the lowest performance in the sample. Both clinical groups significantly differed from the TD group on tasks of spatial function, concept formation, motor function, and memory. Performance of the subgroup of AS children with normal cerebellum status approximated that of the TD group, while those with cerebellar anomalies performed lower than others with AS. Cerebellar abnormalities (present in the whole SBM group and in a subset of the AD group) are associated with more compromise of cognitive as well as motor function. (JINS, 2012, 18, 1–10)

Given the importance of identifying dementia prodromes for future treatment efforts, we examined two methods of diagnosing mild cognitive impairment (MCI) and determined whether empirically-derived MCI subtypes of these diagnostic methods were consistent with one another as well as with conventional MCI subtypes (i.e., amnestic, non-amnestic, single-domain, multi-domain). Participants were diagnosed with MCI using either conventional Petersen/Winblad criteria (n = 134; >1.5 SDs below normal on one test within a cognitive domain) or comprehensive neuropsychological criteria developed by Jak et al. (2009) (n = 80; >1 SD below normal on two tests within a domain), and the resulting samples were examined via hierarchical cluster and discriminant function analyses. Results showed that neuropsychological profiles varied depending on the criteria used to define MCI. Both criteria revealed an Amnestic subtype, consistent with prodromal Alzheimer's disease (AD), and a Mixed subtype that may capture individuals in advanced stages of MCI. The comprehensive criteria uniquely yielded Dysexecutive and Visuospatial subtypes, whereas the conventional criteria produced a subtype that performed within normal limits, suggesting its susceptibility to false positive diagnostic errors. Whether these empirically-derived MCI subtypes correspond to dissociable neuropathologic substrates and represent reliable prodromes of dementia will require additional follow-up. (JINS, 2013, 19, 1–11)

The theory of cognitive reserve attempts to explain why some individuals are more resilient to age-related brain pathology. Efforts to explore reserve have been hindered by measurement difficulties. Reed et al. (2010) proposed quantifying reserve as residual variance in episodic memory performance that remains after accounting for demographic factors and brain pathology (whole brain, hippocampal, and white matter hyperintensity volumes). This residual variance represents the discrepancy between an individual's predicted and actual memory performance. The goals of the present study were to extend these methods to a larger, community-based sample and to investigate whether the residual reserve variable is explained by age, predicts longitudinal changes in language, and predicts dementia conversion independent of age. Results support this operational measure of reserve. The residual reserve variable was associated with higher reading ability, lower likelihood of meeting criteria for mild cognitive impairment, lower odds of dementia conversion independent of age, and less decline in language abilities over 3 years. Finally, the residual reserve variable moderated the negative impact of memory variance explained by brain pathology on language decline. This method has the potential to facilitate research on the mechanisms of cognitive reserve and the efficacy of interventions designed to impart reserve. (JINS, 2013, 19, 1–9)

For this pilot study, we compared performance of 15 adolescents with moderate–severe traumatic brain injury (TBI) to that of 13 typically developing (TD) adolescents in predicting social actions and consequences for avatars in a virtual microworld environment faced with dilemmas involving legal or moral infractions. Performance was analyzed in relation to cortical thickness in brain regions implicated in social cognition. Groups did not differ in number of actions predicted nor in reasons cited for predictions when presented only the conflict situation. After viewing the entire scenario, including the choice made by the avatar, TD and TBI adolescents provided similar numbers of short-term consequences. However, TD adolescents provided significantly more long-term consequences (p = .010). Additionally, for the Overall qualitative score, TD adolescents’ responses were more likely to reflect the long-term impact of the decision made (p = .053). Groups differed in relation of the Overall measure to thickness of right medial prefrontal cortex/frontal pole and precuneus, with stronger relations for the TD group (p < .01). For long-term consequences, the relations to the posterior cingulate, superior medial frontal, and precentral regions, and to a lesser extent, the middle temporal region, were stronger for the TBI group (p < .01). (JINS, 2013, 19, 1–10.)

In this study, we addressed the relation between specific deficits in cognitive control and schizotypal symptomatology in adolescents with autism spectrum disorders (ASD) diagnosed in childhood. We aimed to identify cognitive control deficits as markers of vulnerability to the development of schizophrenia spectrum pathology in ASD. Symptoms of autism and the risk for schizotypal symptomatology were assessed in 29 high-functioning adolescents with ASD, and compared with 40 typically developing adolescents. Cognitive control (response inhibition, mental flexibility, visuo-motor control, interference control, and perseveration) was evaluated for specific association with schizotypal symptomatology. Impaired response inhibition appeared to be strongly and specifically associated with schizotypal symptomatology in adolescents with ASD, especially those with positive and disorganized symptoms. Response inhibition problems could indicate vulnerability to the development of schizotypal symptomatology in ASD. (JINS, 2013, 19, 1–10)

Children with spina bifida myelomeningocele (SBM) are more likely to display a pattern of good-decoding/poor comprehension than their neurologically intact peers. The goals of the current study were to (1) examine the cognitive origins of one of the component skills of comprehension, bridging inferences, from a developmental perspective and (2) to test the effects of those relations on reading comprehension achievement. Data from a sample of children with SBM and a control group (n = 78) who participated in a longitudinal study were taken from age 36-month and 9.5-year time points. A multiple mediation model provided evidence that three preschool cognitive abilities (working memory/inhibitory control, oral comprehension, narrative recall), could partially explain the relation between group and bridging inference skill. A second mediation model supported that each of the 36-month abilities had an indirect effect on reading comprehension through bridging inference skill. Findings contribute to an understanding of both typical and atypical comprehension development, blending theories from the developmental, cognitive, and neuropsychological literature. (JINS, 2013, 19, 1–10)

To study the natural recovery from sports concussion, 12 concussed high school football athletes and 12 matched uninjured teammates were evaluated with symptom rating scales, tests of postural balance and cognition, and an event-related fMRI study during performance of a load-dependent working memory task at 13 h and 7 weeks following injury. Injured athletes showed the expected postconcussive symptoms and cognitive decline with decreased reaction time (RT) and increased RT variability on a working memory task during the acute period and an apparent full recovery 7 weeks later. Brain activation patterns showed decreased activation of right hemisphere attentional networks in injured athletes relative to controls during the acute period with a reversed pattern of activation (injured > controls) in the same networks at 7 weeks following injury. These changes coincided with a decrease in self-reported postconcussive symptoms and improved cognitive test performance in the injured athletes. Results from this exploratory study suggest that decreased activation of right hemisphere attentional networks mediate the cognitive changes and postconcussion symptoms observed during the acute period following concussion. Conversely, improvement in cognitive functioning and postconcussive symptoms during the subacute period may be mediated by compensatory increases in activation of this same attentional network. (JINS, 2013, 19, 1–10)

Individuals with fetal alcohol spectrum disorders (FASD) have difficulties with cognitive-based executive function (EF) tasks. The goal of the present study was to determine if children with FASD have impairments on the Iowa Gambling Task (IGT), which measures affective EF (i.e., decision-making and risk-taking). Individuals with FASD (n = 31) and healthy controls (n = 31), aged 8–17 completed the IGT. Children with FASD were significantly impaired on the IGT compared to controls. Over the course of the task, control scores improved, whereas children with FASD exhibited an overall decrease in scores. Scores increased significantly with age in the control group but did not differ significantly with age for FASD participants. Children with FASD exhibited decision-making and risk-taking impairments on a hot EF task. Children with FASD did not appear to learn from negative experiences and shift to making more positive decisions over time and their performance did not improve with age. The implications of poor task performance and a lack of age-related findings in children with FASD are discussed. (JINS, 2012, 18, 1–8)

The process of checking in an everyday task to ensure error prevention/error correction, has not been systematically documented in relation to everyday action errors. This is surprising, given that studies of everyday task performance in people with dementia suggest poor error monitoring (error detection/correction). The present study documented age-related changes in errors and error monitoring behaviors, including the novel variable of checking (verbal/non-verbal gestures indicating active task monitoring), in an everyday task. In a 2 × 2 mixed-subjects design (n = 57), young and older adults performed a tea-making task under standard and dual-task conditions. Error rates were similar across age-groups and conditions. The dual-task condition reduced verbal checking and increased microslips (initiation and termination of an error before the error is completed) for both age-groups, when compared to the standard condition. In the standard condition, older adults engaged in more verbal checks than young adults, but this was not associated with improved task accuracy. Thus, both age-groups do engage in checking during an everyday task, but this checking had little impact on task accuracy. Consequently, checking may not be a necessary part of performance accuracy. Future studies should investigate whether enhanced awareness would make monitoring more effective. (JINS, 2013, 19, 1–10)

The present functional magnetic resonance imaging (fMRI) study investigated developmental differences in functional connectivity associated with true and false memory retrieval. A sample of 8- to 9-year-olds and adults (N = 31) was assessed with the Deese/Roediger-McDermott (DRM) paradigm, known to induce high levels of false recognition of lures that are semantically associated with studied items. The strength of semantic association among list items was manipulated. Relative to children, adults correctly recognized more studied items and falsely recognized more critical lures. High-association lists resulted in higher recognition of both studied items and critical lures. Functional connectivity analysis revealed that, overall, true recognition was supported by coupling within two hippocampal-temporal and fronto-parietal set of regions; in contrast, coupling among more distributed hippocampal-temporal-parietal-frontal regions was observed during false recognition. Critically, adults, compared to children, exhibited stronger hippocampal/parietal coupling and stronger hippocampal/dorsolateral prefrontal cortex (PFC) coupling for veridical recognition of high-associative strength items. In contrast, children, compared to adults, exhibited stronger hippocampus/ventrolateral PFC coupling and stronger bilateral middle-temporal gyrus/ventrolateral PFC coupling for high-associative strength critical lures. Our results underscored a role for the anterior hippocampus in true and false recognition, showing different functional patterns as a function of age and association strength. (JINS, 2013, 19, 1–11)

This study compared mathematical outcomes in children with predominantly moderate to severe traumatic brain injury (TBI; n = 50) or orthopedic injury (OI; n=47) at 2 and 24 months post-injury. Working memory and its contribution to math outcomes at 24 months post-injury was also examined. Participants were administered an experimental cognitive addition task and standardized measures of calculation, math fluency, and applied problems; as well as experimental measures of verbal and visual-spatial working memory. Although children with TBI did not have deficits in foundational math fact retrieval, they performed more poorly than OIs on standardized measures of math. In the TBI group, performance on standardized measures was predicted by age at injury, socioeconomic status, and the duration of impaired consciousness. Children with TBI showed impairments on verbal, but not visual working memory relative to children with OI. Verbal working memory mediated group differences on math calculations and applied problems at 24 months post-injury. Children with TBI have difficulties in mathematics, but do not have deficits in math fact retrieval, a signature deficit of math disabilities. Results are discussed with reference to models of mathematical cognition and disability and the role of working memory in math learning and performance for children with TBI. (JINS, 2013, 19, 1–10)

Sport-related concussion (SRC) is typically followed by clinical recovery within days, but reports of prolonged symptoms are common. We investigated the incidence of prolonged recovery in a large cohort (n = 18,531) of athlete seasons over a 10-year period. A total of 570 athletes with concussion (3.1%) and 166 controls who underwent pre-injury baseline assessments of symptoms, neurocognitive functioning and balance were re-assessed immediately, 3 hr, and 1, 2, 3, 5, 7, and 45 or 90 days after concussion. Concussed athletes were stratified into typical (within 7 days) or prolonged (> 7 days) recovery groups based on symptom recovery time. Ten percent of athletes (n = 57) had a prolonged symptom recovery, which was also associated with lengthier recovery on neurocognitive testing (p < .001). At 45–90 days post-injury, the prolonged recovery group reported elevated symptoms, without deficits on cognitive or balance testing. Prolonged recovery was associated with unconsciousness [odds ratio (OR), 4.15; 95% confidence interval (CI) 2.12–8.15], posttraumatic amnesia (OR, 1.81; 95% CI, 1.00–3.28), and more severe acute symptoms (p < .0001). These results suggest that a small percentage of athletes may experience symptoms and functional impairments beyond the typical window of recovery after SRC, and that prolonged recovery is associated with acute indicators of more severe injury. (JINS, 2012, 18, 1–12)

Intraindividual variability (IIV) refers to reaction time (RT) variation across the trials of a given cognitive task. Little research has contrasted different measures of IIV or assessed how many RT trials are required to provide a robust measure of the construct. We, therefore, investigated three measures of IIV (raw SD, coefficient of variation, and intraindividual SD statistically removing time-on-task effects) in relation to frontal white matter hyperintensities (obtained through structural MRI) in 415 cognitively normal community-dwelling adults aged 44 to 48 years. Results indicated the three IIV measures did not differ greatly in predictions of white matter hyperintensities, although it is possible that time-on-task effects were influential. As few as 20 trials taking approximately 52 s to administer provided a reliable prediction of frontal white matter hyperintensities. We conclude that future work should evaluate the comparative utility of different IIV measures in relation to persons exhibiting clear neuropathology. (JINS, 2013, 19, 1–6)

It has been hypothesized that exposure to repetitive head trauma from contact sports over a long-playing career may eventuate in an increased risk of late-life cognitive impairment. There are currently two competing hypotheses about the possible mechanism underlying such impairment. One is the presence of a unique neurodegenerative disorder known as “chronic traumatic encephalopathy” (CTE). The other is diminished cerebral reserve leading to the earlier clinical expression of age-related neurodegenerative diseases such as mild cognitive impairment (MCI) and Alzheimer's disease (AD). The present study examined informant AD8 inventory data in a sample of 513 retired National Football League (NFL) players. These data were indicative of possible cognitive impairment in 35.1% of this relatively young sample. A comparison of neurocognitive profiles in a subsample of this group to a clinical sample of patients with a diagnosis of MCI due to AD revealed a highly similar profile of impairments. Overall, the data suggest that there may be an increased prevalence of late-life cognitive impairment in retired NFL players, which may reflect diminished cerebral reserve. The findings are considered preliminary, but emphasize the need for larger, controlled studies on this issue. (JINS, 2013, 19, 1–8)

Several factors have been linked to severity of postconcussive-type (neurobehavioral) symptoms. In this study, predictors of neurobehavioral symptoms were examined using multivariate methods to determine the relative importance of each. Data regarding demographics, symptoms, current alcohol use, history of traumatic brain injury (TBI), orthopedic injuries, and psychiatric/developmental diagnoses were collected via questionnaire from 3027 university students. The most prominent predictors of symptoms were gender, history of depression or anxiety, history of attention-deficit/hyperactivity disorder or learning disability diagnosis, and frequency of alcohol use. Prior mild TBI was significantly related to overall symptoms, but this effect was small in comparison to other predictors. These results provide further evidence that neurobehavioral symptoms are multi-determined phenomena, and highlight the importance of psychiatric comorbidity, demographic factors, and health behaviors to neurobehavioral symptom presentation after mild TBI. (JINS, 2013, 19, 1–9)

Although more severe brain injuries have long been associated with persisting neurocognitive deficits, an increasing body of literature has shown that children/adolescents with single, uncomplicated mild traumatic brain injury (mTBI) do not exhibit long-lasting neurocognitive impairments. Nonetheless, clinical experience and our previous report (Babikian, 2011) showed that a minority of children/adolescents exhibit persistent cognitive problems using performance based measures following what appear to be relatively mild injuries. Predictors of poor neurocognitive outcomes were evaluated in 76 mTBI and 79 Other Injury subjects to determine the relative contributions of indices of injury severity, clinical symptomatology, demographic factors, and premorbid functioning in predicting 1-month and 12-month neurocognitive impairment on computerized or paper and pencil measures. Injury severity indicators or type of injury (head vs. other body part) did not predict either 1-month or 12-month cognitive impairment status. Rather, premorbid variables that antedated the injury (parental education, premorbid behavior and/or learning problems, and school achievement) predicted cognitive impairments. When post-injury neurocognitive impairments are observed in survivors of mild injuries (head or other body part), a sound understanding of their etiology is critical in designing appropriate intervention plans. Clinical and research implications are discussed. (JINS, 2012, 18, 1–10)

Although neurocognition is commonly described in terms of different functional domains, some factor analytic studies have suggested a simpler dimensional structure for neuropsychological (NP) tests in patients with schizophrenia. Standardized tasks of everyday functioning, or tests of “functional capacity” (FC), are viewed differently from traditional NP tests, and are hence used as a co-primary measure in treatment studies. However, FC and NP tests have been found to be highly correlated. In fact, a recent study of ours suggested that performances on these different types of tasks constituted a single latent trait in a cross-sectional analysis. The current study examined the longitudinal factor structure of a combined set of NP and FC tests. Patients with schizophrenia (n = 195) were examined at two assessment occasions separated by periods ranging from 6 weeks to 6 months. Participants were assessed with the MATRICS Consensus Cognitive Battery (MCCB) and two performance-based assessments of FC. A single latent trait was extracted using full information maximum likelihood procedures, and its temporal stability was examined in terms of: stability of the latent trait scores, the inter-correlations of the three indicators of the latent trait, and the stability of loadings for the FC and NP items underlying the latent trait at the two measurement occasions. All indices of temporal stability were confirmed, with stability not related to follow-up duration. Variation in clinical symptoms and treatments across the measurement occasions was negligible. These findings raise the question of whether cognitive abilities measured by NP tests and FC instruments are tapping a single ability construct, which might have shared causal influences as well. (JINS, 2013, 19, 1–8)