Huntington disease (HD) is associated with decline in cognition and progressive morphological changes in brain structures. Cognitive reserve may represent a mechanism by which disease-related decline may be delayed or slowed. The current study examined the relationship between cognitive reserve and longitudinal change in cognitive functioning and brain volumes among prodromal (gene expansion-positive) HD individuals. Participants were genetically confirmed individuals with prodromal HD enrolled in the PREDICT-HD study. Cognitive reserve was computed as the composite of performance on a lexical task estimating premorbid intellectual level, occupational status, and years of education. Linear mixed effects regression (LMER) was used to examine longitudinal changes on four cognitive measures and three brain volumes over approximately 6 years. Higher cognitive reserve was significantly associated with a slower rate of change on one cognitive measure (Trail Making Test, Part B) and slower rate of volume loss in two brain structures (caudate, putamen) for those estimated to be closest to motor disease onset. This relationship was not observed among those estimated to be further from motor disease onset. Our findings demonstrate a relationship between cognitive reserve and both a measure of executive functioning and integrity of certain brain structures in prodromal HD individuals. (JINS, 2013, 19, 1–12).

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)

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)

This study examined cognitive test performance of second- and third-generation Japanese American (JA) adults, a relatively homogeneous Asian American subgroup. Sixty-five JA and 65 non-Hispanic White (NHW) adults, ages between 45 and 91, were administered the Boston Naming Test-2 (BNT), Letter Fluency Test, Semantic Fluency Test, California Verbal Learning Test (CVLT), Brief Visuospatial Memory Test-Revised (BVMT-R), and Trail Making Test. Levels of acculturation, quality of educational attainment, and generation status in the United States, were also collected. There were no significant differences in the scores between the two groups on the tests administered. JA and NHW groups, however, differed in the patterns of the associations between some of the test performance and demographic variables. JA adults showed a stronger age-score relationship on BNT, CVLT, and the BVMT-R. Furthermore, second-generation JA adults performed lower than the third-generation adults even after controlling for basic demographic variables on CVLT and Trail Making Test. Acculturation on the other hand did not explain score differences once demographic variables were considered. Our results suggest the importance of considering unique history and characteristics of ethnic groups, and interactions of the aging process and culture on tasks with different cognitive demands. (JINS, 2013, 19, 1–9)

Processing speed is the most impaired neuropsychological domain in schizophrenia and a robust predictor of functional outcome. Determining the specific cognitive operations underlying processing speed dysfunction and identifying their neural correlates may assist in developing pro-cognitive interventions. Response selection, the process of mapping stimuli onto motor responses, correlates with neuropsychological tests of processing speed and may contribute to processing speed impairment in schizophrenia. This study investigated the relationship between behavioral and neural measures of response selection, and a neuropsychological index of processing speed in schizophrenia. Twenty-six patients with schizophrenia and 21 healthy subjects underwent functional magnetic resonance imaging scanning during performance of two- and four-choice reaction time (RT) tasks and completed the Wechsler Adult Intelligence Scale-III (WAIS) Processing Speed Index (PSI). Response selection, defined as RT slowing between two- and four-choice RT, was impaired in schizophrenia and correlated with psychometric processing speed. Greater activation of the dorsolateral prefrontal cortex (PFC) was observed in schizophrenia and correlated with poorer WAIS PSI scores. Deficient response selection and abnormal recruitment of the dorsolateral PFC during response selection contribute to processing speed impairment in schizophrenia. Interventions that improve response selection and normalize dorsolateral PFC function may improve processing speed in schizophrenia. (JINS, 2013, 19, 1–10)

Individuals with post-traumatic stress disorder (PTSD) show a cognitive bias for threatening information, reflecting dysregulated executive control for affective stimuli. This study examined whether comorbid mild Traumatic Brain Injury (mTBI) with PTSD exacerbates this bias. A computer-administered Affective Go/No-Go task measured reaction times (RTs) and errors of omission and commission to words with a non–combat-related positive or negative valence in 72 deployed United States service members from the wars in Iraq and Afghanistan. Incidents of military-related mTBI were measured with the Boston Assessment of Traumatic Brain Injury-Lifetime. PTSD symptoms were measured with the Clinician-Administered PTSD Scale. Participants were divided into those with (mTBI+, n = 34) and without a history of military-related mTBI (mTBI−, n = 38). Valence of the target stimuli differentially impacted errors of commission and decision bias (criterion) in the mTBI+ and mTBI− groups. Specifically, within the mTBI+ group, increasing severity of PTSD symptoms was associated with an increasingly liberal response pattern (defined as more commission errors to negative distractors and greater hit rate for positive stimuli) in the positive compared to the negative blocks. This association was not observed in the mTBI− group. This study underscores the importance of considering the impact of a military-related mTBI and PTSD severity upon affective executive control. (JINS, 2013, 19, 1–10)

Closing-in (CI) refers to copying drawings near to or superimposed on the original model, and is often observed in Alzheimer's disease (AD) patients. Contrasting hypotheses have been suggested to explain CI, but no prospective study has directly verified these interpretations. We evaluated the role of frontal/executive versus visuo-spatial impairments in a prospective sample of AD patients, and also explored whether different types of CI are related to specific neuropsychological tasks. We enrolled 64 AD patients who underwent copying tasks and an extensive neuropsychological assessment of visuo-spatial and visuo-constructional skills, frontal/executive abilities and anterograde memory. AD patients with CI showed more severe impairment on frontal/executive functions than AD patients without CI. Moreover, the tendency to produce copies superimposed on the model was selectively associated with poor inhibitory control for irrelevant responses. On this basis, we suggest that different CI phenomena could be ascribed to distinctive frontal/executive defects. (JINS, 2013, 19, 1–7)

A family history of dementia is associated with an increased risk of developing Alzheimer's disease (AD) late in life (LOAD). This study marked the first attempt to assess the familial contribution to differences in cognitive performance in a large family-based group in the Chinese community. We enrolled 168 participants without dementia from a single pedigree with 9 probable AD patients diagnosed after age 65. These participants were evaluated with a comprehensive neuropsychological battery, the Chinese version of the Mini Mental State Examination, and the Alzheimer Disease Assessment Scale–Cognitive Subscale. Analyses found that extended family members of the LOAD pedigree showed similar performance on measures of global cognitive function and semantic memory compared to controls, but lower scores on episodic memory, attention, and executive function measures. These results indicate that the genetic influences on certain sub-cognitive domains are more detectable despite normal global cognitive function, and that family members with the LOAD pedigree are at risk for developing LOAD by virtue of their family history with an additive risk due to increased age. The findings in this study support the importance of documenting if there is a positive family history of AD in clinical evaluations. (JINS, 2013, 19, 1–11)

Although it is widely known that high intra-individual variability (IIV) is a key characteristic of attention deficit/hyperactivity disorder (ADHD), a detailed exploration of the IIV pattern during the time course of a cognitive task has never been carried out. In this study, 30 children with ADHD and 30 controls, were administered the Conners’ Continuous Performance Task (CPT-II). The across-block individual performance of the groups was analyzed using an ex-Gaussian approach, which enabled a clearer understanding of how individual response times (RTs) fluctuate during a task in comparison with conventional measures of central tendency. While the conventional measures showed a significant group effect on mean RTs but similar RT trends across blocks between the two groups, the ex-Gaussian results revealed no actual differences between the two groups in the normally distributed component of mean RTs (mu). In contrast to the control group, the children with ADHD showed a steep increase in the exponentially distributed component of RTs (tau) across blocks, thereby indicating that extremely long RTs progressively increased soon after the beginning of the task. Taken together, the results demonstrated that sustained attention deficit in ADHD can be detected by analyzing the IIV in the first few task blocks. (JINS, 2013, 19, 1–9)

The objective of this study is to systematically investigate sleep following moderate–severe pediatric traumatic brain injury (TBI). School-aged children with moderate–severe TBI identified via hospital records were invited to participate, along with a school-age sibling. Subjective reports and objective actigraphy correlates of sleep were recorded: Children's Sleep Habits Questionnaire (CSHQ), Sleep Self-Report questionnaire (SSR), and 5-night actigraphy. TBI participants (n = 15) and their siblings (n = 15) participated. Significantly more sleep problems were parent-reported (CSHQ: p = 0.003; d = 1.57), self-reported (SSR: p = 0.003; d = 1.40), and actigraph-recorded in the TBI group (sleep efficiency: p = 0.003; d = 1.23; sleep latency: p = 0.018; d = 0.94). There was no evidence of circadian rhythm disorders, and daytime napping was not prevalent. Moderate–severe pediatric TBI was associated with sleep inefficiency in the form of sleep onset and maintenance problems. This preliminary study indicates that clinicians should be aware of sleep difficulties following pediatric TBI, and their potential associations with cognitive and behavioral problems in a group already at educational and psychosocial risk. (JINS, 2013, 19, 1–6)

Research has shown that attention can be abnormally drawn to salient threat- or trauma-related information in individuals with posttraumatic stress and related psychological symptoms. The nature of this attentional bias is thought to derive from capture of attention toward potential threat overpowering the volitional, goal-directed attentional system. However, it is unclear whether this pattern of attentional dysregulation generalizes to salient, but non-emotional types of information. Using a well-established and sensitive measure of attentional capture, the current study demonstrates that posttraumatic psychological symptom severity is associated with the capture of attention by visually salient, non-emotional distractors. Specifically, during visual search for a unique shape, the presence of a task-irrelevant but salient color singleton disrupted search efficiency, and this disruption was correlated with both posttraumatic stress disorder (PTSD) and depression symptom severity as assessed by self-report. These findings suggest that posttraumatic stress and depression may be characterized as involving a general alteration of the balance between salience-based and goal-directed attentional systems. (JINS, 2013, 19, 1–6)

Cognitive reserve (CR) has been proposed as a latent variable that can account for the frequent discrepancy between an individual's underlying level of brain pathology and their observed clinical outcome. A possible behavioral manifestation of CR is best strategy choice. Older adults have been shown to choose sub-optimal strategies for performing various tasks. The present study attempted to investigate whether greater levels of CR could predict greater strategy selection, particularly in older adults. A computational estimation task was administered to 20 healthy young adults (mean age = 24.7 ± 3.6; 20–31 years) and 18 healthy older adults (68.2 ± 4.5; 62–77 years) wherein participants needed to estimate the product of two two-digit numbers by using one of two strategies. The results revealed an effect of age group on strategy choice and supported the hypothesis that CR is associated with increased strategy selection abilities. (JINS, 2013, 19, 1–4)