This study examined the ability of reaction time (RT) and Event-Related Potentials (ERP) to detect malingered neurocognitive deficit (MNCD)in two new tasks compared to the TOMM (N = 47). Honest (HON), malingering (MAL), and traumatic brain injury (TBI) groups were compared on accuracy, RT and ERP measures. Overall, the Test of Memory Malingering (TOMM) accuracy was the most effective at classifying groups (hit rate = 100%). Several non-TOMM accuracy variables and RT variables reached hit rates in the range of 71%-88%. The TOMM RT variable had an unlimited time for participants to respond and was the most successful RT variable compared to the Old/New and Repetition Priming tasks that had a short time limit for participants to respond (approximately 1.5 seconds). The classic old/new effect RT pattern was evident for both the HON and TBI groups with significantly faster RTs for old items compared to new items. A logistic regression was employed to see if a RT and/or ERP variable added any unique prediction power in detecting malingering. The frontal-posterior ERP difference score had unique prediction power to detect malingering when classifying MAL vs. TBI (hit rate = 86%). In the Old/New task, ERP responses of HON produced greater activity in the frontal region compared to the posterior region. The opposite trend was found in TBI (posterior activity andgt; frontal) and MAL showed no significant difference.

Doctor of Philosophy (Medicine) / Sleepiness is an important source of morbidity in the community, with potentially catastrophic consequences of occupational or driving injuries or accidents. Although many measures of sleepiness exist, there is no gold standard. The electroencephalograph (EEG) has been studied as an indicator of sleep pressure in the waking organism, or sleep depth. A mathematical model has been developed, relating the observed EEG to interactions between groups of neurons in the cortex and thalamus (Robinson, Rennie, Rowe, O'Connor, & Gordon, 2005; Robinson, Rennie, & Wright, 1997). These interactions are thought to be important in the transition from wake to sleep. Sleepiness is common in obstructive sleep apnea (OSA). The measurement of sleepiness would have great utility in quantifying the disease burden, measuring treatment response, or determining fitness for work or driving. This study will evaluate parameters derived from the EEG mathematical model as a measure of sleepiness. It is divided into the following four parts: 1. Subjects with likely OSA based on symptoms and demographics from an international database were compared with matched non-OSA controls. The OSA group showed deficits in executive function and abnormalities on evoked response potential testing. 2. Outcomes from a cross-sectional study in a sleep-clinic OSA population were aggregated by factor analysis into a five summary variables relevant to sleepiness: subjective sleepiness, mood & anxiety, memory & learning, driving, and executive functioning. 3. EEG mathematical model parameters from wake EEG recordings were related to the five summary outcomes. Executive function correlated with a parameter Z, representing the negative feedback loop between the thalamic reticular nucleus and the thalamocortical relay nuclei. 4. EEG model parameters during first NREM sleep cycle of 8 subjects with regular sleep architecture were studied. Net cortical excitation (parameter X) is predicted to increase across the cycle, while there was, as predicted, a greater inhibitory effect of the thalamic reticular nucleus upon thalamocortical relay cells (parameter Z). In this preliminary assessment, EEG model parameters reflecting thalamocortical interactions are sensitive to prefrontal lobe tasks such as executive function, which are known to be vulnerable to sleep loss and sleepiness, and these parameters also show variation with increasing sleep depth.

The identification of sport-related concussion (mild traumatic brain injury [mTBI]), its neurocognitive sequelae, and subsequent management have become a top priority within a spectrum of research disciplines at the intersection of psychology and sports medicine. To properly understand the complex neurocognitive changes associated with sport-related concussion in high school age individuals, multiple aspects of the injury were explored including the psychobiological nature of the injury, diagnostic concerns, normative adolescent neurocognitive development and abnormal changes as a result of the injury, and risk for further injury. While a wealth of literature exists in these areas, one aspect in particular, neurocognitive changes associated with sport-related mTBI in adolescents, is the focus of this research study. A review of the current research reveals a lack of exploration into neurocognitive deficits over-time as early as adolescence. To advance the understanding of how sport-related concussions may influence neurocognitive performance during this vulnerable age for brain development, multiple group comparisons were conducted to determine differences based upon reported concussion history. Results suggest that adolescents who experience sport-related concussion demonstrate significantly reduced levels of neurocognitive performance in several domains on initial baseline testing. Furthermore, these findings generally persist upon follow-up neurocognitive testing during adolescence. Thus, persistent neurocognitive deficits found during adolescence may have profound implications for brain development and concussion management.

Over the past 100 years, there has been significant progress in limiting the development of iodine deficiency disorders globally. The recognition that congenital cretinism can be eradicated through early iodine supplementation along with the implementation of salt iodination in many countries has substantially decreased the prevalence of severe iodine deficiency. Yet, there are still populations that are mildly iodine deficient, likely due to lack of mandated iodine supplementation programs. While some countries are qualified as iodine sufficient based upon the general population’s median urinary iodine concentration, the sub-population of pregnant women may be mildly to moderately iodine deficient. Thyroid hormone demand increases during gestation to support fetal thyroid function and neurodevelopment. Pregnant women require increased iodine intake during pregnancy to account for this increased demand and to make up for increased renal iodide losses. The American and European Thyroid Associations both recommend that pregnant women in mild to moderately deficient populations take a daily 150mcg iodine supplement while planning a pregnancy, pregnant, and lactating. Studies into the impact of mild to moderate iodine deficiency in pregnancy on long-term neurocognitive outcomes of offspring have shown varied results. Some have found that iodine sufficiency or supplementation in pregnancy is associated with higher intelligence quotient scores in offspring. Others have found no significant effect of iodine sufficiency and iodine supplementation on developmental outcomes. This proposal is a double-blind, placebo-controlled, randomized study evaluating the effect of iodine supplementation in pregnancy on long-term neurocognitive outcomes of offspring. The study will be implemented in the mildly iodine deficient population of Southern England. Results from this study will contribute to and likely expand upon the current body of literature. They will also bolster current recommendations for iodine supplementation in pregnancy. In addition, this study may have important public health consequences including discussions around mandatory salt iodization in mild to moderately deficient populations.

Objective: To extend previous research designs and examine cognitive performance up to 30 days postconcussion. Method: A prospective cohort design was used to examine 2000 athletes from 8 mid-Michigan area high schools to compare baseline neurocognitive performance with postconcussion neurocognitive performance. All concussed athletes were readministered the Immediate Post Assessment and Cognitive Test (ImPACT) at 2, 7, 14, 21, and 30 days postconcussion. Results: A total of 72 high school athletes (aged 15.8 ± 1.34 years) sustained a concussion. A significant within-subjects effect for reaction time (F = 10.01; P= 0.000), verbal memory (F = 3.05; P = 0.012), motor processing speed (F= 18.51; P = 0.000), and total symptoms following an injury (F= 16.45; P= 0.000) was found. Concussed athletes demonstrated a significant decrease in reaction time up to 14 days postconcussion (P = 0.001) compared with baseline reaction time. Reaction time returned to baseline levels at 21 days postinjury (P = 0.25). At 7 days postinjury, impairments in verbal memory (P= 0.003) and motor processing speed (P= 0.000) were documented and returned to baseline levels by 14 days postinjury. Concussed athletes self-reported significantly more symptoms at 2 days postconcussion (P = 0.000) and exhibited a resolution of symptoms by 7 days postinjury (P = 0.06). Conclusion: High school athletes could take up to 21 days to return to baseline levels for reaction time. These data support current recommendations for the conservative management of concussion in the high school athlete.

Patients with schizophrenia frequently display neurocognitive dysfunction, and genetic studies suggest it to be an endophenotype for schizophrenia. Genetic studies of such traits may thus help elucidate the biological pathways underlying genetic susceptibility to schizophrenia. This study aimed to identify loci influencing neurocognitive performance in schizophrenia. The sample comprised of 1207 affected individuals and 1035 unaffected individuals of Han Chinese ethnicity from 557 sib-pair families co-affected with DSM-IV (Diagnostic and Statistical Manual, Fourth Edition) schizophrenia. Subjects completed a face-to-face semi-structured interview, the continuous performance test (CPT) and the Wisconsin card sorting test (WCST), and were genotyped with 386 microsatellite markers across the genome. A series of autosomal genome-wide multipoint nonparametric quantitative trait loci (QTL) linkage analysis were performed in affected individuals only. Determination of genome-wide empirical significance was performed using 1000 simulated genome scans. One linkage peak attaining genome-wide significance was identified: 12q24.32 for undegraded CPT hit rate [nonparametric linkage z (NPL-Z) scores = 3.32, genome-wide empirical P = 0.03]. This result was higher than the peak linkage signal obtained in the previous genome-wide scan using a dichotomous diagnosis of schizophrenia. The identification of 12q24.32 as a QTL has not been consistently implicated in previous linkage studies on schizophrenia, which suggests that the analysis of endophenotypes provides additional information from what is seen in analyses that rely on diagnoses. This region with linkage to a particular neurocognitive feature may inform functional hypotheses for further genetic studies for schizophrenia.

Background: Efavirenz is associated with transient neuropsychiatric manifestations but the impact on neurocognition is unknown. Genetically determined black South Africans who are slow metabolizers of efavirenz may be at risk of toxicity. This study describes neuropsychiatric and neurocognitive manifestations of South African children with suspected efavirenz neurotoxicity. Method: This retrospective study describes clinical features of 12 children with suspected efavirenz neurotoxicity (2008 – 2014). Results: Twelve children were referred (aged 3 years 4 months to 12 years, mean 7 years 8 months; 8 indigenous African (black) and 4 mixed ancestry). Six had acute neuropsychiatric manifestations after 2-8 weeks (mean 5 weeks) on efavirenz including drowsiness, seizures, sleep disturbances, behavioural changes, ataxia and slurred speech. Symptoms resolved over a few weeks in four. Two black children were phenotypically slow metabolizers with high plasma efavirenz concentrations above normal range resulting in discontinuation of efavirenz. Nine children had neurocognitive concerns potentially exacerbated by long-term efavirenz (6-72 months therapy; mean 31 months), and showed poor performance in all neurocognitive domains. Conclusion: Efavirenz causes transient neuropsychiatric adverse effects and may contribute to poor longterm neurocognitive outcomes in HIV-infected children. Genetically slow metabolizers are at risk of neurotoxicity. Prospective studies comparing efavirenz-treated and efavirenz-naïve children are needed.

No description available.

Orofacial clefts are a group of congenital craniofacial deformities characterized by structural defects within and around the oral cavity. While some orofacial clefts are associated with an identifiable genetic or teratogenic syndrome, most are isolated or nonsyndromic. It has been well-documented that children born with nonsyndromic cleft lip and/or palate (NCL/P) are at-risk for poorer academic outcomes, especially within reading. Research into the cognitive functioning of patients with NCL/P has demonstrated that auditory-verbal memory and rapid naming are significant neuropsychological predictors of their lower reading achievement. Despite a solid compendium of research into the reading outcomes of those affected by NCL/P, very little research into the mathematical skills of this population exists. The current study examined whether the arithmetical computation skills of children, adolescents, and young adults with NCL/P differ significantly from healthy control participants. Comparisons of potential neuropsychological predictors of arithmetical computation were also conducted to determine whether these variables differ significantly for participants with NCL/P. Given the influence of language on both reading and mathematics and clear evidence of language impairments in individuals with NCL/P, it was hypothesized that arithmetical computation would be significantly lower for the NCL/P group. It was also hypothesized that the neuropsychological variables associated with lowered reading in NCL/P would be the strongest predictors of arithmetical computation. Results confirmed that arithmetical computation was significantly lower for the NCL/P group. Sustained attention, visual-spatial organization, auditory-verbal memory and rapid naming were significant predictors for the NCL/P group; rapid naming was the lone variable that was significantly more predictive of arithmetical computation for the NCL/P group than for control participants. These results suggest that inefficient verbal label retrieval related to short-term memory deficits underlie the computational difficulties of individuals with NCL/P. These findings have implications for approaches to remediation, as well as future research.

Introduction. Executive function refers to the top-down neurocognitive processes involved in flexible, goal-oriented behavior. A number of studies have shown positive effects of EF training. The overall aim of these studies was to explore the neurocognitive processes that support the development of EF by understanding how EF training works and what the active ingredients are. Particular interest was in isolating the role of reflection in EF training to understand its top-down affect on ACC-mediated conflict detection. Method. In Exp. 1 the neural markers of EF were explored by comparing ERPs of preschoolers who passed the DCCS and preschoolers who failed. Exp. 2 represents an attempt to replicate the key findings of Kloo & Perner, (2003, Exp. 2) that reflection training improves preschoolers’ performance on the DCCS and demonstrates far transfer. A shortened version of the training protocol was also tested (Exp. 3). In Exp. 4, the neural correlates of reflection training in preschoolers were explored by examining changes in the neural marker of EF found in Exp. 1. Results. In Exp. 1, the N2 amplitude was smaller (less negative) for children who passed the DCCS and were able to efficiently resolve the conflict in the stimuli than for children who failed and were unable to resolve the conflict. Exp. 2 replicated the findings of Kloo & Perner, (2003, Exp. 2) even using a brief (15 min) intervention targeting reflection (Exp. 3). In Exp. 4, one brief session of reflection training made children who initially failed the DCCS look like children who initially passed at both the behavioral and neural level (reduced N2 amplitude). Conclusion. Results suggest that reflective processing facilitates the development of EF in young children by teaching them to notice conflict, reflect on it, and formulate rules for resolving it, resulting in the down-regulation of ACC-mediated conflict detection.