Evidence Of Executive Dysfunction Research Articles

Impaired cognition in narcolepsy: clinical and neurobiological perspectives.

In addition to well-known symptoms such as sleepiness and cataplexy, many people with narcolepsy have impaired cognition, reporting inattention, poor memory, and other concerns. Unfortunately, research on cognition in narcolepsy has been limited. Strong evidence demonstrates difficulties with sustained attention, but evidence for executive dysfunction and impaired memory is mixed. Animal research provides some insights into how loss of the orexin neurons in narcolepsy type 1 may give rise to impaired cognition via dysfunction of the prefrontal cortex, and cholinergic and monoaminergic systems. This paper reviews some of these clinical and preclinical findings, provides a neurobiological framework to understand these deficits, and highlights some of the many key unanswered questions.

Executive function and adult homelessness, true impairment or frontal lobology?

Homelessness is associated with multiple risk factors for neurocognitive impairment. Past research with people experiencing homelessness has described "frontal lobe" dysfunction including behavioral disorders and executive cognitive impairments. In the current study, 72 adults experiencing homelessness were assessed with a standardized assessment of executive function, and interviewed regarding neurological and psychiatric history. When compared to a control sample of 25 never-homeless participants, and controlling for level of education, there was little evidence for executive dysfunction in the sample of people experiencing homelessness. Levels of substance abuse, past head injury, and post-traumatic stress disorder were notably high. However, there were no statistically significant associations between cognitive task performance and clinical or substance abuse variables. Gambling was surprisingly infrequent, but risk-taking behavior among intravenous drug users was common. Though in neither case was it linked to executive function. Overall, there was little evidence for executive impairment in this sample of people experiencing homelessness. I suggest that past research has often used inappropriate criteria for "normal" performance, particularly comparing people experiencing homelessness to control data of relatively high education level. This has led to elements of "frontal lobology," that is, clinical neuroscience research that tends to overly link non-typical or pathological behavior to frontal lobe impairment. When appropriate comparisons are made, controlling for education level, as in this study, associations between executive function impairments and adult homelessness may be weaker than previously reported.

3551 Intermittent Theta Burst Stimulation to Relieve Depression and Executive Function impairment in older adults

OBJECTIVES/SPECIFIC AIMS: The objective of the study is to examine the ability of iTBS to improve depression and executive impairment in depressed older adults. If effective, this treatment will have the potential to improve the quality of life in LLD. METHODS/STUDY POPULATION: From 12- 2016 to date older adults (60 – 85 y/o) in a major depressive episode, with evidence of executive dysfunction (on the NIH Tool Box battery) were enrolled. iTBS protocol: This brief paradigm (3 min 9 seconds duration) was administered on weekdays for four weeks (20 sessions total). Stimulation intensity was set up to 120% of the observed motor threshold. Depression primary outcome: Change in the Montgomery Asberg Depression Rating Scale (MADRS) from baseline to the end of iTBS course. Executive function primary outcome: Change in executive measures from the electronic NIH Tool Box cognitive domain battery8. Executive secondary outcome: Change in scores from baseline to the end of iTBS on the Frontal Systems Behavior Scale (FrSBe), this self reported instrument measures dys-executive behavior. Statistical Analysis: paired t-test examined changes in depression and executive variables from baseline to post iTBS. Pearson correlation examined the association between degree of mood improvement and degree of improvement in executive function. SPSS v 24 was used for all analyses. RESULTS/ANTICIPATED RESULTS: We examined 11 subjects. Primary outcomes: Patients showed a significant decrease in scores on the Montgomery Asberg Depression Rating Scale (MADRS) from baseline Mean (M) = 27.73, Standard Deviation (SD) 8.2 to the end of 4 weeks of iTBS: M = 15.91, SD = 10.05, t = 7.4, p < .001. The Flanker Inhibitory Control and attention test significantly improved from baseline M = 91.0, SD = 7 to the end of iTBS M = 98.7, SD = 12.8, t = −2.9, p = .014 (higher scores at week 4 denote improvement). The List Sorting Working Memory test and the Dimensional Change Card sort a measure of cognitive flexibility improved but did not reach statistical significance. The self reported executive measure improved from baseline M = 48.6, SD = 9.4 to post iTBS M = 39.4, SD = 8.5, t = 3.8, p = .003 (lower scores at week 4 denote improvement). We also examined whether the degree of improvement in depression related to the degree of improvement in executive function. We found positive correlations between change in mood scores with iTBS with change in executive scores with iTBS, with a strong relationship with working memory r = 0.34. Tolerability and Side effects: Common side effects were twitching in facial muscles during the stimulation (n =11), headaches (n =10) and pain or discomfort at the stimulation site and face (n =4). One participant withdrew due to intolerance to the stimulation. DISCUSSION/SIGNIFICANCE OF IMPACT: The iTBS paradigm was effective in improving mood and executive function in older adults. Both the psychometric measure and the self reported executive function measure (indicative of dysexecutive behavior) reflected improvements post iTBS. Improvement in executive function was correlated with depression improvement. We targeted the Dorso Lateral Prefrontal cortex, which exhibits decreased connectivity with the dorsal anterior cingulate in depressed elderly and is a key in orchestration of executive function. Our findings are consistent with the conceptualization of depression as a circuit level disorder affecting interconnected networks involving mood and cognition. Although we demonstrated potential therapeutic effects, the mechanism of action of iTBS remains unknown. We are presently conducting a randomized controlled trial to examine the effects of iTBS on brain connectivity using functional MRI. Results of this study underway will hopefully demonstrate engagement of the TMS target and contribute to a neurocircuitry based approach treatment of geriatric depression.

The executive profile of children with Benign Epilepsy of Childhood with Centrotemporal Spikes and Temporal Lobe Epilepsy.

Benign Epilepsy of Childhood with Centrotemporal Spikes (BECTS) and temporal lobe epilepsy (TLE) represent two distinct models of focal epilepsy of childhood. In both, there is evidence of executive dysfunction. The purpose of the present study was to identify particular deficits in the executive function that would distinguish children with BECTS from children with TLE. We prospectively evaluated 19 consecutive children and adolescents with TLE with hippocampal sclerosis (HS) (57.9% male; mean 11.74years [SD 2.05]; mean IQ 95.21 [SD 15.09]), 19 with BECTS (36.8% male; mean 10.95years [SD 2.33]; mean IQ 107.40 [SD 16.01]), and 21 age and gender-matched controls (33.3% male; mean 11.86years [SD 2.25]; mean IQ 108.67 [15.05]). All participants underwent a neuropsychological assessment with a comprehensive battery for executive and attentional functions. We used ANOVA and chi-square to evaluate differences on demographic aspects among groups (BECTS, TLE-HS, and control groups). Group comparisons on continuous variables were complemented by MANOVA and Bonferroni posthoc comparisons. Patients with BECTS had worse performance than controls in: Matching Familiar Figures Test, time (p=0.001); Matching Familiar Figures Test, time×errors index (p<0.001); Verbal Fluency for foods (p=0.038); Trail Making Test, part B time (p=0.030); Trail Making Test, part B number of errors (p=0.030); and WCST, number of categories achieved (p=0.043). Patients with BECTS had worse performance than patients with TLE-HS on Matching Familiar Figures Test, time (p=0.004), and Matching Familiar Figures Test, time×errors index (p<0.001). Patients with TLE-HS had worse performance than controls on the following tests: Verbal Fluency for foods (p=0.004); Wisconsin Card Sorting Test, the number of categories achieved (p<0.001); and Wisconsin Card Sorting Test, the number of perseverative errors (p=0.028). Patients with TLE-HS had worse performance than patients with BECTS on Digit Backward (p=0.002); and the Wisconsin Card Sorting Test, the number of perseverative errors (p<0.001). Patients with TLE and BECTS present distinct cognitive profiles. Patients with TLE-HS had worse performance in mental flexibility, concept formation, and working memory compared to BECTS. Patients with BECTS had worse inhibitory control compared to children with TLE-HS. Both TLE-HS and BECTS had a higher number of errors on an inhibitory control test. However, patients with BECTS had a slower mental processing even when compared to patients with TLE-HS. Rehabilitation programs for children with epilepsy must include children with benign epilepsies and must take into account the epileptic syndrome and its particular neurocognitive phenotype.

Autism spectrum disorders: a meta-analysis of executive function

Evidence of executive dysfunction in autism spectrum disorders (ASD) across development remains mixed and establishing its role is critical for guiding diagnosis and intervention. The primary objectives of this meta-analysis is to analyse executive function (EF) performance in ASD, the fractionation across EF subdomains, the clinical utility of EF measures and the influence of multiple moderators (for example, age, gender, diagnosis, measure characteristics). The Embase, Medline and PsychINFO databases were searched to identify peer-reviewed studies published since the inclusion of Autism in DSM-III (1980) up to end of June 2016 that compared EF in ASD with neurotypical controls. A random-effects model was used and moderators were tested using subgroup analysis. The primary outcome measure was Hedges’ g effect size for EF and moderator factors. Clinical sensitivity was determined by the overlap percentage statistic (OL%). Results were reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A total of 235 studies comprising 14 081 participants were included (N, ASD=6816, Control=7265). A moderate overall effect size for reduced EF (Hedges’ g=0.48, 95% confidence interval (CI) 0.43–0.53) was found with similar effect sizes across each domain. The majority of moderator comparisons were not significant although the overall effect of executive dysfunction has gradually reduced since the introduction of ASD. Only a small number of EF measures achieved clinical sensitivity. This study confirms a broad executive dysfunction in ASD that is relatively stable across development. The fractionation of executive dysfunction into individual subdomains was not supported, nor was diagnostic sensitivity. Development of feasible EF measures focussing on clinical sensitivity for diagnosis and treatment studies should be a priority.

Pretreatment Differences in Intraindividual Variability in Reaction Time between Women Diagnosed with Breast Cancer and Healthy Controls.

Chemotherapy has adverse effects on cognitive performance in women treated for breast cancer, but less is known about the period before chemotherapy. Studies have focused on mean level of performance, yet there is increasing recognition that variability in performance within an individual is also an important behavioral indicator of cognitive functioning and underlying neural integrity. We examined intraindividual variability (IIV) before chemotherapy and surgery in women diagnosed with breast cancer (n=31), and a healthy control group matched on age and education (n=25). IIV was calculated across trials of a computerized Stroop task, including an examination of the slowest and fastest trials of reaction time (RT) responses. The groups were equivalent on overall accuracy and speed, and participants in both groups were less accurate and slower on incongruent trials compared with congruent trials. However, women with breast cancer became more variable with increased task difficulty relative to healthy controls. Among the slowest RT responses, women with breast cancer were significantly more variable than healthy controls on incongruent trials. This suggests that a specific variability-producing process (e.g., attentional lapses) occurs in task conditions that require executive control (e.g., incongruent trials). Results are consistent with other evidence of executive dysfunction among women treated for breast cancer. These findings highlight the importance of pretreatment assessment and show that variability in performance provides information about cognition that measures of central tendency do not.

P.2.013 Effects of MK-801 and medial prefrontal cortex lesions on cognitive flexibility in a novel task based on the change of interval schedules

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability in males and the most common genetic cause of autism. Although executive dysfunction is consistently found in humans with FXS, evidence of executive dysfunction in Fmr1 KO mice, a mouse model of FXS, has been inconsistent. One possible explanation for this is that executive dysfunction in Fmr1 KO mice, similar to humans with FXS, is only evident when cognitive demands are high. Using touchscreen operant conditioning chambers, male Fmr1 KO mice and their male wildtype littermates were tested on the acquisition of a pairwise visual discrimination followed by four serial reversals of the response rule. We assessed reversal learning performance under two different conditions. In the first, the correct stimulus was salient and the incorrect stimulus was non-salient. In the second and more challenging condition, the incorrect stimulus was salient and the correct stimulus was non-salient; this increased cognitive load by introducing conflict between sensory-driven (i.e., bottom-up) and task-dependent (i.e., top-down) signals. Fmr1 KOs displayed two distinct impairments relative to wildtype littermates. First, Fmr1 KOs committed significantly more learning-type errors during the second reversal stage, but only under high cognitive load. Second, during the first reversal stage, Fmr1 KOs committed significantly more attempts to collect a reward during the timeout following an incorrect response. These findings indicate that Fmr1 KO mice display executive dysfunction that, in some cases, is only evident under high cognitive load.

Delineation of the working memory profile in female FMR1 premutation carriers: The effect of cognitive load on ocular motor responses

Fragile X mental retardation 1 (FMR1) premutation carriers (PM-carriers) are characterised as having mid-sized expansions of between 55 and 200 CGG repeats in the 5′ untranslated region of the FMR1 gene. While there is evidence of executive dysfunction in PM-carriers, few studies have explicitly explored working memory capabilities in female PM-carriers. 14 female PM-carriers and 13 age- and IQ-matched healthy controls completed an ocular motor n-back working memory paradigm. This task examined working memory ability and the effect of measured increases in cognitive load. Female PM-carriers were found to have attenuated working memory capabilities. Increasing the cognitive load did not elicit the expected reciprocal increase in the task errors for female PM-carriers, as it did in controls. However female PM-carriers took longer to respond than controls, regardless of the cognitive load. Further, FMR1 mRNA levels were found to significantly predict PM-carrier response time. Although preliminary, these findings provide further evidence of executive dysfunction, specifically disruption to working memory processes, which were found to be associated with increases in FMR1 mRNA expression in female PM-carriers. With future validation, ocular motor paradigms such as the n-back paradigm will be critical to the development of behavioural biomarkers for identification of PM-carrier cognitive-affective phenotypes.

84. Functional evaluation of central cholinergic circuits in patients with Parkinson’s disease and freezing of gait

Abnormalities of cholinergic circuitries may be at the basis of cognitive dysfunction, gait disorders, and falls and they may also be important for freezing of gait (FOG). Aim of this study is the evaluation of central cholinergic circuits by means of short latency afferent inhibition (SAI) technique in patients with Parkinson’s disease (PD) and freezing of gait (FOG+). We applied the SAI technique in 14 FOG+ patients, in 10 patients without freezing (FOG−) and in 11 age-matched normal controls. All PD patients also underwent a comprehensive battery of neuropsychological tests. Mean SAI was not significantly different in FOG+ patients when compared with FOG− patients and controls. Neuropsychological examination showed mild cognitive impairment (MCI) in 10 out of the 14 FOG+ patients, and in 1 out of the 10 FOG−. Notably, the pattern of cognitive impairment included a variable degree of deficits in executive and visuospatial domains. Our SAI findings suggest the integrity of cholinergic circuits in PD patients with FOG. In addition, neuropsychological findings provide further evidence of executive dysfunction in the pathogenesis of FOG.

Effects of stimulus salience on touchscreen serial reversal learning in a mouse model of fragile X syndrome

Fragile X syndrome (FXS) is the most common inherited form of intellectual disability in males and the most common genetic cause of autism. Although executive dysfunction is consistently found in humans with FXS, evidence of executive dysfunction in Fmr1 KO mice, a mouse model of FXS, has been inconsistent. One possible explanation for this is that executive dysfunction in Fmr1 KO mice, similar to humans with FXS, is only evident when cognitive demands are high. Using touchscreen operant conditioning chambers, male Fmr1 KO mice and their male wildtype littermates were tested on the acquisition of a pairwise visual discrimination followed by four serial reversals of the response rule. We assessed reversal learning performance under two different conditions. In the first, the correct stimulus was salient and the incorrect stimulus was non-salient. In the second and more challenging condition, the incorrect stimulus was salient and the correct stimulus was non-salient; this increased cognitive load by introducing conflict between sensory-driven (i.e., bottom-up) and task-dependent (i.e., top-down) signals. Fmr1 KOs displayed two distinct impairments relative to wildtype littermates. First, Fmr1 KOs committed significantly more learning-type errors during the second reversal stage, but only under high cognitive load. Second, during the first reversal stage, Fmr1 KOs committed significantly more attempts to collect a reward during the timeout following an incorrect response. These findings indicate that Fmr1 KO mice display executive dysfunction that, in some cases, is only evident under high cognitive load.

Impact of cognitive and behavioural changes on quality of life in Huntington's disease

Huntington's disease (HD) is associated with both cognitive and behavioural changes in addition to movement disorder. We aimed to investigate relationships between self-reported Quality of Life (QoL), motor symptoms, cognitive deficits and behavioural problems in HD. Twenty outpatients with HD (mean age 53.85 years, SD=7.05; mean education 13.30 years, SD=2.49; mean years since motor onset 6.87 years, SD=4.93) were recruited from the Queen Elizabeth Psychiatric Hospital, Birmingham, UK. QoL was assessed using the SF-36 questionnaire. Executive measures were used to assess attention, verbal fluency, working memory and inhibition. Behavioural measures included the Problem Behaviours Assessment-Short Form (PBA-S) to assess depressive symptoms, and the frontal systems behaviour scale (FrsBe) to assess apathy, disinhibition and executive dysfunction. Unified Huntington's Disease Rating Scale motor scores (UHDRS-MS) were also recorded. QoL scores were not related to UHDRS-MS, PBA-S depression scores, or performance on specific executive tasks. However, QoL was lower for patients who exhibited greater apathy and showed more evidence of executive dysfunction in their everyday behaviour as assessed by the FrsBe. Our findings imply that behavioural evidence of apathy and executive problems are closely related to self-reported QoL in HD, and that these factors can impact patients’ wellbeing more than movement disorder.

J14 Cognitive and emotional contributions to quality of life in Huntington's disease

<h3>Background</h3> Patients with HD exhibit cognitive and emotional changes in addition to movement symptoms. Multiple factors are therefore likely to affect patients9 quality of life. <h3>Aims</h3> We aimed to investigate relationships between cognitive and emotional factors and self-reported quality of life in Huntington9s disease. <h3>Methods</h3> Participants were 16 outpatients with Huntington9s disease (mean age 53 years, SD=7.5, range=42–61; mean education 13 years, SD=2.6, range 11–17; mean years since motor onset 6.3 years, SD=5.5, range 2–18), recruited from the Queen Elizabeth Psychiatric Hospital, Birmingham, UK. Quality of Life (QoL) was measured using the SF36. We administered a range of executive tasks (including measures of verbal fluency, working memory and inhibition), and the frontal systems behaviour scale to assess apathy, disinhibition and executive dysfunction. The Interpersonal Reactivity Index was used to assess aspects of empathy and perspective taking, and the Unified Huntington9s Disease Rating Scale motor assessment was carried out. <h3>Results</h3> QoL scores were not related to motor symptom scores, or scores on specific executive tasks. However, QoL was lower for patients who exhibited greater apathy and showed more evidence of executive dysfunction in their everyday behaviour. Of additional interest, we found that disinhibited behaviour was associated with reduced empathic concern. <h3>Conclusions</h3> Deterioration in mood and cognitive function can impact perceived QoL more than movement disorder in HD. Understanding more about the interactions between cognitive, emotional and behavioural changes in HD will be critical in the development and evaluation of future interventions.

Further evidence for executive dysfunction in subjects with RLS from a non-clinical sample

Previous studies exploring cognitive functioning in RLS have either relied on medication free subjects sampled within a clinical context or on subjects with RLS symptoms identified within population samples. However, in contrast to clinical samples, population studies so far have not excluded the use of antidepressants, hypnotics, or RLS relevant medication, and study subjects were exclusively older in age. We therefore report on cognitive functioning in predominantly middle-aged individuals with RLS symptoms sampled from the general population and free of mental disorders and of hypnotic, psychopharmacological, or RLS relevant medication. Participants with RLS symptoms and individually matched controls were identified within the MARS control study, a non-clinical control group study of 550 participants between 18 and 75 years. Cognitive functioning was assessed with the Trail Making Test A and B and a computerized German version of the Wisconsin Card Sorting Test (WCST). Performance was compared between 41 participants with RLS and 133 controls, and between a subgroup of 10 participants with frequent RLS symptoms (≥ 2/week) and 36 matched controls. There was no difference in cognitive functioning for the complete group of participants with RLS and controls. However, participants with frequent RLS symptoms showed impaired performance in the WCST. The results of this study add to the evidence that executive functioning is impaired in individuals with frequent RLS.

Judgements of social inappropriateness in adults with Tourette's syndrome

Introduction. Socially inappropriate behaviour has frequently been reported in Tourette's syndrome (TS), but has not been studied experimentally. The current study was designed to examine the appropriateness of self-disclosures in TS using an emotional self-disclosure task. Methods. Adult participants with TS-alone (20) and matched controls (20) were compared on two social judgement tasks, one examining the regulation of behaviour in an emotional self-disclosure task requiring participants to generate examples of autobiographical events, and the other examining mentalistic judgement of others’ behaviour on a faux pas task. Results. Those with TS-alone and controls showed no group differences for judges’ or participants’ ratings of inappropriateness on the self-disclosure task, although only the self-ratings of the control group corresponded to the judges’ ratings. On the faux pas task, those with TS-alone were impaired relative to controls in detecting socially inappropriate behaviour. There was also some evidence of executive dysfunction in the TS-alone group. Conclusions. TS-alone is linked to a mixed pattern of preserved and impaired performance on social cognition measures, and further work is needed to determine the contributions of social and/or executive contributions to everyday functioning.

Altered patterns of cortical activation in ALS patients during attention and cognitive response inhibition tasks

Since amyotrophic lateral sclerosis (ALS) can be accompanied by executive dysfunction, it is hypothesised that ALS patients will have impaired performance on tests of cognitive inhibition. We predicted that ALS patients would show patterns of abnormal activation in extramotor regions when performing tests requiring the inhibition of prepotent responses (the Stroop effect) and the inhibition of prior negatively primed responses (the negative priming effect) when compared to healthy controls. Functional magnetic resonance imaging was used to measure activation during a sparse sequence block design paradigm investigating the Stroop and negative priming effects in 14 ALS patients and 8 healthy age- and IQ-matched controls. Behavioural measures of performance were collected. Both groups’ reaction times (RTs) reflected the Stroop effect during scanning. The ALS and control groups did not differ significantly for any of the behavioural measures but did show significant differences in cerebral activation during both tasks. The ALS group showed increased activation predominantly in the left middle temporal gyrus (BA 20/21), left superior temporal gyrus (BA 22) and left anterior cingulate gyrus (BA 32). Neither group’s RT data showed clear evidence of a negative priming effect. However the ALS group showed decreased activation, relative to controls, particularly in the left cingulate gyrus (BA 23/24), left precentral gyrus (BA 4/6) and left medial frontal gyrus (BA 6). Greater cerebral activation in the ALS group accompanying the performance of the Stroop effect and areas of decreased activation during the negative priming comparison suggest altered inhibitory processing in ALS, consistent with other evidence of executive dysfunction in ALS. The current findings require further exploration in a larger study.

Recollection deficiencies in patients with major depressive disorder

Neuropsychological research suggests that recognition memory (RM) and recall memory are impaired in patients with a major depressive disorder or a dysphoric mood state. This study examines the proposal that abnormalities in recollection (a form of recall) result from a breakdown in frontal strategic memory processes involved in encoding and retrieval, and executive functions linked to reality monitoring, planning, problem-solving, reasoning and decision-making. We investigated two predictions arising from this theory. Firstly, patients diagnosed with a major depressive disorder (MDD) will display a dissociation between (deficient) recollection and (preserved) familiarity. Secondly, if recollection impairments are indicative of a breakdown in prefrontal strategic memory processes which are dependent, at least in part, on executive processes, then an explicit correlational approach predicts that recollection will be positively associated with the severity of executive dysfunction in MDD patients. The remember/know paradigm was used to investigate RM for words and neutral faces in 16 MDD patients and 16 healthy volunteers, matched for age, gender and estimates of premorbid IQ. Measures of executive function included working memory, reasoning and decision-making. Applying the Dual Process Signal Detection interpretation of the remember/know data, the MDD group displayed significant impairments in RM and recollection rates for both verbal and neutral facial memoranda. In contrast, familiarity-aware rates were preserved. There was no evidence of executive dysfunction in the patient group, and little evidence that recollection rates correlated with executive function. Furthermore, a single process signal detection approach suggested that the MDD patients displayed a reduction in sensitivity for RM and remember rates but not know responses. The criteria for detecting studied from unstudied items, and remembering from knowing, were the same in both patient and healthy control groups. Taken together, these findings are consistent with the view that MDD is marked by a decline in RM, which is underpinned by an impairment in recollection rather than familiarity processes. The extent to which the recollection deficiencies arise from disruption of strategic memory and executive processes requires further investigation.

Evidence of executive dysfunction in extremely obese adolescents: a pilot study

Background Obesity in children and adolescents is 1 of the most urgent and serious health threats confronting the United States. Extremely obese adolescents (body mass index >99th percentile for age and gender) are a unique subgroup of obese youth who are at considerable medical and psychosocial risk. Little is known about the cognitive function of extremely obese adolescents. The present study sought to examine the cognitive performance of a sample of extremely obese adolescents seeking primary treatment for weight loss. Methods Adolescents were recruited during regularly scheduled medical appointments at a children's center for weight management associated with a major children's hospital in the Southeast United States. A computerized battery of cognitive tests was administered to obese adolescents (body mass index >99th percentile; n = 25). Results Obese adolescents exhibited deficits in many cognitive domains, including impairment in attention and executive functions (e.g., mental flexibility, disinhibition) compared with the normative data. Conclusion Although preliminary, these data have provided evidence for specific cognitive deficits in extremely obese adolescents. These findings highlight a need to determine whether early weight loss interventions, such as bariatric surgery, for obese adolescents could potentially prevent or reverse cognitive deficits and/or reduce the risk of future adverse neurocognitive outcome.

Executive functioning in preschool children born very preterm: Relationship with early white matter pathology

Despite evidence for executive dysfunction in school-aged preterm children, less is known about the early development of these difficulties or their underlying neuropathology. This study used prospective longitudinal data from a regional cohort of 88 very preterm and 98 full-term comparison children to examine the executive functioning (EF) of preschool children born very preterm. The relationship between the severity of neonatal cerebral white matter (WM) abnormalities on magnetic resonance imaging (MRI) at term equivalent and children's EF at ages two and four years (corrected age) was examined. At age four, very preterm children with WM abnormalities performed less well than full-term children on the Detour Reaching Box, a measure of behavioral inhibition and cognitive flexibility, even after controlling for child IQ, SES, and medical background. Examination of patterns of EF performance between the ages of 2 and 4 years showed that the performance of all groups improved with age. However, very preterm children with mild and moderate-severe WM abnormalities were characterized by higher rates of consistent performance impairments. These findings support the presence of early and persistent executive difficulties in preschool children born very preterm, and highlight the importance of white matter pathology in the development of executive impairments.

Effects of Hormone Replacement Therapy and Aging on Cognition: Evidence for Executive Dysfunction

ABSTRACT The present study was designed to explore whether the frontal lobe hypothesis of cognitive aging may be extended to describe the cognitive effects associated with estrogen use in postmenopausal women. Postmenopausal estrogen-only users, estrogen + progesterone users, and non-users (60–80 years old), as well as young, regularly cycling women (18–30 years old) completed an item and source memory task. Since source memory is thought to rely more on executive processes than item memory, we hypothesized that aging and estrogen effects would be greater for source memory than for item memory. Neuropsychological tests explored whether the effects of aging and estrogen use were revealed on other tests of frontal lobe function. Results from the experimental task revealed greater aging and estrogen effects for source memory than for item memory, and neuropsychological results revealed aging and estrogen effects on a subset of tests of executive function. Women on estrogen + progesterone therapy did not outperform non-users, suggesting that the addition of progesterone to hormone therapy may mitigate the benefits induced by estrogen use alone. Overall, findings support the hypothesis that estrogen use may temper age-related cognitive decline by helping to maintain functions subserved by the frontal lobes.

Acquired Sociopathy: A Neuropsychological Study of Executive Dysfunction in Violent Offenders

The current research investigated the extent of executive function deficits in a population of 25 violent offenders. The population was separated into primarily instrumental and primarily reactive offenders based on their offence characteristics. Each group was then administered neuro-psychological measures which were considered sensitive to executive function impairment. It was hypothesised that there would be evidence of executive dysfunction in the sample and that in comparison with the primarily instrumental group, the primarily reactive group would show significant impairment on the executive function measures. The results supported these hypotheses; the primarily reactive group was significantly impaired on tasks that assessed higher-order executive functions. The primarily instrumental group was largely intact on executive function measures, although it showed a tendency to be selectively impulsive on several executive function measures depending on how important the task was judged to be. These results suggested that primarily reactive offenders may have difficulty controlling their behaviour (acquired sociopathy) while primarily instrumental offenders may choose not to control their behaviour (selective impulsivity) and may not benefit from behaviourally based treatment. In order to effectively assess and treat violent offenders, consideration of type of violence and integrity of executive function may be important to improve outcomes.