While Attention-deficit/hyperactivity disorder (ADHD) remains one of the most common psychological disorders diagnosed, current understanding of the disorders expression and factors contributing to impairment in early adulthood remains limited. In an effort to better understand current issues with ADHD assessment and treatment in emerging adults, this study aimed to examine relationships between symptoms, executive function (EF), sleep, and impairment. Overall results of this study indicate that together, ADHD symptoms, EF, and sleep account for a significant proportion of variance in impairment. Additionally, results indicate that EF moderates the relationship between ADHD symptoms and impairment, and that sleep may be a protective factor for adults. Specifically, this study found that when compared to individuals reporting more sleep problems, the effect of ADHD symptoms and EF on impairment was much weaker among individuals reporting fewer sleep problems. Understanding the relationship between ADHD symptoms, EF, and sleep is critically important in better understanding adult ADHD and in informing assessment and treatment strategies to more effectively reduce impairment.

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Child maltreatment impacts approximately one in seven children in the United States, leading to many adverse outcomes throughout life. Adolescence is a time period that is critical for the development of self-regulation, as it is when the prefrontal cortex is actively developing. Existing research demonstrates the numerous adverse effects maltreatment may have on self-regulation, which encompasses executive function and emotion regulation abilities. However, there is little research examining how abuse and neglect may differently affect the developmental trajectories of executive function and emotion regulation throughout adolescence and into young adulthood. In the current study, 167 adolescents participated approximately annually at six time points, from ages 14 to 20. At each of the six time points, adolescents completed three executive function tasks as well as self-report questionnaires on their emotion regulation abilities and strategies. Information on maltreatment experienced from ages 1 to 13 was collected when the adolescents were approximately 18 to 20 years of age. Conditional growth curve models were utilized to test the differential effects of abuse and neglect on the growth trajectories of executive function abilities and emotion regulation difficulties and strategy use. The results revealed that neglect was associated with developmental changes in working memory abilities, such that greater amounts of neglect were associated with slower increases in working memory abilities across ages 14 to 20. Further, abuse was associated with developmental changes in difficulties in emotion regulation abilities, such that greater amounts of abuse were associated with larger increases in difficulties in emotion regulation abilities from ages 14 to 20. Finally, neglect was associated with the initial level (at age 14) of difficulties in emotion regulation abilities, such that greater levels of neglect were associated with higher initial levels of difficulties in emotion regulation abilities as compared to individuals with lesser amounts of experienced neglect. These findings suggest that working memory development during adolescence into young adulthood may be more vulnerable to childhood neglect and that both abuse and neglect in childhood may have adverse impacts on the development of emotion regulation abilities. / M.S. / Child maltreatment impacts approximately one in seven children in the United States, leading to many adverse outcomes throughout life. Adolescence is a time period that is critical for the development of self-regulation, which encompasses executive function and emotion regulation abilities. Existing research demonstrates the numerous adverse effects maltreatment may have on self-regulation. However, there is little research examining how abuse and neglect may differently affect the developmental trajectories of executive function and emotion regulation throughout adolescence and into young adulthood. In the current study, 167 adolescents participated approximately annually at six time points, from ages 14 to 20. At each of the six time points, adolescents completed three executive function tasks as well as self-report questionnaires on their emotion regulation abilities and strategies. Information on maltreatment experienced from ages 1 to 13 was collected when the adolescents were approximately 18 to 20 years of age. The results revealed that greater amounts of neglect were associated with slower increases in working memory abilities across ages 14 to 20. Further, greater amounts of abuse were associated with larger increases in difficulties in emotion regulation abilities from ages 14 to 20. Finally, neglect was associated with difficulties in emotion regulation abilities at age 14, such that greater levels of neglect were associated with higher levels of difficulties in emotion regulation abilities at age 14 compared to individuals with lesser amounts of experienced neglect. These findings suggest that working memory development during adolescence into young adulthood may be more vulnerable to childhood neglect and that both abuse and neglect in childhood may have adverse impacts on the development of emotion regulation abilities.

Hemispherectomy has gained widespread endorsement as a useful technique for treating seizures in patients with cerebral hemispheric dysfunction. Following this procedure, most patients experience seizure-freedom or a substantial decrease in the number of seizures occurring. Regarding other areas of functioning, patients generally maintain the same level of intelligence, language abilities, motor functioning, and visual ability, and experience improvements in behavioral disturbances and social skills. However, the current outcome literature lacks information regarding the effect of hemispherectomy on executive function. The purpose of this study is to evaluate executive function in pediatric patients with intractable epilepsy following a hemispherectomy. The parents of children who had undergone this surgical intervention completed the Behavior Rating Inventory of Executive Function (BRIEF; Gioia, Isquith, Guy, and Kenworthy, 2002) and their children's scores were compared to those of children with epilepsy treated with anticonvulsant medications (AEDs) only. The impact of clinical variables (i.e. age at time of surgery, lateralization of hemispherectomy, and amount of time since surgery) on BRIEF scores were also examined. Results indicated that children undergoing a hemispherectomy produced lower scores (less impaired) on several of the BRIEF scales as compared to those taking AEDs only. The left and right hemispherectomy group differed only on a subscale measuring behavioral inhibition, with the right hemispherectomy group producing a higher mean (meaning more impairment). Several BRIEF scores in the aggregate hemispherectomy group were positively correlated with time since surgery, such that longer post-operative periods were associated with poorer performances on the BRIEF. Several BRIEF measures were negatively correlated with age at time of surgery, suggesting that younger patients fared worse on the BRIEF than older patients.

This study examined processing speed and executive function late effects in survivors of pediatric ALL (hereafter referred to as Survivors). Late effects are long-term, treatment-related health problems associated with the neurotoxic side-effect of cancer treatment on brain development. Processing speed —mental and motor speed with which a person can solve nonverbal problems — was estimated via an composite of processing speed attained from several measures of processing speed. Executive function — a collection of processes orchestrated in the performance of purposeful, goal-directed behavior — was measured using the Parent and Teacher forms of the Behavior Rating Inventory of Executive Function (BRIEF). This study also explored the effect of previously identified risk factors for processing speed and executive function late effects. Finally, executive function late effects were further explored via the use of performance-based measures, including the Tower and Trail Making (Condition 4) tests of the Delis-Kaplan Executive Function System (D-KEFS). Hypotheses included (1) Survivors would demonstrate significantly poorer processing speed; (2) late effects risk factor variables (i.e., greater elapsed time since completion of treatment, lower age at diagnosis, and higher intensity of treatment) would predict poorer processing speed; (3) female gender would predict poorer processing speed; (4) parents and teachers would demonstrate both low interrater agreement (Hypothesis 4a) and differ significantly in the severity (Hypothesis 4b) of their ratings of Survivor executive function; (5) parent and teacher ratings of executive function would indicate significantly poorer Survivor metacognition (Hypothesis 5a), whereas Survivor behavioral regulation would not differ significantly (Hypothesis 5b); (6) risk factor variables would predict poorer Parent and Teacher ratings of Survivor metacognition; (7) female gender would predict poorer Parent and Teacher ratings of Survivor metacognition; (8) survivor processing speed and Parent and Teacher ratings of executive function would exhibit a positive relationship; and (9) poorer Survivor processing speed would predict poorer parent and teacher ratings of executive function. Results provided support for hypothesis 1 and 5a. Partial support was obtained for hypotheses 4a, 4b, and 7. Hypotheses 2, 3, 5b, 6, 8, and 9 were not supported. / text

Children at a certain age often have difficulty in flexibly shifting attention between different representational schemes. One example of such cognitive inflexibility occurs in the Dimensional Change Card Sorting (DCCS) task in which 3-year-old children have difficulty switching between sorting dimensions. For instance, after initially sorting the cards by one dimension (e.g., colour) they are unable to sort the cards by a second dimension (e.g., shape). This finding has been primarily associated with problems in attention or inhibition. The present study investigated the role of perceptual information on children’s dimensional shift abilities by manipulating the perceptual characteristics of both task-relevant (the colour or shape of the images on the cards) and task-irrelevant (the background colour or shape of the actual cards themselves) aspects of the task materials between the pre- and post-switch experimental phases. Across three experiments better performance was observed when either task-relevant or task-irrelevant information was changed, with this improved performance occurring when these changes were salient enough to induce a stimulus novelty effect. Experiment 4 investigated yet another perceptual feature of the task; the degree of stimulus realism (abstractness) on children’s cognitive flexibility. Children successfully sorted the cards when three-dimensional stimuli were used but perseverated when using two-dimensional cards, providing evidence for the role of representational status of the stimuli in influencing children’s dimensional switching. Manipulations made to increase the salience of the task material as well as those resulting in reduction of similarity between the two phases of the tasks (or increased novelty) were used to enhance children’s cognitive flexibility. Overall, these findings highlight the critical role played by the perceptual information of the overall experimental context, and have important implications for theories of cognitive flexibility.

Children at a certain age often have difficulty in flexibly shifting attention between different representational schemes. One example of such cognitive inflexibility occurs in the Dimensional Change Card Sorting (DCCS) task in which 3-year-old children have difficulty switching between sorting dimensions. For instance, after initially sorting the cards by one dimension (e.g., colour) they are unable to sort the cards by a second dimension (e.g., shape). This finding has been primarily associated with problems in attention or inhibition. The present study investigated the role of perceptual information on children’s dimensional shift abilities by manipulating the perceptual characteristics of both task-relevant (the colour or shape of the images on the cards) and task-irrelevant (the background colour or shape of the actual cards themselves) aspects of the task materials between the pre- and post-switch experimental phases. Across three experiments better performance was observed when either task-relevant or task-irrelevant information was changed, with this improved performance occurring when these changes were salient enough to induce a stimulus novelty effect. Experiment 4 investigated yet another perceptual feature of the task; the degree of stimulus realism (abstractness) on children’s cognitive flexibility. Children successfully sorted the cards when three-dimensional stimuli were used but perseverated when using two-dimensional cards, providing evidence for the role of representational status of the stimuli in influencing children’s dimensional switching. Manipulations made to increase the salience of the task material as well as those resulting in reduction of similarity between the two phases of the tasks (or increased novelty) were used to enhance children’s cognitive flexibility. Overall, these findings highlight the critical role played by the perceptual information of the overall experimental context, and have important implications for theories of cognitive flexibility.

Children born very preterm (VPT) are known to be at high risk of under-achievement in mathematics. However the nature of these difficulties is poorly understood. In this study, a regionally representative cohort of 102 children born VPT and a comparison group of 108 children born full term (FT) during 1998-2000 were followed from birth to nine years. At age nine, children were tested using the Woodcock-Johnson III maths fluency subtest, and teacher reports of mathematical achievement and curriculum-based (numeracy project) achievement data were collected. The data was analysed using group comparisons and multiple regression. Parent and teacher ratings of executive function at age six were included as predictors. Findings indicated that children born VPT had elevated rates of mathematical difficulties across all measures including the standardised and curriculum-based measures, and teacher ratings. They also had higher rates of mathematical learning disability. With the exception of curriculum-based measures, these results remained significant even after controlling for socioeconomic status and severe neurodevelopmental impairment. Children born VPT showed particular difficulty using operational strategies, rather than with factual knowledge, and this effect was most marked for addition and multiplication. As well as difficulties in mathematics, children born VPT also showed more difficulty than children born FT in almost all areas of executive function. Difficulties with working memory at age six were significantly associated with poor performance in aspects of curriculum-based measures at age nine.

Based on classic and contemporary theories of cognitive development by Vygotsky, Luria, and Zelazo and colleagues, the main objective of the present study was to systematically evaluate the association between different aspects of language, namely semantic and syntactic knowledge, and specific executive functioning (EF) abilities (working memory, inhibition, and flexibility) in preschoolers. Sixty-seven children age 3-5 years were administered a battery of EF and language measures. A latent variable approach was used to estimate performance on EF tasks. A two-factor model consisting of working memory/inhibition (WM/INH) and flexibility provided the best fit for the data. The results showed that syntactic ability uniquely explained a significant amount of variance in both WM/INH and flexibility over and above age and semantic ability. Furthermore, children’s complex syntax scores predicted their performance on complex blocks of flexibility tasks. These findings provide preliminary evidence for the association between children’s understanding of the structure of language and EF. / Graduate / 0620 / eyeung@uvic.ca

In an era where the diagnosis of attention deficit/hyperactivity disorder (ADHD) is as high as 7% in school-aged children, the search for causes and preventions has never been more important. Current research indicates a positive relationship between bilingualism, particularly native bilingualism, and executive function in normally developing individuals. This study served to examine the potential relationship between bilingual education in a public school setting and the presence of ADHD symptoms in that school's students. This was a comparative analysis of students in a South Florida School District's two-way immersion program with the national average in terms of frequency of ADHD symptoms using the NICHQ Vanderbilt Assessment Scale and the Swanson, Nolan, and Pelham (SNAP). The results did not show any significant differences between groups in terms of language history, gender, race, or family structure.