A comprehensive review of the published work arising from Skinner's (1953) chapter on self-control was undertaken. This was thought to be necessary because many of the papers were of poor quality, and the existing reviews were found to be inadequate. It was concluded that the effects of motivation on self-control had received little attention from the majority of operant workers. In particular, the role of delayed rewards had been neglected. Therefore, the experimental part of the thesis was devoted to the investigation of the effects of a delayed reward on the use of an unpleasant controlling response. It was decided that this could be done most economic¬ally by using an experimental analogue of a self-control situation. A theoretical model of self-control was described and an analogue was devised. Three experiments were performed, during the course of which the analogue was refined and several hypotheses derived from the model were tested. It was found that although the analogue was partially successful, it did not provide adequate experimental control over relevant independent variables. It also resulted in considerable subject wastage. The results of the final experiment indicated that both the subjective value of the reward and the expectancy of obtaining it, influenced the use of an unpleasant controlling response. In fact, value and expectancy appeared to have complementary effects. The theoretical and practical significance of these findings were discussed.

abstract: A substantial amount of research demonstrates that preschoolers' phonological awareness skills are a robust predictor of children's later decoding ability. Several investigators examined performance of children with speech sound impairment (SSI), defined as inaccurate production of speech sounds in the absence of any etiology or communication impairment, on phonological awareness tasks. Investigators found that children with SSI scored below their typically developing peers (TD) on phonological awareness tasks. In contrast, others found no differences between groups. It seems likely that differences in findings regarding phonological awareness skills among children with SSI is the fact that there is considerable heterogeneity among children with SSI (i.e., speech errors can either be a phonological or articulation). Phonology is one component of a child's language system and a phonological impairment (SSI-PI) is evident when patterns of deviations of speech sounds are exhibited in a language system. Children with an articulation impairment (SSI-AI) produce speech sound errors that are affected by the movements of the articulators, not sound patterns. The purpose of the study was to examine whether or not children with SSI-PI are at greater risk for acquiring phonological awareness skills than children with SSI-AI. Furthermore, the phonological awareness skills of children with SSI-PI and SSI-AI were compared to those of their typical peers. In addition, the role of executive function as well as the influence of phonological working memory on phonological awareness task performance was examined. Findings indicate that the SSI-PI group performed more poorly on an assessment of phonological awareness skills than the SSI-AI and TD groups. The SSI-PI group performed significantly more poorly on tasks of executive function and phonological working memory than the TD group. The results of this study support the hypothesis that children with SSI-PI may be more vulnerable to difficulties in reading than children with SSI-AI and children with TD. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2015

abstract: Research suggests that some children with primary language impairment (PLI) have difficulty with certain aspects of executive function; however, most studies examining executive function have been conducted using tasks that require children to use language to complete the task. As a result, it is unclear whether poor performance on executive function tasks was due to language impairment, to executive function deficits, or both. The purpose of this study is to evaluate whether preschoolers with PLI have deficits in executive function by comprehensively examining inhibition, updating, and mental set shifting using tasks that do and do not required language to complete the tasks. Twenty-two four and five-year-old preschoolers with PLI and 30 age-matched preschoolers with typical development (TD) completed two sets of computerized executive function tasks that measured inhibition, updating, and mental set shifting. The first set of tasks were language based and the second were visually-based. This permitted us to test the hypothesis that poor performance on executive function tasks results from poor executive function rather than language impairment. A series of one-way analyses of covariance (ANCOVAs) were completed to test whether there was a significant between-group difference on each task after controlling for attention scale scores. In each analysis the between-group factor was group and the covariate was attention scale scores. Results showed that preschoolers with PLI showed difficulties on a broad range of linguistic and visual executive function tasks even with scores on an attention measure covaried. Executive function deficits were found for linguistic inhibition, linguistic and visual updating, and linguistic and visual mental set shifting. Overall, findings add to evidence showing that the executive functioning deficits of children with PLI is not limited to the language domain, but is more general in nature. Implications for early assessment and intervention will be discussed. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2015

abstract: Adults with a history of traumatic brain injury (TBI) often show deficits in executive functioning, which include the ability to inhibit, switch, and attend to task relevant information. These abilities are also essential for language processing in bilinguals, who constantly inhibit and switch between languages. Currently, there is no data regarding the effect of TBI on executive function and language processing in bilinguals. This study used behavioral and eye-tracking measures to examine the effect of mild traumatic brain injury (mTBI) on executive function and language processing in Spanish-English bilinguals. In Experiment 1, thirty-nine healthy bilinguals completed a variety of executive function and language processing tasks. The primary executive function and language processing tasks were paired with a cognitive load task intended to simulate mTBI. In Experiment 2, twenty-two bilinguals with a history of mTBI and twenty healthy control bilinguals completed the same executive function measures and language processing tasks. The results revealed that bilinguals with a history of mTBI show deficits in specific executive functions and have higher rates of language processing deficits than healthy control bilinguals. Additionally, behavioral and eye-tracking data suggest that these language processing deficits are related to underlying executive function abilities. This study also identified a subset of bilinguals who may be at the greater risk of language processing deficits following mTBI. The findings of this study have a direct impact on the identification of executive function deficits and language processing deficits in bilinguals with a history mTBI. / Dissertation/Thesis / Doctoral Dissertation Speech and Hearing Science 2015

abstract: Background: Stroke is a leading cause of long-term disability in the United States (US). Assisted Cycling Therapy (ACT) incorporates the use of an electric motor to enhance the rotations per minute (rpm). ACT of about 80 rpm, has been associated with improvements in motor, cognitive, and clinical function. The acute effects of ACT on motor and cognitive function of persons with stroke induced deficits have not been investigated. Purpose: To compare the acute effects of ACT, voluntary cycling (VC), and no cycling (NC) on upper and lower extremity motor function and executive function in adults with chronic stroke (age: 60 ± 16 years; months since stroke: 96 ± 85). Methods: Twenty-two participants (gender: female = 6, male = 16; types: ischemic = 12, hemorrhagic = 10; sides: left lesion = 15, right lesion = 7) completed one session of ACT, one session of VC and one session of NC on separate days using a 3 x 3 crossover design. Results: ACT lead to greater improvements in lower and upper extremity function on the paretic and non-paretic side than VC or NC (all p < 0.05), except in the non-paretic lower extremity where ACT and VC produced similar improvement (both p < 0.05). ACT and VC, but not NC, were associated with improvements in inhibition (p < 0.05). A positive relationship between cadence and motor function (P < 0.05) was found. Ratings of perceived exertion shared an inverted-U shaped relationship with measures of processing speed (p < 0.05) and a negative linear relationship with measures of executive function (p < 0.05). Conclusion: ACT appears to benefit paretic and non-paretic motor function globally whereas the benefits of VC are more task specific. Faster cycling cadence was associated with greater improvements in global motor function. ACT and VC seem to carry similar acute benefits in inhibition. / Dissertation/Thesis / Doctoral Dissertation Physical Activity, Nutrition and Wellness 2017

abstract: Alexithymia is a personality trait characterized by a diminished ability to identify and describe feelings, as well as an inability to distinguish physical symptoms associated with emotional arousal. Alexithymia is elevated in both patients with epilepsy (a neurologically-based seizure disorder) and psychogenic nonepileptic seizures (PNES; a psychological condition mimicking epilepsy); however, different neuropsychological processes may underlie this deficit in the two groups. To expand on previous research considering factors contributing to alexithymia in these populations, we examined the extent to which scores on the Toronto Alexithymia Scale (TAS-20) were predicted by performance on measures of executive and language functioning. We studied 138 PNES and 150 epilepsy patients with video-EEG confirmed diagnoses. Neuropsychological tests were administered to assess executive functioning (interference scores of the Stroop Color-Word Test and Part B of the Trail Making Test) and language functioning (Animals, Controlled Oral Word Association Test, and Boston Naming Test). Hierarchical linear regressions revealed that the relationships between disparate neuropsychological domains and alexithymia were not moderated by diagnosis of PNES or epilepsy. Multiple regression analyses within each group demonstrated that phonemic verbal fluency and response inhibition were significant predictors of alexithymia in epilepsy. Thus, alexithymia may reflect impairments in language and aspects of executive functioning in both PNES and epilepsy. / Dissertation/Thesis / Masters Thesis Psychology 2017

Orientadores: Maria Augusta Santos Montenegro, Catarina Abraão Guimarães / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-23T02:13:36Z (GMT). No. of bitstreams: 1 Dutra_ViviandeFreitas_M.pdf: 934165 bytes, checksum: 8b4ab28e6d611333899e520d12584954 (MD5) Previous issue date: 2013 / Resumo: A fenilcetonúria é um erro inato do metabolismo, com incidência entre 1:10000 e 1:15000 nascidos vivos. Trata-se de uma doença de herança autossômica recessiva, caracterizada pela deficiência da enzima hepática fenilalanina hidroxilase ou de seu co-fator tetraidrobiopterina, que, na rota metabólica normal, são responsáveis por converter a fenilalanina em tirosina. O acúmulo de fenilalanina é tóxico ao Sistema Nervoso Central. O défict nos níveis de tirosina leva ao desequilíbrio metabólico que pode causar hipotonia, irritabilidade, letargia, tonturas, microcefalia, características autistas, défict cognitivo e atraso de desenvolvimento. O tratamento é baseado na dieta restrita em fenilalanina. Quando a dieta é iniciada precocemente, o prognóstico cognitivo é bom e os pacientes apresentam QI dentro da média. Embora não haja rebaixamento de QI, alguns estudos mostram que os resultados de avaliação neuropsicológica dos pacientes são piores do que irmãos e pares sem a doença, especialmente com relação a funções executivas. O objetivo deste trabalho foi avaliar e comparar o desempenho de crianças e adolescentes com fenilcetonúria tratados em um Serviço de Referência no Brasil em provas neuropsicológicas de memória e funções executivas, e comparar com aquele apresentado por pares sem a doença. Participaram do estudo 12 crianças e adolescentes com fenilcetonúria leve, oito com hiperfenilalaninemia permanentemente e uma com fenilcetonúria clássica. A idade do grupo caso índice variou entre seis e 15 anos (m=9,52±2,82). O grupo controle foi formado por 21 crianças e adolescentes com idade entre seis e 14 anos (m=9,19±2,84), recrutados em uma escola de rede municipal. Como instrumento para a avaliação neuropsicológica foi utilizada a Escala de Inteligência Wechsler para crianças (WISC-III, 2002) e uma bateria para avaliação de funções executivas, incluindo o Teste de Trilhas, Teste de aprendizagem verbal de Rey, Teste de aprendizagem visual de Rey, teste de fluência verbal FAS e categoria "animais", teste de Stroop e Torre de Hanói. Os dados foram armazenados e analisados com programa estatístico SPSS - Statistic Package for Social Sciences, versão 13.5, considerando o nível de significância de 5%. Não foram encontradas diferenças significativas entre o desempenho do grupo de pacientes e o grupo controle, para nenhum dos achados neuropsicológicos. Apenas uma criança neste estudo apresentou diagnóstico de PKU clássica, a forma da doença com pior prognostico cognitivo. A média de idade de diagnóstico dos participantes foi de 35 dias e 75% dos participantes apresentaram resultados de exame de PHE<8,0 no ano anterior à avaliação neuropsicológica. Os achados concordam com a literatura que indica a importância do tratamento para garantir um bom desenvolvimento cognitivo. Futuros estudos podem avaliar também funções não executivas, e estudos colaborativos entre diferentes centros de tratamento podem fornecer uma amostra mais significativa da população estudada / Abstract: Phenylketonuria is an autossomal recessive metabolic disease caused by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase which makes it nonfunctional. It is one of the most common inborn errors of metabolism, with an incidence of 1:10000 to 1:15000 live births. Accumulation of PHE is toxic to the central nervous system. Low levels of tyrosine add to the metabolic abnormality and patients may present hypotonia, irritability, lethargy, dizziness, microcephaly, autistic features, cognitive impairment and developmental delay. The standard treatment is based on a lifelong diet with low levels of phenylalanine. When PKU restricted diet is started early in life, the cognitive outcome is excellent, and patients have normal IQ. Although there is no cognitive impairment, some studies showed that their neuropsychological scores might be lower than the ones of their peers and siblings, especially regarding executive functions. The objective of this study was to evaluate the neuropsychological performance of children and adolescents with the different types of hyperphenylalaninemia treated at a tertiary center in Brazil and compare with a control group with similar age and socioeconomic level. 12 children and teenagers with mild PKU, eight with HPA and one with classic PKU were evaluated. Age ranged between six and 15 years (m=9,52±2,82). Control group were formed by 21 non-pku children and teenagers with ages between six and 14 years (m=9,19±2,84), recruited in a public school. Neuropsychological evaluation was performed using the Wechsler Inteligence Scale for Children-III (WISC-III, Stroop Test, Rey Auditive Verbal Learning Test (RAVLT), Rey Visual Design Learning Test (RVDLT),Trail Making Test (TMT), Verbal Fluency Test (categorie: animals and letters F,A,S) and Hanoi Tower. This study was approved by the Ethical Committee of our institution. Statistical analysis was performed using the Statistical Package for Social Sciences for Personal Computer (SPSS/PC), Version 13.5; with a level of significance of 0.05. There was no difference regarding the neuropsychological findings between both the hyperphenylalaninemia and mild phenylketonuria groups and control group. One children in this study had classic PKU. Mean diagnostic age was 35 days and 75% of participant's present PHE concentrations < 8,0 mg/dl. These findings are in concordance to literature that indicates the importance of dietetic treatment for an adequate cognitive outcome. Further research could also evaluate non-executive functions and collaborative studies between different centers could provide a larger sample size / Mestrado / Ciencias Biomedicas / Mestra em Ciências Médicas

The ease at which individuals acquire a second language is astounding. Individuals are capable of learning a second language at any point through out their lifespan, although it is easier to learn a second language early in life. With increasing knowledge about linguistic neural processing and the brain’s capacity for plasticity, the research on bilingualism has increased substantially. Researchers have become increasingly more interested in the long-term effects of acquiring a second language, especially the enhancement of executive function (EF). This enhancement, also known as bilingual advantage, has been studied for a range of EFs, including inhibition, attention, problem solving, and reasoning. Although this effect was first demonstrated in bilingual children, researchers have extended the quest for understanding to young, middle, and older adults; however, the research findings are mixed for young adults. In order clarify these mixed results, the age of second language acquisition has been included as an experimental variable, producing three relevant groups: early bilinguals, late bilinguals, and monolinguals. There are several ways in which EFs can be measured, including behavioral rating scales, computerized cognitive tasks with behavioral outcomes (i.e., response times and accuracy), and computerized event-related potential cognitive tasks. A novel multi-level approach to measuring the bilingual advantage was developed and used as a framework for the current dissertation; i.e., the bilingual advantage was measured at three levels of measurement. This approach predicts that more complex levels of measurement (i.e., executive behaviors) would produce null findings between the three groups, while differences between early bilinguals and the other two groups would be predicted for less complex levels of measurement (i.e., neurophysiological markers). This approach predicts mixed results for levels of measurement that involve moderate complexity (e.g., computerized tasks of EF). Early bilinguals, late bilinguals, and monolinguals were compared across three hierarchical levels of measurement: (i) executive behaviors; (ii) information processing (i.e., computerized tasks of EF); and (iii) neurophysiology (i.e., event-related potential paradigm). Findings generally support the multi-level approach: no differences were found at the executive behavior level, limited and mixed differences were found at the information processing level, and differences between groups were found at the neurophysiological level. / Graduate

Objective: This work consisted of three research projects bridged by their focus on a multivariate assessment of executive functions in research and practice: (a) a systematic review and re-analysis of latent variable studies on executive function test batteries, (b) a confirmatory factor analysis (CFA) of the Delis-Kaplan Executive Function System (D-KEFS), the most commonly administered executive function test battery in clinical practice, and (c) the derivation of multivariate base rates for the D-KEFS, offering a psychometric resource with direct applications to clinical practice. Method: Systematic review. The systematic review identified 45 eligible samples (N=9,498 participants, mean age range: 3.01-74.40 years-old) and 21 correlation matrices eligible for re-analysis, comparing seven competing models including the most commonly evaluated factors: updating/working memory, inhibition, and shifting. Model results were summarized based on the mean percent accepted (i.e., mean rate at which models both properly converged and met fit thresholds: CFI≥.90/RMSEA≤.08). CFA. Using adults from the D-KEFS normative sample (N=425; 20-49 years-old), eight alternative measurement models were evaluated for a subset of D-KEFS tests. Factors from the accepted measurement model predicted three tests measuring constructs less often evaluated in the executive function literature: abstraction, reasoning, and problem solving. Base rates. The frequency of low scores occurring among the D-KEFS normative sample (N=1,050; 16-89 years-old) was calculated for the full D-KEFS and two brief batteries using stratifications for age, education, and intelligence. Results: Systematic review. The most often accepted models varied by age (preschool=one/two-factor; school-age=two/three-factor; adolescent/adult=three/nested-factor; older adult=two/three-factor), and most frequently included updating/working memory, inhibition, and shifting factors. The nested-factor and three-factor models were accepted most often and at similar rates among adult samples: 33-34% and 25-32%, respectively. No model was accepted most often for child/adolescent samples, but those with shifting differentiated garnered less support. CFA. A three-factor model including inhibition, shifting, and fluency fit the data well (CFI=0.938; RMSEA=0.047), although a two-factor model merging shifting/fluency fit similarly well (CFI=0.929; RMSEA=0.048). A bifactor model fit best (CFI=0.977; RMSEA=0.032), but rarely converged. Shifting best predicted tests of reasoning, abstraction, and problem solving (p<0.05; R2=0.246-0.408). Base rates. Low scores, based on commonly used clinical cutoffs, occurred frequently among healthy adults. For a three-test, four-test, and full D-KEFS battery, 62.8%, 71.8%, and 82.6% obtained ≥1 score(s) ≤16th percentile, respectively, and 36.1%, 42.0%, 50.7%, obtained ≥1 score(s) ≤5th percentile, respectively. The frequency of low scores increased with lower intelligence and fewer years of education. Discussion: The systematic review effort did not identify a definitive model of executive functions for either adults or children/adolescents, demonstrating the continued need to re-evaluate the conceptualization and measurement of this construct in future research. The D-KEFS CFA offers some evidence of clinical measures capturing theoretical constructs, but is not directly translatable into clinical practice; while the multivariate base rates are useful to clinicians, but do not bridge theory and assessment. This research reaffirms the elusive nature of executive functions in both research and clinical spheres, and represents a step forward in an enduring scientific process towards a true understanding of this mysterious construct. / Graduate / 2018-07-24

Objective: Executive functions govern our ability to navigate complex and novel situations in day-to-day life. There is increased interest on environmental influences that may cause changes to executive functioning. The current thesis involves two studies examining the derivation and performance of an executive behaviour screener from the Behavioral Assessment System for Children (BASC-2-PRS; Reynolds & Kamphaus, 2004) on two different adolescent samples using a previously derived four-factor model of executive functioning (Garcia-Barrera et al., 2011, 2013). Participants and Methods: Study 1. BASC-2 PRS standardization data consisting of a demographically matched American sample of 2722 12-21 year olds was obtained. The screener was derived using 25 items assigned a priori to each executive factor. Confirmatory factor analysis (CFA), invariance testing, and multiple indicators multiple causes (MIMIC) models were used to evaluate the screener. Study 2. The screener was applied to a previously collected sample of 479 elite adolescent hockey players from Canada with or without a history of concussion, followed through a single season of play. CFA, invariance testing, and MIMIC models were used to evaluate the screener and the hockey sample was compared to the standardization sample. Results: Study 1. Acceptable-to-good reliability was obtained for all factors (α = .75-.89). The four-factor model was the best fit to the data (CFI = .990, TLI = .989, RMSEA = .037). Configural, metric, and scalar but not latent mean invariance was shown for sex. Age-related uniform differential item functioning (DIF) and SES-related uniform and non-uniform DIF were shown. Standardized norms for use in clinical settings were created. Study 2. Acceptable-to-good reliability was shown for 3 factors (α = .72-.85). Emotional Control showed poor reliability (α = .58). The four-factor model was the best fit to the data (CFI = .991, TLI = .990, RMSEA = .026). Configural, metric, and scalar but not latent mean invariance was shown between the two samples. Uniform and non-uniform DIF were not observed for those with an increasing number of past concussions. Conclusions: Findings support the four-factor model measured through the screener in adolescence. Females and hockey players demonstrate fewer executive behaviour problems overall. Sex, age, and SES may influence the interpretation of factor scores. Continued exploration and development of the screener is suggested. / Graduate / 2018-09-27