860 resultados para Cognition in adolescence.


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Disturbances of the cholesterol metabolism are associated with Alzheimer's disease (AD) risk and related cerebral pathology. Experimental studies found changing levels of cholesterol and its metabolites 24S-hydroxycholesterol (24S-OHC) and 27-hydroxycholesterol (27-OHC) to contribute to amyloidogenesis by increasing the production of soluble amyloid precursor protein (sAPP). The aim of this study was to evaluate the relationship between the CSF and circulating cholesterol 24S-OHC and 27-OHC, and the sAPP production as measured by CSF concentrations of sAPP forms in humans. The plasma and the CSF concentrations of cholesterol, 24S-OHC and 27-OHC, and the CSF concentrations of sAPPα, sAPPβ, and Aß1-42 were assessed in subjects with AD and controls with normal cognition. In multivariate regression tests including age, gender, albumin ratio, and apolipoprotein E (APOE)ε4 status CSF cholesterol, 24S-OHC, and 27-OHC independently predicted the concentrations of sAPPα and sAPPβ. The associations remained significant when analyses were separately performed in the AD group. Furthermore, plasma 27-OHC concentrations were associated with the CSF sAPP levels. The results suggest that high CSF concentrations of cholesterol, 24S-OHC, and 27-OHC are associated with increased production of both sAPP forms in AD.

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The aim of this study was to assess the usefulness of virtual environments representing situations that are emotionally significant to subjects with eating disorders (ED). These environments may be applied with both evaluative and therapeutic aims and in simulation procedures to carry out a range of experimental studies. This paper is part of a wider research project analyzing the influence of the situation to which subjects are exposed on their performance on body image estimation tasks. Thirty female patients with eating disorders were exposed to six virtual environments: a living-room (neutral situation), a kitchen with highcalorie food, a kitchen with low-calorie food, a restaurant with high-calorie food, a restaurant with low-calorie food, and a swimming-pool. After exposure to each environment the STAI-S (a measurement of state anxiety) and the CDB (a measurement of depression) were administered to all subjects. The results show that virtual reality instruments are particularly useful for simulating everyday situations that may provoke emotional reactions such as anxiety and depression, in patients with ED. Virtual environments in which subjects are obliged to ingest high-calorie food provoke the highest levels of state anxiety and depression.

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Despite that cognitive impairment is a known early feature present in multiple sclerosis (MS) patients, the biological substrate of cognitive deficits in MS remains elusive. In this study, we assessed whether T1 relaxometry, as obtained in clinically acceptable scan times by the recent Magnetization Prepared 2 Rapid Acquisition Gradient Echoes (MP2RAGE) sequence, may help identifying the structural correlate of cognitive deficits in relapsing-remitting MS patients (RRMS). Twenty-nine healthy controls (HC) and forty-nine RRMS patients underwent high-resolution 3T magnetic resonance imaging to obtain optimal cortical lesion (CL) and white matter lesion (WML) count/volume and T1 relaxation times. T1 z scores were then obtained between T1 relaxation times in lesion and the corresponding HC tissue. Patient cognitive performance was tested using the Brief Repeatable Battery of Neuro-psychological Tests. Multivariate analysis was applied to assess the contribution of MRI variables (T1 z scores, lesion count/volume) to cognition in patients and Bonferroni correction was applied for multiple comparison. T1 z scores were higher in WML (p < 0.001) and CL-I (p < 0.01) than in the corresponding normal-appearing tissue in patients, indicating relative microstructural loss. (1) T1 z scores in CL-I (p = 0.01) and the number of CL-II (p = 0.04) were predictors of long-term memory; (2) T1 z scores in CL-I (β = 0.3; p = 0.03) were independent determinants of long-term memory storage, and (3) lesion volume did not significantly influenced cognitive performances in patients. Our study supports evidence that T1 relaxometry from MP2RAGE provides information about microstructural properties in CL and WML and improves correlation with cognition in RRMS patients, compared to conventional measures of disease burden.

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Background: The combined serum creatinine (SCreat) and cystatin C (CysC) CKD-EPI formula constitutes a new advance for glomerular filtration rate (GFR) estimation in adults. Using inulin clearances (iGFRs), the revised SCreat and the combined Schwartz formulas, this study aims to evaluate the applicability of the combined CKD-EPI formula in children. Method: 201 iGFRs for 201 children were analyzed and divided by chronic kidney disease (CKD) stages (iGFRs ≥90 ml/min/1.73 m(2), 90 > iGFRs > 60, and iGFRs ≤59), and by age groups (<10, 10-15, and >15 years). Medians with 95% confidence intervals of bias, precision, and accuracies within 30% of the iGFRs, for all three formulas, were compared using the Wilcoxon signed-rank test. Results: For the entire cohort and for all CKD and age groups, medians of bias for the CKD-EPI formula were significantly higher (p < 0.001) and precision was significantly lower than the solely SCreat and the combined SCreat and CysC Schwartz formulas. We also found that using the CKD-EPI formula, bias decreased and accuracy increased while the child age group increased, with a better formula performance above 15 years of age. However, the CKD-EPI formula accuracy is 58% compared to 93 and 92% for the SCreat and combined Schwartz formulas in this adolescent group. Conclusions: The performance of the combined CKD-EPI formula improves in adolescence compared with younger ages. Nevertheless, the CKD-EPI formula performs more poorly than the SCreat and the combined Schwartz formula in pediatric population. © 2013 S. Karger AG, Basel.

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The Cognitive Performance Scale (CPS) was initially designed to assess cognition in long term care residents. Subsequently, the CPS has also been used among in-home, post-acute, and acute care populations even though CPS' clinimetric performance has not been studied in these settings. This study aimed to determine CPS agreement with the Mini Mental Status Exam (MMSE) and its predictive validity for institutionalization and death in a cohort (N=401) of elderly medical inpatients aged 75 years and over. Medical, physical and mental status were assessed upon admission. The same day, the patient's nurse completed the CPS by interview. Follow-up data were gathered from the central billing system (nursing home stay) and proxies (death). Cognitive impairment was present in 92 (23%) patients according to CPS (score >or= 2). Agreement with MMSE was moderate (kappa 0.52, P<.001). Analysis of discordant results suggested that cognitive impairment was overestimated by the CPS in dependent patients with comorbidities and depressive symptoms, and underestimated in older ones. During follow-up, subjects with abnormal CPS had increased risks of death (adjusted hazard ratio (adjHR) 1.7, 95% CI 1.0-2.8, P=.035) and institutionalization (adjHR 2.7, 95% CI 1.3-5.3, P=.006), independent of demographic, health and functional status. Interestingly, subjects with abnormal CPS were at increased risk of death only if they also had abnormal MMSE. The CPS predicted death and institutionalization during follow-up, but correlated moderately well with the MMSE. Combining CPS and MMSE provided additional predictive information, suggesting that domains other than cognition are assessed by professionals when using the CPS in elderly medical inpatients.

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AIM: Sexual orientation plays an important part in building identity during adolescence. The aim of this study was to describe patterns of sexual orientation, including sexual attraction, fantasies, affiliations and behaviour. METHODS: The study was based on the analysis of data from computerized self-administered questionnaires of a Swiss national survey on the sexual life of 16 to 20-year-old adolescents (n = 2,075 girls and 2,208 boys.). RESULTS: Overall, 95.0% of girls and 96.2% of boys described themselves as predominantly heterosexual; 1.4% of girls and 1.7% of boys as predominantly homosexual or bisexual; and 2.8% of teenagers (girls: 3.6%; boys: 2.1%) were "unsure" of their sexual orientation. The reported prevalence of homosexual attraction (girls: 2.0%; boys: 2.9%) exceeded homosexual fantasies (girls: 0.4%; boys: 0.5%) and affiliations (girls: 0.3%; boys: 0.5%). Among the 4205 respondents, 31 girls (1.5% of girls) and 56 boys (2.5% of boys) reported sexual behaviour (experience or penetrative intercourse) with a person of the same sex. Among 1.5% of girls and 2.5% of boys who reported sexual behaviour with a person of the same sex, 65% of boys and 80% of girls nevertheless considered themselves as heterosexual. CONCLUSION: For a comprehensive understanding of sexual orientation in adolescence a differentiated look at dimensions of sexual orientation is indispensable. This applies to clinical settings, public health and research.

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The purpose of this study was to explore the frequency of risk behaviours among Swiss adolescents and their links with risk perception, impulsivity and emotion regulation abilities, operationalized with the concepts of alexithymia and emo- tional openness. We recruited 144 subjects (aged 14-20), who completed the Risk Involvement and Perception Scale (RIPS-R), the UPPS Impulsive Behavior Scale, the 20-item Toronto Alexithymia Scale (TAS-20), and the 20-item Dimensions of Openness to Emotional Experiences (DOE-20) questionnaire. Findings revealed that a greater perception of benefits and a higher level of sensation seeking were associated with more involvement in risk behaviours, which are essentially socially accepted behaviours. Notably, the path model indicated that the perception of benefits was a mediator in the relationship between sensation seeking and risk behaviours. The results add to the psychological understanding of factors associated with risk behaviours in adolescence. The limitations and implications of these results for developmental theories, research, and prevention are stated.

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Cognitive impairment in schizophrenia and psychosis is ubiquitous and acknowledged as a core feature of clinical expression, pathophysiology, and prediction of functioning. However, assessment of cognitive functioning is excessively time-consuming in routine practice, and brief cognitive instruments specific to psychosis would be of value. Two screening tools have recently been created to address this issue, i.e., the Brief Cognitive Assessment Tool for Schizophrenia (B-CATS) and the Screen for Cognitive Impairment in Psychiatry (SCIP). The aim of this research was to examine the comparative validity of these two brief instruments in relation to a global cognitive score. 161 patients with psychosis (96 patients diagnosed with schizophrenia and 65 patients diagnosed with bipolar disorder) and 76 healthy control subjects were tested with both instruments to examine their concurrent validity relative to a more comprehensive neuropsychological assessment battery. Scores from the B-CATS and the SCIP were highly correlated in the three diagnostic groups, and both scales showed good to excellent concurrent validity relative to a Global Cognitive Composite Score (GCCS) derived from the more comprehensive examination. The SCIP-S showed better predictive value of global cognitive impairment than the B-CATS. Partial and semi-partial correlations showed slightly higher percentages of both shared and unique variance between the SCIP-S and the GCCS than between the B-CATS and the GCCS. Brief instruments for assessing cognition in schizophrenia and bipolar disorders, such as the SCIP-S and B-CATS, seem to be reliable and promising tools for use in routine clinical practice.

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Adolescence is an important time for acquiring high peak bone mass. Physical activity is known to be beneficial to bone development. The effect of estrogen-progestin contraceptives (EPC) is still controversial. Altogether 142 (52 gymnasts, 46 runners, and 42 controls) adolescent women participated in this study, which is based on two 7-year (n =142), one 6-year (n =140) and one 4-year (n =122) follow-ups. Information on physical activity, menstrual history, sexual maturation, nutrition, living habits and health status was obtained through questionnaires and interviews. The bone mineral density (BMD) and content (BMC) of lumbar spine (LS) and femoral neck (FN) were measured by dual- energy X-ray absoptiometry. Calcaneal sonographic measurements were also made. The physical activity of the athletes participating in this study decreased after 3-year follow-up. High-impact exercise was beneficial to bones. LS and FN BMC was higher in gymnasts than in controls during the follow-up. Reduction in physical activity had negative effects on bone mass. LS and FN BMC increased less in the group having reduced their physical activity more than 50%, compared with those continuing at the previous level (1.69 g, p=0.021; 0.14 g, p=0.015, respectively). The amount of physical activity was the only significant parameter accounting for the calcaneal sonography measurements at 6-year follow-up (11.3%) and reduced activity level was associated with lower sonographic values. Long-term low-dose EPC use seemed to prevent normal bone mass acquisition. There was a significant trend towards a smaller increase in LS and FN BMC among long-term EPC users. In conclusion, this study confirms that high-impact exercise is beneficial to bones and that the benefits are partly maintained even after a clear reduction in training level at least for 4 years. Continued exercise is needed to retain all acquired benefits. The bone mass gained and maintained can possibly be maximized in adolescence by implementing high-impact exercise for youngsters. The peak bone mass of the young women participating in the study may be reached before the age of 20. Use of low-dose EPCs seems to suppress normal bone mass acquisition.

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As the title of the special issue indicates, controversy surrounds augmentation of brain cognition in humans. Lacking efficacious drugs for Alzheimer's disease (AD) and with many AD patients recruited for clinical trials that unfortunately do not provide the expected results, one wonders whether to test cognition enhancement strategies in individuals without symptoms of cognition decline. This opinion article presents the view that safe drugs and or dietary supplements should be tested worldwide in aged individuals under the control of a non-for-profit organization.

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This doctoral dissertation explores the intra-organizational dynamics of a strategic renewal process. The main research question is how the pursuit of change and organizational inertia co-exist, intertwine, and collide in organizational cognition and capabilities during the strategic renewal. It is a comprehensive study on how organizational capabilities, organizational cognition, and structure enhance and inhibit change. Theoretically, the study is positioned in the modern tradition of strategy research, using the dynamic capability view and the organizational and managerial cognition research tradition as the main theoretical frames. Empirically, the study is a longitudinal case study of the Finnish Broadcasting Company (Yle), following the organizational changes during the years of 2011-1014. The analysis is based on both quantitative and qualitative data, which was collected during the research process using surveys, interviews, and archives. The main theoretical contribution is the application of the two theoretical approaches in one study. Empirically, the study contributes to operationalization of the concepts related to the dynamic capability view and organizational cognition, in a media context that is going through drastic changes due to digitalization. Furthermore, the case of a public broadcasting company extends the application of the theoretical concepts to the context of public management. The results suggest that renewal is a complex process, in which an organization’s perceptions intertwine with the strategic actions and decision-making. The change evolves pathdependently: the past experiences, routines, and organizational structures tend to dictate the future visions, desires, and actions. The study also reveals how the public nature of an organization adds to the tensions between change and organizational inertia, and hampers the decision-making. The doctoral dissertation consists of six research papers, each of which explores the phenomenon under study from a different perspective.

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Self-presentation has been identified as playing a key role in the perfonnance of various potentially hazardous health behaviours such as substance abuse, eating disorders and reckless behaviours (Leary, Tchividjian, & Kraxberger, 1994; Martin & Leary, 2001; Martin, Leary, & O'Brien, 2001). The present study investigated the role of selfpresentation on adolescent health-risk behaviours. Specifically, this study examined the prevalence of adolescent identified health-risk behaviours rooted in self-presentational motives in youths aged 13-18 years. The current study also identified the specific images associated with these behaviours desired by youth, and the targets of these behaviours. Also, the relationship between these behaviours, and several trait measures (social physique anxiety, public-self consciousness, fear of negative evaluations, selfpresentational efficacy) of self-presentation were examined. Finally, the gender differences in health risk behaviours and self-presentational concerns were examined. Participants in the present study were 96 adolescent students, 34 male and 62 female, recruited from various private schools across Southern Ontario. Students ranged in age from 13 to 18 years for both males (M age = 15.81 years, SD = 1.49) and females (M age = 14.89 years, SD = 1.17) and ranged from grades 8 through 13. Results of the current study suggested that Canadian adolescents between the ages of 13 and 18 years participated in health risk behaviours for self-presentational purposes. Drinking alcohol, skipping school, and performing stunts and dares were identified as the most common health risk behaviours performed for self-presentational purposes by both males and females. Appearing fun and cool were the most commonly reported desired images while appearing brave and mature were the least reported. The most desired target group cited was same sex friends, followed by other sex friends. Trait measures of self-presentational concerns identified females as being higher in public self-consciousness, and social physique anxiety than males. Males were found to be higher in self-presentational efficacy than females. The total number of health risk behaviours was predicted by selfpresentational efficacy and social physique anxiety for males, and social physique anxiety for females. Findings of the current study suggest that Canadian adolescents' health risk behaviours are rooted, in part, in self-presentational motives. Thus far, an educational approach to health interventions has been favoured and/or adopted by teachers, health promoters, and educators (Jessor, 1992). Implications of the current study suggest that although educational interventions are beneficial in presenting the associated risks with certain activities and/or behaviours, one reason this type of approach may be ineffective in changing adolescent behaviour over the long run is that it does not address the strong and prominent influences of interpersonal motives on health damaging behaviour. It is evident that social acceptance and public image are of importance to adolescents, and the desire to make the "right" impression and to achieve peer approval and acceptance often override health and safety concerns (Jessor, 1992). Thus, a self-presentational approach focusing on changing the images associated with the behaviours may be more successful at deterring adolescent health risk behaviours.

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This thesis investigated the question, "What nourishes the adolescent spirit in the classroom?" Action research was conducted by the teacher of 16 grade 8 participants. By undergoing Kessler's (2000) "Passages Program," the students participated in 6 sessions which exposed them to a holistic intrapersonal curriculum. Student journal responses were documented after each session. The action researcher also kept journal reflections after each session. Upon completion of the 6 sessions, a postinterview was conducted which posed the research question. The research found that the adolescent spirit gets nourished through encouragement by the teacher, peers, and parents. This increases their competency, which increases their confidence, and ultimately their self-esteem goes up, which affects their selfconcept. In addition, the role of the teacher permeates every aspect of what nourishes the adolescent spirit in the classroom. In addition to the encouragement of the student, how a teacher teaches plays a vital role. A holistic approach to teaching provided the best atmosphere for the adolescent. It promoted creativity and choice, which stimulated the spirit of the adolescent. By working from a holistic philosophy, the teacher/action researcher created an environment conducive to teaching the whole person, which ultimately nourished the participants' spirit. The research highlighted that in order for this type of environment to exist the teacher needs to make a conscious and deliberate effort to look within and develop their inner self before they can begin to promote this type of classroom for the adolescents they teach. When teachers and students develop an inner life together, they can begin to work in harmony to achieve an atmosphere where the teaching and learning environment becomes one seamless transaction. Only then can one's whole potential be realized.

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Beliefs about the rightness or wrongness of engaging in various antisocial acts, referred to here as nonnative beliefs legitimizing antisocial behaviour (nblab), have been shown to playa role in the emergence oflater antisocial behaviour. The current study represented an attempt to understand whether parental monitoring and parent-child attachment have differential relationships with these antisocial nonnative beliefs in adolescents of different temperaments. The participants, 7135 adolescents in 25 high schools (ages 10- 18 years, M = 15.7) completed a wide-ranging questionnaire as part of the broad Youth Lifestyle Choices - Community University Research Alliance project, whose goal is to identify and describe the major developmental pathways of risk behaviours and resilience in youth. Two aspects of monitoring (monitoring knowledge and surveillance/tracking), attachment security, and two measures of temperament (activity level and approach) were examined for main effects and in interactions as predictors of adolescent nonnative beliefs. All of these measures were based on adolescent self-ratings on either 3- or 4-point Likert-type scales. Several important results emerged from the study. Males were higher than females in nblab; parental monitoring knowledge and adolescent attachment security were negatively related to nblab; and temperamental activity level was positively related. Monitoring knowledge, the strongest of the predictors, was much more strongly related to nonnative beliefs than was parental surveillance/tracking, supporting the contention that it is how much parents actually know, and not their surveillance efforts, that predict adolescent nonnative beliefs. A surprising finding that is of the utmost importance was that, although several of the interactions tested were significant, none were considered to be of a meaningful magnitude (defined as sr^ > .01). The current study supported the suggestion that normative beliefs legitimizing antisocial behaviour are multiply determined, and the results were discussed with respect to the observed differential relations of parental monitoring, parent-child attachment, temperament, age, and gender to antisocial normative beliefs in adolescents. Also discussed were the need to test other parenting, temperament, and other variables that may be involved in the development of nblab; the need to directly test possible mechanisms explaining the links among the variables; and the usefulness of longitudinal research in determining possible directions of causality and developmental changes in the relationships.

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This study examined factors contributing to the differences in left ventricular mass as measured by Doppler echocardiography in children. Fourteen boys (10.3 ± 0.3 years of age) and 1 1 girls (10.5 ± 0.4 years of age) participated in the study. Height and weight were measured, and relative body fat was determined from the measurement of skinfold thickness according to Slaughter et al. (1988). Lean Body Mass was then calculated by subtracting the fat mass from the total body mass. Sexual maturation was self-assessed using the stages of sexual maturation by Tanner (1962). Both pubic hair development and genital (penis or breast for boys and girls respectively) development were used to determine sexual maturation. Carotid Pulse pressure was assessed by applanation tomometry in the left carotid artery. Cardiac mass was measured by Doppler Echocardiography. Images of cardiac structures were taken using B-Mode and were then translated to M- Mode. The dimensions at the end diastole were obtained at the onset of the QRS complex of the electrocardiogram in a plane through a standard position. Measurements included: (a) the diameter of the left ventricle at the end diastole was measured from the septum edge to the endocardium mean border, (b) the posterior wall was measured as the distance from to anterior wall to the epicardium surface, and (c) the interventricular septum was quantified as the distance from the surface of the left ventricle border to the right ventricle septum surface. Systolic time measurements were taken at the peak of the T-wave of the electrocardiogram. Each measurement was taken three to five times before averaging. Average values were used to calculate cardiac mass using the following equation (Deveraux et al. 1986). Weekly physical activity metabolic equivalent was calculated using a standardize activity questionnaire (Godin and Shepard, 1985) and peakV02 was measured on a cycloergometer. There were no significant differences in cardiovascular mesurements between boys and girls. Left ventricular mass was correlated (p<0.05) with size, maturation, peakV02 and physical activity metabolic equivalent. In boys, lean body mass alone explained 36% of the variance in left ventricular mass while weight was the single strongest predictor of left ventricular mass (R =0.80) in girls. Lean body mass, genital developemnt and physical activity metabolic equivalent together explained 46% and 81% in boys and girls, respectively. However, the combination of lean body mass, genital development and peakV02 (ml kgLBM^ min"') explained up to 84% of the variance in left ventricular mass in girls, but added nothing in boys. It is concluded that left ventricular mass was not statistically different between pre-adolescent boys and girls suggesting that hormonal, and therefore, body size changes in adolescence have a main effect on cardiac development and its final outcome. Although body size parameters were the strongest correlates of left ventricular mass in this pre-adolescent group of children, to our knowledge, this is the first study to report that sexual maturation, as well as physical activity and fitness, are also strong associated with left ventricular mass in pre-adolescents, especially young females. Arterial variables, such as systolic blood pressure and carotid pulse pressure, are not strong determinants of left ventricular mass in this pre-adolescent group. In general, these data suggest that although there is no gender differences in the absolute values of left ventricular mass, as children grow, the factors that determine cardiac mass differ between the genders, even in the same pre-adolescent age.