Executive functions in school-aged children exposed to airborne manganese: A multilevel analysis.

Neuropsychological alterations have been identified in populations heavily exposed to metals with neurotoxic potential, such as manganese (Mn). This study examined the associations between Mn environmental exposure in school-aged children and executive functions, using structural equation modeling. Children, aged between 7 and 12 years (N = 181), were recruited from four elementary schools located in a region that is under the influence of atmospheric emissions from a ferro-manganese alloy plant in the municipality of Simões Filho, Bahia, Brazil. The following cognitive functions were evaluated: Intelligence, Inhibitory Control, Cognitive Flexibility, Verbal and Design Fluency, Verbal and Visual Working Memory and Attention. We performed structural equation modeling to identify the following executive functions latent variables: working memory, inhibitory control and cognitive flexibility. We further analyzed the relations between executive functions and Mn measured in hair (MnH) and toenails (MnTn) with linear mixed models, after controlling for co-variables. A positive effect at the individual level on working memory, inhibition control and cognitive flexibility was observed with MnTn after controlling for co-variables, but no association was found with MnH levels. However, children attending school most environmentally exposed to Mn emissions, which had the highest rate of Mn dust deposition, had the poorest scores on working memory. These findings suggest both benefits and risk of Mn on children's cognitive development.

Neuropsychological effects of direct-acting antiviral treatment for Hepatitis C virus subjects: A systematic review.

Direct-acting antivirals (DAAs) have been approved in recent years to treat patients infected by the Hepatitis C virus (HCV). The DAAs treatment is well tolerated and increases sustained virological responses, but there is no consensus about the neuropsychological functioning related to the treatment. This systematic review aims to provide an overview of the recent findings exploring the cognitive effects of DAAs treatment in patients with HCV. After a systematic search on PubMed, Embase, Scopus and LILACS, studies that assessed neuropsychological data related to DAAs treatment were included. We found nine articles, considering the inclusion and exclusion criteria. Three other manuscripts were included after searching for the references listed in the previously mentioned articles. We observed methodological heterogeneity in terms of neuropsychological tests used, cognitive domain explored and the sample characteristic presented between the studies. Studies presented data from HCV subjects monoinfected with or without cirrhosis, advanced liver disease and post-transplant patients; and HCV subjects coinfected with human immunodeficiency virus (HIV). Most results from the 12 studies that explored the effect of DAAs treatment in HCV subjects' neurocognitive functioning demonstrated cognitive improvement following treatment. In general, HCV and HCV/HIV subjects improved processing speed, verbal fluency and verbal/visual episodic memory. The DAAs treatment is effective for neurocognitive functioning in HCV monoinfected and coinfected subjects, with or without advanced liver disease, since neuropsychological scores increased after treatment. Further studies, however, are needed to confirm these findings.

Neurocognitive Impairment in Bipolar Disorder and Associated Factors: Using Population-based Norms and a Strict Criterion for Impairment Definition.

BACKGROUND: Cognitive impairment is often identified in individuals with bipolar disorder and is associated with their functional impairment. However, there is controversy surrounding potential classification methods for impairment in cognitive measures. OBJECTIVE: To examine the proportion of cognitive measures indicating impairment of attention, processing speed, memory, visuoconstructional abilities, and executive functions in individuals with bipolar disorder type I (euthymic) and healthy controls, using a strict criterion for defining impairment. METHODS: We gave 43 individuals with bipolar disorder type I and 17 healthy controls a comprehensive clinical and neuropsychological assessment. All scores were standardized using means and standard deviations according to age. Impaired performance in all cognitive measures was determined using a distribution-based threshold of z=±1645. The effects of the sociodemographic and clinical variables on cognitive performance were examined using multiple stepwise backward regression analyses. RESULTS: Clinically significant cognitive impairment was observed more frequently in the bipolar disorder group, compared to controls, on all measures. From participant factors, we found that level of education and number of manic episodes predicted variation in more cognitive measure scores. DISCUSSION: The use of population-based norms to standardize cognitive measures, and a strict criterion to define cognitive impairment, in individuals with bipolar disorder type 1 and healthy controls resulted in a prevalence of impairment in cognitive domains' frequencies of deficits that fell within the ranges previously reported in meta-analyses. CONCLUSIONS: Clinically introducing population norms and a stringent cognitive impairment criterion can facilitate more accurate measures of cognitive impairment in individuals with bipolar disorder.

Subjective Well-Being of Adolescents in Luxembourg, Germany, and Brazil During the COVID-19 Pandemic.

PURPOSE: This study explores adolescent well-being during the first wave of the COVID-19 pandemic in two high-income countries from Europe and one middle-income country from South America. The aim is to investigate the correlates of different dimensions of subjective well-being in 10- to 16-year-olds from different cultural contexts. METHODS: An online, self-report questionnaire was completed by 1,613 adolescents in Luxembourg, Germany, and Brazil between May and July 2020. The outcome variables were measures of life satisfaction and emotional well-being during the COVID-19 pandemic. The study included a range of sociodemographic, interpersonal, and intrapersonal covariates. Data were analyzed using descriptive statistics and latent variable structural equational modeling. RESULTS: A two-factor model of subjective well-being, consisting of life satisfaction and emotional well-being latent constructs, fitted well with this sample data for Luxembourg, Germany, and Brazil. Results showed that gender, socioeconomic status, intrapersonal factors, quantity and type of schoolwork, and relationships with adults were important common predictors of individual differences in subjective well-being during COVID-19. Fear of illness emerged as the strongest correlate of emotional well-being across the three countries. CONCLUSIONS: This study indicates that girls and adolescents from low-income homes may be especially vulnerable to negative secondary impacts of COVID-19 that can affect mental health. It identified several common correlates of subjective well-being in adolescents from different cultural settings, including factors that may be changeable, such as the following: the way adults listen to adolescents, schoolwork during distant learning, and fear of illness. Findings can inform the development of quality interventions for promoting the well-being of adolescents during a global pandemic.

Neurocognitive aspects of ketamine and esketamine on subjects with treatment-resistant depression: A comparative, randomized and double-blind study.

The objective of this study is to evaluate cognition in patients using either ketamine or esketamine to treat TRD. We also evaluate if both ketamine and esketamine as one group influence cognition in patients with TRD. Fifty-four patients with TRD were infused with either ketamine or esketamine and were assessed at three time points: baseline, 24 h, and 7 days after infusion. We applied neuropsychological tests to evaluate executive functions, processing speed, short term memory, and auditory-verbal episodic memory. There is no cognitive difference between ketamine and esketamine, with the exception of one variable. When considered as one group, ketamine and esketamine do not impair cognition; on the contrary, they improve some neuropsychological functions such as visuospatial short-term memory, executive functions, processing speed, and several measures related to episodic verbal memory. Ketamine and esketamine do not present differing cognitive effects when used in antidepressant doses to treat TRD. Furthermore, they rapidly improve many cognitive aspects of patients with TRD at 24 h after the infusion and maintain these effects for at least 7 days.

Neuropsychological Effects of Mercury Exposure in Children and Adolescents of the Amazon Region, Brazil.

BACKGROUND: Studies with children exposed to methylmercury (MeHg) through fish consumption in the Brazilian Amazon region report that the high levels of hair Hg are associated with significant decreases in intelligence, memory, attention, and visuospatial processing. OBJECTIVE: To investigate the relationship between mercury exposure and neuropsychological functions in riverside communities of the Brazilian Amazon. METHOD: 263 participants aged 6 to 14 years old were assessed, from resettlement regions, near the Madeira river, Rondônia, Brazil. To assess the neuropsychological functions we used the following instruments: intelligence (WASI), working memory (Corsi Block-Tapping Task and Digit Span), verbal fluency (Word Generation - NEPSY II), inhibitory control (Inhibition Errors - NEPSY II), shifting (Trail Making Test) and manual motor dexterity (Grooved PegBoard Test). Socioeconomic status was obtained through household surveys. Total Hg levels were quantified hair samples (Total HgH) collected from the occipital region of the scalp and analyzed by Cold Vapor Atomic Absorption Spectrometry. RESULTS: The group in the upper quartile of Total HgH levels presented lower scores on the tasks that assessed estimated IQ, visuospatial working memory, semantic knowledge and phonological verbal fluency, when compared to the group in the lower quartile level. A regression analysis controlled for age, sex, and maternal education showed that for each increase of 10 µg/g of Total HgH, there was a decrease around half standard deviation in Verbal IQ, estimated IQ scores, semantic knowledge, phonological verbal fluency and for verbal and visuospatial working memory. CONCLUSIONS: High concentrations of Total Hg in hair were associated with a lower performance in neuropsychological functions tests. The results show that environmental exposure to Hg is associated to children and adolescents' lower neuropsychological performance in the riverine and resettled areas of the Brazilian Amazon region.

A neuropsychological study comparing patients infected with HCV and HBV without psychiatric comorbidities.

Hepatitis C is one of the most common chronic infectious diseases worldwide, with well-documented extra-hepatic manifestations, such as a broad number of cognitive deficits. These impairments may be explained by psychiatric comorbidities, which have not been investigated properly in the literature. In order to elucidate a specific hepatitis C virus (HCV) induced cognitive impairment not related to mental disorders, neuropsychological performance of patients infected with HCV was compared with that of patients infected with hepatitis B virus cognitive impairment, especially psychiatric comorbidities. A total of 33 patients infected with HCV and 22 patients infected with HBV were included in the study. There were no significant differences between the two groups with regard to age or years of education. The group of patients infected with HCV performed significantly worse on visuo-spatial memory tasks after adjusting for years of education and age. There were no significant differences between patients infected with HCV and patients infected with HBV with regards to other neuropsychological functions. The data indicate that patients infected with HCV patients have poorer visuo-spatial memory performance than patients infected with HBV, suggesting that the cognitive deficit may be specific to HCV infection and not to secondary comorbid psychiatric disorders.

[Cognitive-behavioral therapy for depression]. / Terapia cognitivo-comportamental da depressão.

OBJECTIVE: To describe the use of cognitive techniques and to review studies on the efficacy of CBT in the treatment of depression. METHOD: A non-systematic review of the literature of original studies complemented with data from meta-analyses and specialized textbooks. RESULTS: The fundamentals of cognitive-behavioral therapy in the treatment of depression are described and the evidence of short- and long-term efficacy is reviewed. The use of pharmacological therapy in conjunction with CBT is also discussed. CONCLUSIONS: CBT in the treatment of depression is one of the therapeutic modalities with the highest empirical evidence of efficacy, whether applied alone or in combination with pharmacotherapy.

Escala de Percepção de Risco sobre Covid-19/Isolamento Social: Propriedades Psicométricas / Escala de Percepción de Riesgo sobre Covid-19 y Aislamiento Social: Propiedades Psicométricas / Psychometric Properties of Risk Perception Scale about Covid-19 and Social Isolation (RPSCI)

Risk perception is a concept related to the decision-making process and allows people to perceive the hazards surrounding the context and choose the best preventive methods to avoid them. The COVID-19 pandemic was a remarkable era in which people had to adopt protective methods, such as social isolation, to reduce the possibility of being contaminated by the virus. This study covers the development, psychometric properties, and norms of a scale to assess Risk Perception regarding COVID-19 and Social Isolation. The analysis suggested good expert agreement regarding the adequacy of the scale content and items and factor analysis suggested two factors, called the emotional and cognitive domains. The composite reliability suggested the internal consistency of the scale and its factors. All the results of this study suggest that this scale presents evidence of construct validity, constituting a reliable instrument. This new instrument may be used to evaluate risk perception related to COVID-19 and Social Isolation.

La percepción del riesgo es un concepto relacionado con el proceso de toma de decisiones y permite a las personas percibir los peligros en el contexto y elegir los mejores métodos de prevención para evitarlos. La pandemia de COVID-19 es una era notable en la que las personas deben adoptar métodos, como el aislamiento social, para reducir la posibilidad de ser contaminados por el virus. Este estudio proporciona el desarrollo, las propiedades psicométricas y las normas de una escala para evaluar Percepción de Riesgo sobre el COVID-19 y el Aislamiento Social. El análisis sugirió un buen acuerdo de expertos sobre el ajuste del contenido y la escala de ítems y el análisis factorial apuntó dos factores denominados dominios emocional y cognitivo. La confiabilidad compuesta sugirió consistencia interna de la escala y sus factores. Todos los resultados de este estudio proponen que esta escala presenta evidencia de validez de constructo y es un instrumento confiable. Este nuevo instrumento podrá ser utilizado para evaluar la percepción de riesgo sobre el COVID-19 y el aislamiento social.

A percepção de risco é um conceito relacionado ao processo de tomada de decisão e permite que as pessoas percebam os perigos em torno do contexto e escolham os melhores métodos de prevenção para evitá-los. A pandemia do COVID-19 é uma era marcante em que as pessoas devem adotar métodos de proteção, como o isolamento social, para reduzir a possibilidade de serem contaminados pelo vírus. Este estudo fornece o desenvolvimento, as propriedades psicométricas e normas de uma escala para avaliar Percepção de Risco sobre COVID-19 e Isolamento Social. A análise sugeriu boa concordância dos especialistas sobre o ajuste de conteúdo e itens da escala, e a análise fatorial sugeriu dois fatores denominados domínios emocionais e cognitivos. A confiabilidade composta sugeriu a consistência interna da escala e seus fatores. Todos os resultados deste estudo sugerem que esta escala apresenta evidências de validade de construto, sendo um instrumento confiável. Este novo instrumento poderá ser utilizado para avaliar a percepção de risco sobre a COVID-19 e o Isolamento Social.

Environmental manganese exposure and associations with memory, executive functions, and hyperactivity in Brazilian children.

Manganese (Mn) is an essential element, however high levels of Mn have been associated with lower neuropsychological performance and behavioral problems in children. We investigated the associations between hair Mn concentrations and neuropsychological and behavioral performances among children with long-term exposure to airborne Mn aged between 7 and 12 years. Neuropsychological performance included tests of: verbal memory, inhibitory control, cognitive flexibility, verbal fluency, and motor function. We used the Conners Abbreviated Rating Scale for teachers to assess students' behaviors of hyperactivity. Hair manganese (MnH) concentrations in children and exposure to airborne manganese from a ferro-manganese alloy plant were analyzed and correlated with tests scores. Multivariable linear models adjusting for potential confounders showed that elevated levels of MnH were associated with lower performance in verbal memory, as measured by the free recall after interference (ß = - 1.8; 95% CI: - 3.4, - 0.2), which indicates susceptibility to interference, and Delayed Effect (ß = -2.0; 95% CI: -3.7, - 0.2), representing a loss of information over time. Additionally, we found patterns of effect modification by sex in three subtests measuring verbal memory: the free recall after interference score, Interference Effect, and Delayed Effect (all at p < 0.10). Overall, the results suggest that long-term airborne Mn exposure may be associated with lower performance in verbal memory, and hyperactivity behaviors.

Environmental Co-Exposure to Lead and Manganese and Intellectual Deficit in School-Aged Children.

Studies have demonstrated that, for urban children, dust represents the main exposure to sources of metals like lead (Pb) and manganese (Mn). We aimed to investigate the exposure to these metals and their association with intellectual deficit in children living in an industrial region. This cross-sectional study recruited volunteers from four elementary schools in the town of Simões Filho, Brazil. We evaluated 225 school-aged children (7⁻12 years) for blood lead (PbB) and manganese hair (MnH) and toenails (MnTn) by graphite furnace atomic absorption spectrometry. Child and maternal IQs were estimated using the Wechsler Abbreviated Scale for Intelligence (WASI). Median and range PbB were 1.2 (0.3⁻15.6) µg/dL. MnH and MnTn medians (ranges) were 0.74 (0.16⁻8.79) µg/g and 0.85 (0.15⁻13.30) µg/g, respectively. After adjusting for maternal IQ, age and Mn exposure, child IQ drops by 8.6 points for a 10-fold increase in PbB levels. Moreover, an effect modification of Mn co-exposure was observed. In children with low MnTn, association between Pb and child IQ was not significant (ß = -6.780, p = 0.172). However, in those with high MnTn, the association was increased by 27.9% (ß = -8.70, p = 0.036). Low Pb exposure is associated with intellectual deficit in children, especially in those with high MnTn.

Validity evidence for the Neuropsychological Test for the Assessment of Visuospatial Binding: a working memory test / Evidências de validade do Teste Neuropsicológico para Avaliação do Binding Visuoespacial: um teste de memória operacional / Evidencias de validez del Test Neuropsicológico para la Evaluación de Binding Visuoespacial: un test de memoria operativa

The Neuropsychological Test for the Assessment of Visuospatial Binding (TNABV) was developed to measure the Working Memory binding for object-location features. This study aimed to provide validity evidence related to the content and internal structure of the TNABV. To investigate the evidence based on internal structure, the sample was composed of 1173 people. Participants were between 18 and 95 years of age. In order to investigate the content-related validity evidence, a judgment was performed through the analysis of seven experts. The data analysis was carried out through exploratory factor analysis, the Internal Consistency Content Validity Index (CVI). The result suggested a one-dimensional model with an explained variation of 41.78% and Cronbach's alpha of .82. The total CVI showed an agreement of .98. The findings indicated that the psychometric properties evaluated in the TNABV are adequate.(AU)

O Teste Neuropsicológico para Avaliação do Binding Visuoespacial (TNABV) foi desenvolvido para avaliar o binding da memória operacional para os recursos de objeto-localização. Este estudo investigou as evidências de validade relacionadas ao conteúdo e estrutura interna do TNABV. Para realizar as evidências baseadas na estrutura interna, a amostra foi composta por 1173 pessoas. Os participantes tinham entre 18 e 95 anos. Para investigar a validade das evidências baseadas no conteúdo, foi realizado um julgamento pela análise de sete especialistas. A análise dos dados foi realizada por meio de análise fatorial exploratória, Índice de Confiabilidade e Validade de Conteúdo (IVC). O resultado sugeriu um modelo unidimensional com uma variação explicada de 41,78% e o alfa de Cronbach de 0,82. O IVC total mostrou uma concordância de 0,98. Os achados indicaram que as propriedades psicométricas avaliadas no TNABV são adequadas.(AU)

El Test Neuropsicológico para la Evaluación de Binding Visuoespacial (TNABV) se desarrolló para evaluar el binding de la memoria operativa para los recursos de objeto-localización. Este estudio investigó las evidencias de validez relacionadas con el contenido y la estructura interna del TNABV. Para explorar las evidencias basadas en la estructura interna, la muestra se compuso por 1173 personas. Los participantes tenían entre 18 y 95 años. Para investigar la validez de las evidencias basadas en el contenido se realizó un juicio mediante la revisión de siete expertos. El análisis de los datos se ejecutó utilizando el análisis factorial exploratorio, el Índice de Confiabilidad y la Validez de Contenido (CVI). El resultado sugirió un modelo unidimensional con una variación explicada del 41,78% y un alfa de Cronbach de 0.82. El CVI total mostró una concordancia de 0,98. Los hallazgos indicaron que las propiedades psicométricas evaluadas en el TNABV son adecuadas.(AU)

Evidence of validity of the Attentional Performance Test (APT) / Evidências de validade do teste do desempenho atencional (TDA) / Evidencia de validez del test de desempeño atencional

This study aims to present evidence of validity of the Attentional Performance Test (APT). The search for evidence based on content, internal structure and reliability was carried out. The content's evidence was run with the expert judgement (n = 07; k = 0.84) and semantic analysis (n = 12, k = 0.77). Their results suggested an adequate agreement with the content of the assessment of sustained attention (S.A), verbal commands and the images of the instrument. An analysis of the factorial structure (n = 1086) resulted on 2 main factors, 4 dimensions and 12 measures (RMSR = 0.08). An analysis of internal consistency (n = 1086) of the APT showed adequate values (α > 70). This study indicated that the APT presents evidence for content, construct and reliability. The present results contribute to APT evidences to confirm it as an adequate psychometric instrument to assess attention.

Este estudo tem por objetivo apresentar evidências de validade do Teste do Desempenho Atencional (TDA). Buscaram-se evidências baseadas no conteúdo, na estrutura interna e na fidedignidade. As evidências de conteúdo foram realizadas por intermédio da análise de juízes (n = 7; k = 0,84) e análise semântica (n = 12, k = 0,77), cujos resultados sugeriram concordância adequada quanto ao conteúdo de avaliação da atenção sustentada, aos comandos verbais e às imagens utilizadas no instrumento. A análise da estrutura fatorial (n = 1.086) do instrumento resultou em dois fatores principais, quatro dimensões e 12 medidas (RMSR = 0,08). A análise da consistência interna (n = 1.086) do TDA apresentou valores adequados (α > 70). Em conjunto, os resultados deste estudo mostram que o TDA apresenta evidências suficientes para o conteúdo, o construto e a fidedignidade. Os atuais resultados contribuem para confirmar o TDA como instrumento psicométrico adequado para avaliação da atenção.

Este estudio tiene como objetivo presentar evidencia de validez para el Test de Desempeño Atencional (TDA). Se realizó la búsqueda de evidencia basada en contenido, estructura interna y fiabilidad. Las evidencias de contenido se realizaron a través del análisis de expertos (n = 7; k = 0,84) y análisis semántico (n = 12, k = 0,77) y sus resultados sugirieron una adecuada concordancia con el contenido de evaluación de la atención sostenida, los comandos verbales y las figuras del instrumento. El análisis de la estructura factorial (n = 1.086) del instrumento se manifestó por dos factores principales, cuatro dimensiones y 12 medidas (RMSR = 0,08). El análisis de consistencia interna (n = 1.086) del TDA arrojó valores adecuados (α > 70). Este estudio sugiere que el TDA presenta evidencia suficiente de contenido, constructo y fiabilidad. Los resultados confirman que el TDA es un instrumento psicométrico adecuado para evaluación de la atención.

Normative data of the Barratt Impulsiveness Scale 11 (BIS-11) for Brazilian adults.

OBJECTIVE: The Barratt Impulsiveness Scale (BIS-11) is a valid and reliable instrument, and one of the most often used tools to assess impulsivity. This study assesses the performance of a large sample of adults by using a version of BIS-11 adapted to Brazilian Portuguese. METHODS: We assessed 3,053 adults from eight Brazilian states. Internal consistencies and performance data were presented for two correction criteria of BIS-11: original and the two-factor score. RESULTS: The associations between age, sex, region, and education and the BIS-11 scores present very small effect sizes. Therefore, we provided a percentile rank parameter for the different BIS-11 subscores considering the whole sample. Given the internal consistency of the two correction systems, we found that only the two-factor system fulfills the psychometric criteria of Cronbach's alpha (cutoff value of at least 0.6). CONCLUSION: Our results support the use of the Brazilian adaptation of BIS-11 in different regions of the country as a measure of impulsivity. Since high impulsiveness is a characteristic of several dysfunctional behaviors, the establishment of normative parameters is of utmost relevance and should be extended to other age ranges and populations in future studies.

Working memory screening, school context, and socioeconomic status: an analysis of the effectiveness of the working memory rating scale in Brazil.

OBJECTIVE: The study explores the psychometric properties of the Brazilian-Portuguese version of the Working Memory Rating Scale (WMRS-Br) in a population of 355 young children from diverse socioeconomic status and schooling backgrounds. METHOD: Public and private school teachers completed the WMRS-Br and children were assessed on a range of objective cognitive measures of fluid intelligence, working memory, and attention. RESULTS: Reliability and validity of the WMRS-Br were excellent across the public and private school sample. The WMRS-Br manifested substantial links with objective measures of working memory and medium links with selective attention, switching, and interference suppression. Confirmatory factor analyses suggest that a shorter version of the scale provides an adequate fit to the data. CONCLUSION: The WMRS-Br represents a valid screening tool in a Latin American context that has the potential to improve the early detection of working memory deficits in children growing up in poverty.

Elevated airborne manganese and low executive function in school-aged children in Brazil.

Exposure to airborne manganese (Mn) has been associated with neurotoxic effects, including motor and cognitive deficits. The main deficits related to excessive exposure to Mn are predominantly the dysfunction of fronto-striatal and dopaminergic circuits observed in animal experimental studies, which are involved in attention, working memory and motor function. The present study aims to assess the association between elevated Mn exposure and performance on executive function and attention neuropsychological tests in children living in two communities near a ferro-manganese alloy plant. Seventy children aged between 7 and 12 years with no history of neurologic disease and an estimated IQ >68 (Vocabulary and Block Design subtests) that had lived near the iron-Mn production alloy plant for at least 1.5 years were included. Participants were assessed for cognitive functioning with neuropsychological measures for sustained attention (Test of Visual Attention - TAVIS-3R), cognitive flexibility (WCST), and verbal and visual working memory (WISC-III Digit Span subtest and Corsi Block). Manganese hair (MnH) levels were used as a biomarker of exposure. Mean scores among study participants were lower than general population norms/averages for block design, digit span, reaction time and commission errors. The median MnH level was 11.48 (range 0.52-55.74) µg/g, and no difference between sexes was observed. Spearman's correlation analysis showed a significant inverse correlation between MnH levels and estimated IQ (rho=-0.448, p=0.0001), Vocabulary (rho=-0.272, p=0.02), Block Design (rho=-0.485, p=0.00002) and Digit Span (rho=-0.410, p=0.0004). Multiple regression analyses detected inverse associations between log MnH and scores on estimated IQ (ß=-9.67; 95%CI=-16.97 to -2.37), Block Design (ß=-2.50; 95%CI=-3.91 to -1.10) and Digit Span Total (ß=-2.59; 95%CI=-4.13 to -1.05) standardized scores and the number of correct answers in forward and backward Digit Span methods, after adjusting for covariates (ß=-1.32=95%CI=-2.23 to -0.40; ß=-1.09 95%CI=-2.02 to -0.16, respectively). The results suggest that airborne Mn exposure may be associated with lower IQ and neuropsychological performance in tests of executive function of inhibition responses, strategic visual formation and verbal working memory. Executive function is dependent on the fronto-striatal circuit, which may be disrupted by Mn accumulation in the brain.

Elevated manganese exposure and school-aged children's behavior: a gender-stratified analysis.

High levels of waterborne manganese have been associated with problematic behavior in school-aged children, however to date this has not been reported for children exposed to airborne manganese. The objective of the present study was to examine behavioral traits among children with exposure to airborne manganese from a ferro-manganese alloy plant, located in the metropolitan region of Salvador, Brazil. The study included 34 boys and 36 girls, aged 7-12 years, living in two communities within a 3-km radius from the plant. For each child, hair manganese levels (MnH) and blood lead (PbB) levels were analyzed by graphite furnace atomic absorption spectrometry. The Children's Behavior Check List (CBCL) (Portuguese version validated in Brazil) was administered to parents or caregivers, providing scale scores of internalizing (withdrawn, somatic complaints, and anxious/depressed scales), externalizing (disruptive and aggressive) behaviors and a separate scale for attention problems. Median and range for MnH and PbB were 11.48 µg/g (range: 0.52-55.74); 1.1 µg/dL (range: 0.5-6.1), respectively. Spearman correlation analyses showed that several behavioral indices were significantly correlated with MnH levels for girls, but not for boys: total externalizing behavior (rho=0.484 vs rho=0.041) and attention problem scores (rho=0.542 vs rho=0.003) coefficients were significantly at p<0.001 level, respectively for girls and boys. No significant correlation was observed with any of the internalizing sub-scales. A linear regression model was fitted with the total externalizing behavior, inattention and total CBCL scores as dependent variables, with log transformed MnH stratified by sex, adjusting for age and maternal IQ. Total externalizing behaviors and attention problem scores were significantly associated with girls' MnH levels but not with boys'. Adjusting for maternal IQ, the ß-coefficients for LogMnH associations with total externalizing and attention problems are 8.85 (95%CI 2.44-15.24) and 4.03 (95%CI 1.50-6.56) for girls. For boys, after adjusting for age, the ß-coefficients are 0.08 (95%CI 11.51-11.66) and -0.05 (95%CI 4.34-4.25), respectively. The findings of this study suggest a positive association between elevated Mn exposure and externalizing behavioral problems and inattention, with girls presenting more pronounced effects. Future studies on Mn exposure in children should attempt to further elucidate sex and/or gender differences in Mn exposed populations.

Executive functioning and reading achievement in school: a study of Brazilian children assessed by their teachers as "poor readers".

This study examined executive functioning and reading achievement in 106 6- to 8-year-old Brazilian children from a range of social backgrounds of whom approximately half lived below the poverty line. A particular focus was to explore the executive function profile of children whose classroom reading performance was judged below standard by their teachers and who were matched to controls on chronological age, sex, school type (private or public), domicile (Salvador/BA or São Paulo/SP) and socioeconomic status. Children completed a battery of 12 executive function tasks that were conceptual tapping cognitive flexibility, working memory, inhibition and selective attention. Each executive function domain was assessed by several tasks. Principal component analysis extracted four factors that were labeled "Working Memory/Cognitive Flexibility," "Interference Suppression," "Selective Attention," and "Response Inhibition." Individual differences in executive functioning components made differential contributions to early reading achievement. The Working Memory/Cognitive Flexibility factor emerged as the best predictor of reading. Group comparisons on computed factor scores showed that struggling readers displayed limitations in Working Memory/Cognitive Flexibility, but not in other executive function components, compared to more skilled readers. These results validate the account that working memory capacity provides a crucial building block for the development of early literacy skills and extends it to a population of early readers of Portuguese from Brazil. The study suggests that deficits in working memory/cognitive flexibility might represent one contributing factor to reading difficulties in early readers. This might have important implications for how educators might intervene with children at risk of academic under achievement.

Noninvasive biomarkers of manganese exposure and neuropsychological effects in environmentally exposed adults in Brazil.

Manganese (Mn), an essential element to humans, in excess can cause neurotoxic damage. So far, Mn exposure assessment has no ideal biomarker. This study aims to investigate the association between Mn exposure, using noninvasive biomarkers, and neuropsychological effects in environmentally exposed adults. The residents of two communities near to a ferromanganese refinery in Bahia, Brazil were evaluated. Volunteers aged 15-55 of both sexes provided scalp hair, axillary hair, fingernail and saliva specimens for Mn determination by electrothermal absorption spectrometry. Several neuropsychological tests were used to evaluate cognitive, attention, memory, motor and executive functions. Significant correlations were observed between Mn in hair (MnH, median 8.95 µg/g), axillary hair (MnAxH,18.49 µg/g) and fingernail (MnFN, 6.91 µg/g) with the performances in several neuropsychological tests. No association was observed between manganese levels in saliva (MnSal, 4.2 µg/L) and any neuropsychological function. Multiple regression analysis detected an inverse association between Log MnH and IQ (ß=-4.76 [CI 95% -9.17 to -0.36]) and between Log MnFN and visual working memory (ß=-3.33 [CI 95% -6.15 to -0.52]). Direct association was observed between Log MnFN and time of completion in the cognitive flexibility task (ß=56.29 [CI 95% 2.41-110.18]). The Mn biomonitoring using noninvasive biomarkers was able to detect high exposure levels, which were associated with detrimental neuropsychological effects in adults exposed to industrial emissions.

Working memory and intelligence quotient: which best predicts on school achievement? / Memória de trabalho e quociente de inteligência: o que melhor prevê o desempenho escolar? / Memoria de trabajo y cociente de inteligencia: ¿cuál predice mejor el logro escolar?

Working memory (WM) refers to ability to store and manipulate information for a period of time. There is evidence of a close relationship between WM and learning. The aim of this study was to investigate the relationship between WM, intelligence quotient (IQ) on school achievement. Individual neuropsychological assessment was conducted following a specific protocol. The study included 227 children aged 7 to 12 years (M=9.87, SD=1.34), of which 119 were females, from private and public schools in Salvador, Bahia, Brazil. The data analysis included descriptive and inferential statistics. Academic achievement was evaluated using the Academic Performance Test (TDE), with subtests in reading, writing and arithmetic. The components of WM were evaluated using backward and forward Digit Span tasks and the backward and forward Corsi block-tapping task. The estimated IQ was assessed using tasks vocabularies and block design of the Wechsler scales. The statistical tests used were linear regression analysis (stepwise) and Pearson correlation. The results showed that the best predictors of academic performance were Digit Span Forward, Corsi Block Backward and Digit Span Backward task. The hypothesis of non-multicollinearity was tested, and it was verified that the constructs were independent (VIF <10 and Tolerance >0.20). The variance in academic performance explained by WM model was ΔR=0.36. High and significant correlations were observed between the components of WM and the TDE. The WM score (Digit Span Backward + Corsi Block Backward) and the TDE were correlated (r=0.54**). These results indicate that WM is a good predictor of academic achievement than IQ and are consistent with other findings showing WM as a predictor of learning or the potential for learning. This result has important implications for education, particularly with respect to intervention.

Memória de trabalho (MT) refere-se a capacidade de armazenar e manipular informações por um período de tempo. Há evidências de uma estreita relação entre MT e aprendizado. O objetivo deste estudo foi investigar a relação entre MT, quociente de inteligência (QI) no desempenho acadêmico. A avaliação neuropsicológica individual foi realizada seguindo um protocolo específico. O estudo incluiu 227 crianças com idades entre 7 a 12 anos (M=9.87, SD=1.34), das quais 119 eram do sexo feminino, de escolas privadas e públicas em Salvador, Bahia, Brasil. A análise de dados incluiu estatística descritiva e inferencial. O desempenho acadêmico foi avaliado usando o Teste de Desempenho Escolar (TDE), com subtestes de leitura, escrita e aritmética. Os componentes da MT foram avaliados usando tarefas de Span de Digitos e direta e inversa e a tarefa de Blocos de Corsi versão direta e inversa. O IQ estimado foi avaliado usando as tarefas de vocabulário e cubos das escalas Wechsler. Os testes estatísticos utilizados foram análise de regressão linear (enter) e correlação de Pearson. Os resultados mostraram que os melhores preditores de desempenho escolar foram as tarefas Digitos span direto, invertido e Cubos de Corsi direto e inverso. A hipótese de não-multicolinearidade foi testada, e verificou-se que os construtos foram independentes (VIF <10 e tolerância> 0,20). A variância no desempenho acadêmico explicado pelo modelo WM foi ΔR=0,12. Correlações significativas foram observadas entre os componentes da MT e do TDE. O escore da MT (Dígito span do inverso + Corsi Block inverso) e o TDE foram correlacionados (r=0,28 **). Estes resultados indicam que a MT é um bom preditor de realização escolar do que o QI e são consistentes com outros achados mostrando MT como um preditor de aprendizagem ou o potencial de aprendizagem. Este resultado tem implicações importantes para a educação, particularmente no que diz respeito à intervenção.

La memoria de trabajo (WM) se refiere a la capacidad de almacenar y manipular información durante un período de tiempo, y existe evidencia de una relación cercana entre la memoria de trabajo y el aprendizaje. El objetivo de este estudio fue investigar la relación entre la memoria de trabajo, la inteligencia (IQ) y el rendimiento escolar. La evaluación individual se realizó siguiendo un protocolo específico. El logro escolar se evaluó mediante la prueba de Logro escolar (TDE), con subpruebas en lectura, escritura y aritmética. Los componentes de la memoria de trabajo se evaluaron utilizando versiones anteriores y posteriores de Digit Span y las pruebas de bloqueo de tapado de Corsi. El IQ estimado se evaluó mediante las subpruebas Vocabulary and Block Design de Wechsler Intelligence Scale for Children III. El estudio incluyó a 227 niños de 7 a 12 años (M=9.87, SD=1.34), de los cuales 119 eran mujeres, de escuelas privadas y públicas en Salvador, Bahía, Brasil. El análisis de los datos incluyó estadística descriptiva e inferencial. Las pruebas estadísticas utilizadas fueron el análisis de regresión lineal (enter) y la correlación de Pearson. Los resultados mostraron que los mejores predictores de Logros Escolares fueron el Digit Span hacia adelante, hacia atrás y Corsi bloquean las tareas hacia adelante y hacia atrás. Se probó la hipótesis de no multicolinealidad y se verificó que las construcciones eran independientes (VIF <10 y Tolerancia >0.20). La variación en el rendimiento académico explicada por el modelo de memoria de trabajo fue ΔR=0.12. Se observaron correlaciones significativas entre los componentes de la memoria de trabajo y el TDE. La puntuación de la memoria de trabajo (Digit Span Backward + Corsi Block Backward) y el TDE se correlacionaron (r=0.28 **). Estos resultados indican que la memoria de trabajo es un buen predictor del rendimiento escolar que el coeficiente intelectual y es consistente con otros hallazgos que muestran que la memoria de trabajo es un predictor del aprendizaje o el potencial de aprendizaje. Este resultado tiene implicaciones importantes para la educación, particularmente con respecto a la intervención.