Nayara Argollo

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. Spearmans 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 (β=-9.67; 95%CI=-16.97 to -2.37), Block Design (β=-2.50; 95%CI=-3.91 to -1.10) and Digit Span Total (β=-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 (β=-1.32=95%CI=-2.23 to -0.40; β=-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.

Transcranial Direct Current Stimulation in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder (ADHD): A Pilot Study

Studies investigating the possible benefits of transcranial direct current stimulation on left dorsolateral prefrontal cortex in children and adolescents with attention-deficit hyperactivity disorder (ADHD) have not been performed. This study assesses the effect of transcranial direct current stimulation in children and adolescents with ADHD on neuropsychological tests of visual attention, visual and verbal working memory, and inhibitory control. An auto-matched clinical trial was performed involving transcranial direct current stimulation in children and adolescents with ADHD, using SNAP-IV and subtests Vocabulary and Cubes of the Wechsler Intelligence Scale for Children III (WISC-III). Subjects were assessed before and after transcranial direct current stimulation sessions with the Digit Span subtest of the WISC-III, inhibitory control subtest of the NEPSY-II, Corsi cubes, and the Visual Attention Test (TAVIS-3). There were 9 individuals with ADHD according to Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition) criteria. There was statistically significant difference in some aspects of TAVIS-3 tests and the inhibitory control subtest of NEPSY-II. Transcranial direct current stimulation can be related to a more efficient processing speed, improved detection of stimuli, and improved ability to switch between an ongoing activity and a new one.

Medidas do índice de resistência ao Doppler craniano em recém-nascidos pré-termo com lesão da substância branca cerebral

OBJECTIVE: To investigate whether the resistance index (RI) within the first 72 hours of life of newborn infants with cerebral white matter lesion (WML) is correlated with the adverse outcome of WML. METHODS: Retrospective study. Newborn infants with WML were identified based on cranial ultrasound results, and those with Doppler imaging and RI measurement were selected. The newborn infants were placed in three groups: low ( 0.85) RI. The sample was analyzed as a whole at first and then stratified according to birth weight. RESULTS: According to the RI, cerebral blood flow was abnormal in 46 (68.7%) patients, low in 42 (62.7%), and high in four (6%). Among those with a low RI, 15 (35.7%) had an adverse outcome, with ultrasonographic signs of cerebral atrophy in 10 (23.8%) and intraventricular hemorrhage in five (11.9%) patients. The four newborn infants with a high RI also had an adverse outcome, one (25%) with signs of cerebral atrophy and three (75%) with intraventricular hemorrhage. No statistically significant differences were observed between RI groups and the group with a fatal outcome. CONCLUSION: The study showed that abnormal RI within the first 72 hours was associated with healing complications in newborn infants with cerebral WML. Abnormal RI results were not correlated with the fatal outcome. Therefore, RI is an important parameter that should be measured in newborn infants.

Cranial Doppler resistance index measurement in preterm newborns with cerebral white matter lesion.

OBJECTIVE To investigate whether the resistance index (RI) within the first 72 hours of life of newborn infants with cerebral white matter lesion (WML) is correlated with the adverse outcome of WML. METHODS Retrospective study. Newborn infants with WML were identified based on cranial ultrasound results, and those with Doppler imaging and RI measurement were selected. The newborn infants were placed in three groups: low (< 0.61), normal (0.61-0.85) or high (> 0.85) RI. The sample was analyzed as a whole at first and then stratified according to birth weight. RESULTS According to the RI, cerebral blood flow was abnormal in 46 (68.7%) patients, low in 42 (62.7%), and high in four (6%). Among those with a low RI, 15 (35.7%) had an adverse outcome, with ultrasonographic signs of cerebral atrophy in 10 (23.8%) and intraventricular hemorrhage in five (11.9%) patients. The four newborn infants with a high RI also had an adverse outcome, one (25%) with signs of cerebral atrophy and three (75%) with intraventricular hemorrhage. No statistically significant differences were observed between RI groups and the group with a fatal outcome. CONCLUSION The study showed that abnormal RI within the first 72 hours was associated with healing complications in newborn infants with cerebral WML. Abnormal RI results were not correlated with the fatal outcome. Therefore, RI is an important parameter that should be measured in newborn infants.

Aspectos clínico-epidemiológicos das neoplasias cerebrais na faixa etária pediátrica no Estado da Bahia, Brasil

The aim of this study is to describe the relevant aspects of the medical treatment and epidemiology of brain tumors in children between 1 and 15 years old in the State of Bahia, Brazil, first semester of 1995. A cross-sectional design was used for the survey of all new cases and preexisting cases of brain tumors diagnosed through neuroimage among all the children who completed these examinations. Forty eight out of 2 128 were diagnosed as brain tumors, 19 of which being incident cases. In the clinical epidemiological study, the prevalence was 2.3 percent, and the incidence was 0.9 percent. In the prevalent cases, males predominated (1.4:1), and the average age of 10-15 years old (65 %). Among the 1-4 years old group predominated incident cases. The astrocytoma was the most frequent brain tumor (41%), and the supratentorial localization predominated by 52%. The ataxia and/or paralysis of cranial nerve and the endocrine and/or visual disturbance symptomatic groups were the most prevalent (82% and 43%, respectively). We discuss the supratentorial localization and the adolescent group predomination in cerebral neoplasms in childhood.

Estimativa da prevalência de neoplasia cerebral na faixa etária pediátrica pelo método de captura-recaptura

The aim of the study was to estimate the prevalence and fatality rate of primary cerebral neoplasms among children between 1 and 15 years old, State of Bahia, Brazil,1995. It was a cross-sectional study which includes all cases of brain tumors diagnosed by several sources. From these cases the capture-recapture method was used to estimate the probable number of cases and measure the prevalence and confidence intervals at 95%. By this method it was estimated the existence of 87 cases (CI = 64 ; 111) of brain tumores in the State, being 72 (CI = 54 ; 91) in the capital. The estimated prevalence was 1.85/100 000 for children between 1 to 15 years old (CI = 1.36 ; 2.36/100 000) for the State, and 10.1/100,000 (CI = 7.58 ; 12.77/100,000) for the capital. The fatality rate was 5.4 percent (CI = 4% ; 8%), and 8.9% (CI = 7% ; 13%) for the capital and the State respectively. The capture-recapture method showed high precision to estimate the total number of cases. Possible causes of no diagnostic nor treatment of cerebral neoplasms are discussed.

Complicações neurológicas em anemia falciforme: avaliação neuropsicológica do desenvolvimento com o NEPSY

Estudo de caso de duas criancas portadoras de anemia falciforme, com complicacoes neurologicas. Utilizou-se uma ampla bateria neuropsicologica - NEPSY. Uma crianca apresentou acidente vascular cerebral com paresia de hemicorpo esquerdo, e a outra, ataque isquemico transitorio. As avaliacoes neuropsicologicas demonstraram que havia extenso prejuizo cognitivo no primeiro caso, em contraste com comprometimento leve no segundo. Baixas pontuacoes nas funcoes de atencao visual, memoria operacional, linguagem, flexibilidade cognitiva, habilidades sensorio-motora, visoespacial e viso-construtiva. Rebaixamento intelectual e no desempenho academico foram encontrados no paciente que sofreu o acidente isquemico. A crianca que foi acometida por ataque isquemico transitorio apresentou dispraxia motora e oromotora, diminuicao da atencao visual e memoria verbal. Estes achados corroboram com os dados encontrados na literatura e reforcam a relevância de conhecer a tipologia destas alteracoes para intervir precocemente na deficiencia cognitiva, minimizando as repercussoes no desenvolvimento cognitivo, academico e psicossocial.

Comprehensive neuropsychological evaluation of children and adolescents with sickle cell anemia: a hospital-based sample

Background Individuals with sickle cell anemia may suffer symptomatic or silent cerebral infarcts leading to neurocognitive complications. This study investigated the cognitive and intellectual performance of children and adolescents with sickle cell anemia. Methods The socioeconomic status, clinical aspects and behavioral profile of 15 young individuals with sickle cell anemia were evaluated. The Wechsler Intelligence Scale for Children, the Developmental Neuropsychological Assessment Test, and the Child Behavior Checklist were applied. Results Participants with a history of stroke had lower intelligence quotient (IQ) scores. Alterations were found in attention and executive functioning, language, verbal and visual memory, visuospatial processing and sensorimotor skills. These alterations were found both in the children and adolescents who had had a cerebral infarction and in those who apparently had not. In the majority of cases, there were learning difficulties, a history of repeating school years and a need for specialist educational support. The most common additional diagnoses in accordance with the Diagnostic and Statistical Manual of Mental Disorders IV were depressive disorder, anxiety disorder and somatic disorder, as well as conditions associated with physical and psychosocial repercussions of sickle cell anemia. Conclusion As sickle cell anemia is considered a progressive cerebral vasculopathy, it is a potential risk factor for neurocognitive and psychosocial development. Therefore, periodic neuropsychological and behavioral evaluations of children and adolescents with sickle cell anemia may represent a useful measure to reduce long-term biopsychosocial repercussions.

Peso de nascimento como preditor para a gravidade da lesão da substância branca cerebral neonatal

Para analisar a associacao entre fatores natais com a gravidade da lesao da substância branca (LSB) cerebral neonatal, controlando o peso de nascimento, identificaram os neonatos pela ultra-sonografia craniana, que foram divididos em: aqueles com evolucao da LSC para resolucao da imagem ao ultra-som (menor gravidade) e, aqueles que evoluiram com formacao de cistos e/ou ventriculomegalia e/ou hemorragia (maior gravidade). Doze variaveis (hiponatremia, anemia, infeccao, retinopatia, displasia broncopulmonar, hipoalbuminemia, persistencia do canal arterial, audiometria alterada, desconforto respiratorio precoce, peso de nascimento <2500g, peso por categoria e prematuridade) tiveram diferencas entre os dois grupos (p<0,05), sendo que 9 (hiponatremia, infeccao, retinopatia, hipoalbuminemia, persistencia do canal arterial, desconforto respiratorio precoce, baixo peso, prematuridade e peso por categorias) se mantiveram estatisticamente diferentes (p<0,01) apos analise por regressao logistica. Quando analisadas por categoria de peso de nascimento, nenhuma variavel demonstrou significância estatistica. O estudo sugere que o peso de nascimento e o maior fator - provavelmente o unico - associado com gravidade da LSB cerebral neonatal.

Performance comparison between right-handers and left-handers in a brazilian sample of the developmental neuropsychological assessment

Studies that investigate handedness are performed in order to relate hemispheric specialization and cognitive performance. The aim of study was compare the neuropsychological performance between right-handed and left-handed children with ages from five to six years who participated in the Brazilian study of standardization of the Developmental Neuropsychological Assessment. For analysis of socio-demographic characteristics, descriptive statistics were used. To compare the mean scores between the groups, normality was tested using Analysis of Variance (one-way Anova) and the Kruskal-Wallis test. When comparing right-handed and left-handed children with typical development, left-handed children presented poorer performance on the subtests involving Attention and Executive Functioning, Language, and Learning and Memory.