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1.
Neuropsychologia ; 51(9): 1684-92, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23707683

RESUMO

The planum temporale is a highly lateralized cortical region, located within Wernicke's area, which is thought to be involved in auditory processing, phonological processing, and language. Research has linked abnormal morphology of the planum temporale to developmental dyslexia, although results have varied in large part due to methodological inconsistencies in the literature. This study examined the asymmetry of the planum temporale in 29 children who met criteria for dyslexia and 26 children whose reading was unimpaired. Leftward asymmetry of the planum temporale was found in the total sample and this leftward asymmetry was significantly reduced in children with dyslexia. This reduced leftward asymmetry in children with dyslexia was due to a planum temporale that is larger in the right hemisphere. This study lends support to the idea that planum temporale asymmetry is altered in children with developmental dyslexia.


Assuntos
Dislexia/patologia , Inteligência/fisiologia , Fonética , Leitura , Lobo Temporal/patologia , Adolescente , Criança , Dislexia/fisiopatologia , Feminino , Humanos , Testes de Inteligência , Imageamento por Ressonância Magnética , Masculino
2.
Dev Neuropsychol ; 37(7): 617-35, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23066939

RESUMO

It is unclear the extent to which neurodevelopmental differences observed in reading disabled individuals are limited to traditional language processing areas. Some have suggested atypical processing of complex spatial problems in these individuals. Hitherto, research on this question has been limited to behavioral studies, yielding mixed results. Absence of related imaging studies is in stark contrast to the plethora examining functional neurology for verbal tasks. This study uses functional magnetic resonance imaging (fMRI) to examine how adult dyslexics perform when analyzing complex spatial material unrelated to the reading of text. We observed atypical functional neurology during spatial problem solving, which was not observed behaviorally.


Assuntos
Mapeamento Encefálico , Encéfalo/irrigação sanguínea , Dislexia/patologia , Dislexia/fisiopatologia , Fonética , Resolução de Problemas/fisiologia , Percepção Espacial/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Oxigênio/sangue , Estimulação Luminosa , Psicometria , Tempo de Reação , Leitura , Vocabulário , Adulto Jovem
3.
Behav Genet ; 42(4): 509-27, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22426781

RESUMO

Inspired by the localization, on 15q21.2 of the CYP19A1 gene in the linkage region of speech and language disorders, and a rare translocation in a dyslexic individual that was brought to our attention, we conducted a series of studies on the properties of CYP19A1 as a candidate gene for dyslexia and related conditions. The aromatase enzyme is a member of the cytochrome P450 super family, and it serves several key functions: it catalyzes the conversion of androgens into estrogens; during early mammalian development it controls the differentiation of specific brain areas (e.g. local estrogen synthesis in the hippocampus regulates synaptic plasticity and axonal growth); it is involved in sexual differentiation of the brain; and in songbirds and teleost fishes, it regulates vocalization. Our results suggest that variations in CYP19A1 are associated with dyslexia as a categorical trait and with quantitative measures of language and speech, such as reading, vocabulary, phonological processing and oral motor skills. Variations near the vicinity of its brain promoter region altered transcription factor binding, suggesting a regulatory role in CYP19A1 expression. CYP19A1 expression in human brain correlated with the expression of dyslexia susceptibility genes such as DYX1C1 and ROBO1. Aromatase-deficient mice displayed increased cortical neuronal density and occasional cortical heterotopias, also observed in Robo1-/- mice and human dyslexic brains, respectively. An aromatase inhibitor reduced dendritic growth in cultured rat neurons. From this broad set of evidence, we propose CYP19A1 as a candidate gene for human cognitive functions implicated in reading, speech and language.


Assuntos
Aromatase/genética , Encéfalo/crescimento & desenvolvimento , Dislexia/genética , Transtornos da Linguagem/genética , RNA Mensageiro/análise , Distúrbios da Fala/genética , Animais , Aromatase/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Estudos de Coortes , Proteínas do Citoesqueleto , Dislexia/metabolismo , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Transtornos da Linguagem/metabolismo , Masculino , Camundongos , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Polimorfismo de Nucleotídeo Único , Regiões Promotoras Genéticas , Locos de Características Quantitativas , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Distúrbios da Fala/metabolismo , Translocação Genética , Proteínas Roundabout
4.
Ann Dyslexia ; 60(1): 1-17, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20033795

RESUMO

The current investigation explored the diagnostic utility of reading fluency measures in the identification of children with reading disabilities. Participants were 50 children referred to a university-based clinic because of suspected reading problems and/or a prior diagnosis of dyslexia, where children completed a battery of standardized intellectual, reading achievement, and processing measures. Within this clinical sample, a group of children were identified that exhibited specific deficits in their reading fluency skills with concurrent deficits in rapid naming speed and reading comprehension. This group of children would not have been identified as having a reading disability according to assessment of single word reading skills alone, suggesting that it is essential to assess reading fluency in addition to word reading because failure to do so may result in the under-identification of children with reading disabilities.


Assuntos
Dislexia/diagnóstico , Dislexia/psicologia , Leitura , Criança , Comportamento Infantil/psicologia , Desenvolvimento Infantil/fisiologia , Cognição , Compreensão , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Escalas de Wechsler
5.
Brain Lang ; 111(1): 46-54, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19356794

RESUMO

Limited research has been conducted on the structure of the pars triangularis (PT) in dyslexia despite functional neuroimaging research finding it may play a role in phonological processing. Furthermore, research to date has not examined PT size in ADHD even though the right inferior frontal region has been implicated in the disorder. Hence, one of the purposes of this study was to examine the structure of the PT in dyslexia and ADHD. The other purposes included examining the PT in relation to overall expressive language ability and in relation to several specific linguistic functions given language functioning often is affected in both dyslexia and ADHD. Participants included 50 children: 10 with dyslexia, 15 with comorbid dyslexia/ADHD, 15 with ADHD, and 10 controls. Using a 2 (dyslexia or not) x 2 (ADHD or not) MANCOVA, findings revealed PT length and shape were comparable between those with and without dyslexia. However, children with ADHD had smaller right PT lengths than those without ADHD, and right anterior ascending ramus length was related to attention problems in the total sample. In terms of linguistic functioning, presence of an extra sulcus in the left PT was related to poor expressive language ability. In those with adequate expressive language functioning, left PT length was related to phonological awareness, phonological short-term memory and rapid automatic naming (RAN). Right PT length was related to RAN and semantic processing. Further work on PT morphology in relation to ADHD and linguistic functioning is warranted.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Dislexia/fisiopatologia , Lobo Frontal/patologia , Lobo Frontal/fisiopatologia , Análise de Variância , Transtorno do Deficit de Atenção com Hiperatividade/complicações , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Criança , Manual Diagnóstico e Estatístico de Transtornos Mentais , Dislexia/complicações , Dislexia/patologia , Feminino , Humanos , Idioma , Testes de Linguagem , Linguística , Imageamento por Ressonância Magnética , Masculino , Memória de Curto Prazo/fisiologia , Testes Neuropsicológicos , Tamanho do Órgão , Comportamento Verbal/fisiologia
6.
J Child Neurol ; 24(4): 438-48, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19211921

RESUMO

Because poor comprehension has been associated with small cerebral volume and there is a high comorbidity between developmental dyslexia, attention-deficit hyperactivity disorder (ADHD), and specific language impairment, the goal of this study was to determine whether cerebral volume is reduced in dyslexia and attention-deficit hyperactivity disorder in general, as some suggest, or whether the reduction in volume corresponds to poor receptive language functioning, regardless of the diagnosis. Participants included 46 children with and without dyslexia and attention-deficit hyperactivity disorder, aged 8 to 12 years. Our results indicated that cerebral volume was comparable between those with and without dyslexia and attention-deficit hyperactivity disorder overall. However, when groups were further divided into those with and without receptive language difficulties, children with poor receptive language had smaller volumes bilaterally as hypothesized. Nonetheless, the relationship between cerebral volume and receptive language was not linear; rather, our results suggest that small volume is associated with poor receptive language only in those with the smallest volumes in both dyslexia and attention-deficit hyperactivity disorder.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Córtex Cerebral/anormalidades , Dislexia/etiologia , Dislexia/patologia , Malformações do Sistema Nervoso/complicações , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Causalidade , Córtex Cerebral/fisiopatologia , Criança , Dislexia/fisiopatologia , Feminino , Lateralidade Funcional/fisiologia , Humanos , Idioma , Testes de Linguagem , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Tamanho do Órgão/fisiologia , Valor Preditivo dos Testes , Percepção da Fala/fisiologia , Comportamento Verbal/fisiologia
7.
J Child Neurol ; 23(4): 368-80, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18160557

RESUMO

Recent evidence suggests that the primary source of dysfunction in dyslexia is the cerebellum. To examine the cerebellar deficit hypothesis of dyslexia, 20 children with dyslexia and 20 children without dyslexia were assessed using neuropsychological testing and quantitative magnetic resonance imaging. Results demonstrated that the volumes of both hemispheres and the vermis were not statistically significantly different between groups. However, children without dyslexia demonstrated greater rightward cerebellar hemisphere asymmetry. The relationship between cerebellar morphologic structure and phonological processing was assessed. For children without dyslexia, bilateral hemisphere volume moderately correlated with phonological awareness and phonological short-term memory. Hemisphere asymmetry moderately correlated with rapid naming errors, and the anterior vermis volume moderately correlated with phonological awareness. For children with dyslexia, the only statistically significant correlation was between rapid naming errors and the left hemisphere volume. Evidence suggests that atypical cerebellar morphologic structure may have a role in dyslexia for a subgroup of individuals. Although children with and without attention-deficit/hyperactivity disorder did not differ in cerebellar morphologic structure, the anterior vermis volume moderately correlated with inattention, hyperactivity, and impulsivity, while the right hemisphere volume moderately correlated with inattention and hyperactivity. Our findings provide mixed support for the cerebellar deficit hypothesis of dyslexia. Although cerebellar morphologic structure is atypical in some individuals with dyslexia, it is inconsistently related to cognitive or motor dysfunction. In our sample, cerebellar morphologic structure may be related to about one-third of cases of dyslexia. Hence, dyslexia may be best accounted for by a combination of cortical and cerebellar contributions.


Assuntos
Córtex Cerebelar/patologia , Córtex Cerebelar/fisiopatologia , Dislexia/patologia , Dislexia/fisiopatologia , Imageamento por Ressonância Magnética , Transtornos da Articulação/etiologia , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Conscientização , Cerebelo/patologia , Cerebelo/fisiopatologia , Criança , Feminino , Lateralidade Funcional , Humanos , Masculino , Memória de Curto Prazo , Testes Neuropsicológicos
8.
Neuropsychology ; 21(2): 235-41, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17402823

RESUMO

This study examines the corpus callosum in 68 readers nested in 24 families. Callosa were measured and controlled for whole brain volume, intelligence, and gender. The relation of corpus callosum size to the within-family variance of oral reading was investigated with various measurements: volume, midsagittal area, and anterior-to-posterior one-fifth area segmentations. Because this is the first known publication of MRI calculations of corpus callosum volume, some basic questions about bilateral symmetry and the efficacy of area versus volumetric measurements were explored. Results suggest that better readers within families have larger midsagittal areas at the midbody. Although reliably measured, volume did not contribute to oral reading but was highly correlated with area. Bilateral volumes of the corpus callosum were symmetric.


Assuntos
Mapeamento Encefálico , Corpo Caloso/anatomia & histologia , Corpo Caloso/fisiologia , Relações Familiares , Imageamento por Ressonância Magnética , Leitura , Adolescente , Adulto , Criança , Dominância Cerebral/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Testes de Inteligência/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade
9.
J Child Neurol ; 21(2): 139-44, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16566878

RESUMO

Social comprehension involves empathy for others' experiences and appropriate responses to nonverbal cues. Previous research using magnetic resonance imaging (MRI) has suggested a relationship between brain morphology and psychiatric syndromes, such as attention-deficit hyperactivity disorder (ADHD), that typically entail social difficulties. The right hemisphere, specifically, has been associated with social skill deficits, and numerous studies have also associated ADHD with social skill deficits. No studies, however, have examined the association of ADHD subtype with both social comprehension and right-hemisphere morphology. Fifty-nine children (6-12 years old) underwent MRI, from which the right hemisphere was classified into four morphologic subtypes. Children were also grouped by ADHD subtype or clinical control status. From Behavior Assessment System for Children (BASC) items, a social comprehension subscale was constructed. Analyses revealed significant differences in social comprehension based on ADHD subtype. Differences in social comprehension based on ADHD status were especially pronounced in children with atypical right-hemisphere morphology. Thus, the diagnosis of ADHD might be associated with underlying risk in the area of social comprehension, especially for children with atypical right-hemisphere morphology.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Compreensão , Dominância Cerebral/fisiologia , Empatia , Giro do Cíngulo/patologia , Imageamento por Ressonância Magnética , Transtornos do Comportamento Social/diagnóstico , Socialização , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Criança , Feminino , Humanos , Relações Interpessoais , Deficiências da Aprendizagem/diagnóstico , Deficiências da Aprendizagem/fisiopatologia , Deficiências da Aprendizagem/psicologia , Masculino , Testes Neuropsicológicos , Fatores de Risco , Transtornos do Comportamento Social/fisiopatologia , Transtornos do Comportamento Social/psicologia
10.
Cortex ; 42(8): 1107-18, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17209416

RESUMO

Behavioral research suggests that individuals with dyslexia may have exceptional skills in nonverbal cognitive processes, while genetic studies have noted that giftedness, high IQ and/or special talents tend to run in families. Taken together, these results suggest that persons within families (particularly offspring) may share similar cortical systems supporting those functions. Postmortem and in vivo imaging studies have linked dyslexia to abnormalities in the structures associated with the parietal operculum (PO) (e.g., planum temporale, supramarginal gyrus, and angular gyrus). In this paper we present data on a single family showing a link between dyslexia, superior nonverbal IQ and atypical PO presentation. We consider the psychometric and neurological patterns of this family as a tentative etiological test of the putative dyslexia-talent association.


Assuntos
Encéfalo/patologia , Encéfalo/fisiologia , Dislexia/patologia , Dislexia/psicologia , Inteligência/genética , Inteligência/fisiologia , Adolescente , Adulto , Córtex Cerebral/patologia , Córtex Cerebral/fisiologia , Criança , Cognição/fisiologia , Dislexia/genética , Escolaridade , Feminino , Lateralidade Funcional/fisiologia , Humanos , Testes de Inteligência , Idioma , Imageamento por Ressonância Magnética , Masculino , Memória/fisiologia , Memória de Curto Prazo/fisiologia , Processos Mentais/fisiologia , Lobo Parietal/fisiologia , Linhagem , Psicolinguística , Comportamento Verbal , Percepção Visual/fisiologia , Escalas de Wechsler
11.
Ann Dyslexia ; 56(1): 83-102, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17849209

RESUMO

The double-deficit hypothesis of dyslexia posits that reading deficits are more severe in individuals with weaknesses in phonological awareness and rapid naming than in individuals with deficits in only one of these reading composite skills. In this study, the hypothesis was tested in an adult sample as a model of reading achievement. Participants were parents of children referred for evaluation of reading difficulties. Approximately half of all participants reported difficulty learning to read in childhood and a small subset demonstrated ongoing weaknesses in reading. Structural equation modeling results suggest that the double-deficit hypothesis is an accurate model for understanding adult reading achievement. Better reading achievement was associated with better phonological awareness and faster rapid automatized naming in adults. Posthoc analyses indicated that individuals with double deficits had significantly lower reading achievement than individuals with single deficits or no deficits.


Assuntos
Conscientização , Dislexia/diagnóstico , Fonética , Leitura , Adulto , Criança , Compreensão , Dislexia/genética , Escolaridade , Feminino , Humanos , Deficiências da Aprendizagem/diagnóstico , Deficiências da Aprendizagem/genética , Masculino , Pessoa de Meia-Idade , Pais/psicologia , Tempo de Reação , Estatística como Assunto , Estados Unidos , Aprendizagem Verbal
12.
Neuropsychol Rev ; 15(2): 59-71, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16211466

RESUMO

The corpus callosum is the major neural pathway that connects homologous cortical areas of the two cerebral hemispheres. The nature of how that interhemispheric connection is manifested is the topic of this review; specifically, does the corpus callosum serve to communicate an inhibitory or excitatory influence on the contralateral hemisphere? Several studies take the position that the corpus callosum provides the pathway through which a hemisphere or cortical area can inhibit the other hemisphere or homologous cortical area in order to facilitate optimal functional capacity. Other studies suggest that the corpus callosum integrates information across cerebral hemispheres and thus serves an excitatory function in interhemispheric communication. This review examines these two contrasting theories of interhemispheric communication. Studies of callosotomies, callosal agenesis, language disorders, theories of lateralization and hemispheric asymmetry, and comparative research are critically considered. The available research, no matter how limited, primarily supports the notion that the corpus callosum serves a predominantly excitatory function. There is evidence, however, to support both theories and the possibility remains that the corpus callosum can serve both an inhibitory and excitatory influence on the contralateral hemisphere.


Assuntos
Nível de Alerta/fisiologia , Encéfalo/fisiologia , Cognição/fisiologia , Corpo Caloso/fisiologia , Lateralidade Funcional/fisiologia , Inibição Neural/fisiologia , Transferência de Experiência , Comunicação Celular , Humanos , Rede Nervosa/fisiologia
13.
J Child Neurol ; 19(4): 282-9, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15163095

RESUMO

Developmental Gerstmann's syndrome is a neurodevelopmental disorder infrequently described in the literature. The limited literature might result from controversy surrounding developmental Gerstmann's syndrome as a "true syndrome." Developmental Gerstmann's syndrome requires a tetrad of symptoms: left-right confusion, finger agnosia, dyscalculia, and dysgraphia, with constructional dyspraxia often included as a fifth symptom. The etiology of developmental Gerstmann's syndrome is unknown, but several hypotheses have been proposed, and none have been conclusively confirmed. Based on the paucity of recent research on developmental Gerstmann's syndrome, individuals who meet the criteria for the disorder could be given other diagnoses. A clustering of neuropsychologic features across other seemingly related disorders suggests that the conceptualization of the tetrad of symptoms traditionally associated with developmental Gerstmann's syndrome more appropriately reflects soft signs that are commonly associated with a number of other neurodevelopmental disorders. Thus, although developmental Gerstmann's syndrome is of historical interest to neurodevelopmental specialists, there appears to be no basis for considering this disorder as a unique syndrome.


Assuntos
Síndrome de Gerstmann/diagnóstico , Diagnóstico Diferencial , Humanos
14.
Brain Lang ; 89(1): 122-35, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15010244

RESUMO

Although children with neurodevelopmental disorders frequently present with reduced short-term memory functioning, the relationship between perisylvian morphology and verbal short-term memory functioning has received limited attention. Thus, examining this relationship in children with neurodevelopmental disorders was the focus of this exploratory study. Results suggested leftward asymmetry in the temporal bank of the planum temporale is related to better coding and storage of semantic material. In contrast, parietal bank morphology is related to coding and storage of phonological material, and presence of an extra gyrus in the parietal region is associated with reduced phonological working memory. Data also supported a relationship between pars triangularis morphology and verbal short-term memory functioning, but this is not material-specific.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Aqueduto do Mesencéfalo/patologia , Dominância Cerebral/fisiologia , Dislexia/diagnóstico , Memória de Curto Prazo/fisiologia , Lobo Parietal/patologia , Lobo Temporal/patologia , Aprendizagem Verbal/fisiologia , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Criança , Dislexia/patologia , Feminino , Humanos , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Transtornos do Desenvolvimento da Linguagem/patologia , Masculino , Fonética , Semântica , Estatística como Assunto
15.
Pediatrics ; 112(2): 324-31, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12897282

RESUMO

OBJECTIVE: We examined the relationship between cerebral blood flow velocity, measured by transcranial Doppler (TCD) ultrasonography, and neurocognitive functioning. METHODS: Participants were 60 children who had sickle cell disease (HbSS) and had no documented history of stroke. Children were classified according to Stroke Prevention Trial in Sickle Cell Anemia criteria (normal, conditional, and abnormal), and their performance was compared on measures of intellectual abilities, academic achievement, sustained attention/concentration, executive function, and parent and teacher ratings of executive function. RESULTS: Children with abnormal TCD values performed more poorly than children with conditional TCD values on measures of verbal intelligence and executive function. Children with conditional TCD values performed more poorly than children with normal TCD values on measures of sustained attention/concentration and executive function. TCD values also were a significant predictor of auditory working memory in exploratory analyses. CONCLUSIONS: Our findings support the hypothesis that neurocognitive functions subserved by the frontal systems (eg, sustained attention/concentration and executive function) seem to be the most useful indices of progressive cerebrovasculopathy in children with HbSS disease.


Assuntos
Anemia Falciforme/psicologia , Circulação Cerebrovascular , Cognição , Adolescente , Anemia Falciforme/diagnóstico por imagem , Anemia Falciforme/fisiopatologia , Velocidade do Fluxo Sanguíneo , Criança , Feminino , Humanos , Inteligência , Masculino , Análise Multivariada , Testes Psicológicos , Análise de Regressão , Fatores Socioeconômicos , Ultrassonografia Doppler Transcraniana
16.
J Child Neurol ; 17(2): 97-105, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11952084

RESUMO

Magnetic resonance imaging (MRI) studies of the caudate nucleus have reported reversal asymmetry and alterations of its size, suggesting a striate cortical disorder related to attention-deficit hyperactivity disorder (ADHD). The objective was to evaluate whether alterations of the asymmetry and size of the caudate nucleus head exist in a sample of well-controlled 7- to 11-year-old Colombian children, with different types of ADHD. Two groups of cases-ADHD of the combined type and ADHD of the inattentive type-and one control group, were selected. Multiple methods for assessing ADHD (rating scales, psychologic.interview, neurologic history and examination, and neuropsychologic evaluation) were used to confirm the diagnoses. Participants with a history of language disorder, learning disabilities, depression, and other major neurologic and psychiatric conditions were excluded. Finally all groups had 15 children, matched by sex (7 male, 8 female), age, socioeconomic status, and grade. Height, weight, head circumference, and encephalic index were statistically controlled. Three T1-weighted volumetric (three-dimensional) MRI slides of the caudate nucleus head were obtained with a 1.5-Tesla Gyroscan apparatus. The control group had a significantly higher Wechsler Full-Scale IQ than the groups with ADHD of the combined type and ADHD of the inattentive type (P < .001). Volumes from the left caudate nucleus head were significantly larger than volumes from the right in all groups (P < .001). There were no group differences when volumes were compared between groups. All of the groups had left caudate nucleus head volumes significantly higher than right, although there were no between-group differences. The results in relation to previous studies are discussed.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Núcleo Caudado/patologia , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Imageamento por Ressonância Magnética/estatística & dados numéricos , Criança , Dominância Cerebral/fisiologia , Feminino , Humanos , Inteligência/fisiologia , Masculino , Valores de Referência
17.
Med Sci Sports Exerc ; 34(2): 203-12, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11828226

RESUMO

PURPOSE: The effects of exercise on children with attention-deficit hyperactivity disorder (ADHD) were evaluated by studying the rate of spontaneous eye blinks, the acoustic startle eye blink response (ASER), and motor impersistence among 8- to 12-yr-old children (10 boys and 8 girls) meeting DSM-III-R criteria for ADHD. METHODS: Children ceased methylphenidate medication 24 h before and during each of three daily conditions separated by 24-48 h. After a maximal treadmill walking test to determine cardiorespiratory fitness (VO(2peak)), each child was randomly assigned to counterbalanced conditions of treadmill walking at an intensity of 65-75% VO(2peak) or quiet rest. Responses were compared with a group of control participants (11 boys and 14 girls) equated with the ADHD group on several key variables. RESULTS: Boys with ADHD had increased spontaneous blink rate, decreased ASER latency, and decreased motor impersistence after maximal exercise. Girls with ADHD had increased ASER amplitude and decreased ASER latency after submaximal exercise. CONCLUSIONS: The findings suggest an interaction between sex and exercise intensity that is not explained by physical fitness, activity history, or selected personality attributes. The clinical meaning of the eye blink results is not clear, as improvements in motor impersistence occurred only for boys after maximal exercise. Nonetheless, these preliminary findings are sufficiently positive to encourage additional study to determine whether a session of vigorous exercise has efficacy as a dopaminergic adjuvant in the management of behavioral features of ADHD.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Exercício Físico/fisiologia , Estimulação Acústica/métodos , Limiar Anaeróbio/fisiologia , Piscadela/fisiologia , Criança , Teste de Esforço , Feminino , Humanos , Masculino , Atividade Motora/fisiologia , Descanso/fisiologia , Fatores Sexuais
18.
J Int Neuropsychol Soc ; 8(1): 22-36, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11843072

RESUMO

The planum temporale is clearly involved in language processing, for it serves as the auditory association cortex. Research has consistently demonstrated that 60 to 70% of the population has leftward asymmetry of the planum temporale. Research has also suggested that dyslexic individuals tend to have either rightward asymmetry or symmetrical plana. Moreover, many studies have found a relationship between the presence of dyslexia and/or language impairment and deficits in the normal right ear advantage found in dichotic listening paradigms. In this context, this study examined the relationship between planum temporale asymmetry and ear preference in dichotic listening performance in children with Developmental Dyslexia and Attention-Deficit/Hyperactivity Disorder (ADHD). Subjects included 19 children with dyslexia (10 of whom had a comorbid diagnosis of ADHD), 23 children with ADHD, and 12 diagnosed normal control children. Dichotic listening data were not collected for 8 of the 12 normal control children and for 3 of the 23 ADHD children. Results revealed no significant difference between ADHD and dyslexic subjects in regard to ear advantage on the free recall dichotic listening task. In addition, although the directed dichotic listening tasks were not related to degree of planum asymmetry, as predicted, results indicated that subjects who consistently displayed an atypical left ear advantage tended to have larger right bank lengths than those who consistently displayed a typical right ear advantage. These findings support the notion that some individuals with dyslexia or language deficits tend to have a larger right planum temporale and that performance on dichotic listening tasks may reflect this relatively unusual pattern.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/etiologia , Testes com Listas de Dissílabos , Dominância Cerebral , Dislexia/etiologia , Lobo Temporal/anormalidades , Transtorno do Deficit de Atenção com Hiperatividade/patologia , Córtex Auditivo/anormalidades , Estudos de Casos e Controles , Pré-Escolar , Dislexia/patologia , Feminino , Lateralidade Funcional , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , Rememoração Mental
19.
Arch Clin Neuropsychol ; 17(6): 531-46, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14591854

RESUMO

The clock drawing test has been found to be sensitive to visual-spatial perception, graphomotor skills, verbal reasoning, and executive functioning in adult patient populations, as well as frontal lobe maturation in normal children. Our study is among the first to assess the use of clock drawing as a neuropsychological measure in the pediatric population. Participants included 41 children with attention-deficit/hyperactivity disorder (ADHD) and 41 normal controls, ages 6-12 years, matched for age, gender, and handedness. Conceptualization of time and construction of the clock face were assessed separately using a scoring system normed on school-age children in an earlier study. Children with Predominantly Inattentive Type were found to perform similarly to those with Combined Type of ADHD. However, children with ADHD, regardless of subtype, performed significantly poorer than controls. Qualitative analysis of performance revealed errors that were subsequent to poor planning during task execution, consistent with executive dysfunction commonly present in children with ADHD. Further, multiple regression analysis demonstrated that a neuropsychological measure of executive functioning was predictive of clock construction performance in children with ADHD. Constructional praxis and receptive vocabulary also were predictive of clock construction ability. Implications of these findings are discussed.

20.
Buenos Aires; Panamericana; 1987. 272 p. ilus. (104743).
Monografia em Espanhol | BINACIS | ID: bin-104743
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