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The objective of this study was to evaluate relationships between quantitative EEG (qEEG) changes and cognitive disturbance (mild cognitive impairment or dementia) and the motor disturbance stage in Parkinson's disease (PD). Thirty-two PD patients (age = 67.2 +/- 10.0) and 26 normal subjects (age = 68.4 +/- 4.7) were assessed using a neurological evaluation, modified Hoehn and Yahr (HY) scale for PD, a Portuguese version of the CERAD neuropsychological battery (consortium to establish a registry for Alzheimer's disease) incorporating the Mini-mental Status Examination, Clinical Dementia Rating and an EEG analysis of absolute and relative band amplitude at rest. Four groups were compared: three with PD (7 patients with dementia, 10 with mild cognitive impairment and 15 with no cognitive disturbances) and the control group. The qEEG showed no significant differences between the control group and PD patients without cognitive disturbance. Abnormalities on the qEEG were essentially associated with the occurrence of mild cognitive impairment or dementia in patients with PD. There was an increase in the absolute and relative posterior theta amplitude in the groups with mild cognitive impairment or dementia and of the posterior absolute and relative delta amplitude in the group with dementia This study suggested qEEG as a possible physiological tool in the assessment of cognitive aspects in PD.

-In order to better understand the mechanisms of learning disabilities it is important to evaluate the electroencephalogram parameters and their relation to the results of the Wechsler Intelligence Scale. Thirty-six children with complaints of learning disability were studied. Electroencephalograms were c a rried out while awake and resting, and the values for absolute and relative powers calculated. The re s u l t s w e re compared with those of 36 healthy children paired with respect to age, gender and maternal scholastic level. In the group with learning disabilities, the absolute (in the delta, theta and alpha 1 bands) and relative (theta) power values were higher and the relative power alpha 2 value significantly lower at the majority of the electrodes in relation to the control group. There was a high positive correlation in the c h i l d ren with learning disabilities between the relative power alpha 2 and the verbal, perf o rmance and total IQ values. These quantitative electroencephalogram findings in children with learning disabilities have a clear relation with psychological measurements and could be due to brain immaturity.KEY WORDS: quantitative EEG, EEG maturation, frequency analysis, cognition, intelligence quotient.E l e t rencefalograma quantitativo em crianças com dificuldades de aprendizagem: análise de freqüências RESUMO -Para compreender melhor os mecanismos das dificuldades de aprendizagem é importante avaliar a relação entre parâmetros do eletrencefalograma e resultados da Escala Weschler de Inteligência. Foram estudadas 36 crianças com queixas de dificuldades de aprendizagem. Foi realizado o eletrencefalograma durante vigília, em repouso e calculados os valores de potência absoluta e relativa. Os resultados foram comparados aos de 36 crianças sadias pareadas quanto a idade, gênero e escolaridade materna. As potên-cias absoluta (das faixas delta, teta e alfa 1) e relativa (teta) foram maiores e a potência relativa alfa 2 foi significativamente menor, na maioria dos eletrodos, no grupo com dificuldade de aprendizagem em re l a ç ã o ao grupo controle. Nas crianças com dificuldade de aprendizagem houve correlação elevada e positiva e n t re a potência relativa alfa 2 e o QI. Os achados do eletrencefalograma quantitativo das crianças com dificuldade aprendizagem têm nítida relação com medidas psicológicas e podem ser decorrentes de imaturidade cerebral.

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-There is much controversy about the importance of the electroencephalogram (EEG) in assessing the attention-deficit/hyperactivity disorder (ADHD). The objective of this study was to assess the use of EEG and quantitative EEG (qEEG) in ADHD children. Thirty ADHD children and 30 sex-and age-matched controls with no neurological or psychiatric problems were studied. The EEG was recorded from 15 electrode sites during an eyes-closed resting condition. Epileptiform activity was assessed, as were the absolute and relative powers in the classical bands after application of the Fast Fourier transform. Epileptiform activity was found in 3 (10%) ADHD children. As compared to the controls, the ADHD group showed significantly greater absolute delta and theta powers in a diffuse way, and also greater absolute beta power and smaller relative alpha 1 and beta powers at some electrodes. A logistic multiple regression model, allowed for 83.3% sensibility and specificity in diagnosing ADHD.KEy worDs: attention-deficit/hyperactivity disorder, EEG, children. Atividade epileptiforme e eletrencefalograma quantitativo em crianças com transtorno de déficit de atenção/hiperatividadeResumo -Há controvérsias sobre a importância do eletrencefalogama (EEG) na avaliação do transtorno de déficit de atenção/hiperatividade (TDAH). o objetivo deste estudo foi avaliar, em crianças com TDAH, o EEG digital e quantitativo. Foram estudadas 30 crianças com TDAH e 30 sadias, sem evidências de problemas neurológicos ou psiquiátricos e pareadas por idade e gênero. Foi registrado o EEG em 15 posições de eletrodos, durante repouso e olhos fechados. Foi realizada pesquisa de atividade epileptiforme e feita análise de freqüências nas faixas clássicas, após aplicação da transformada rápida de Fourier. Foi encontrada atividade epileptiforme em 3 (10%) crianças com TDAH. o grupo TDAH teve, em relação ao grupo controle, significativamente, maior potência absoluta delta e teta, de modo difuso, assim como maior potência absoluta beta e menor potência relativa alfa 1 e beta, em alguns eletrodos. Um modelo de regressão múltipla logística possibilitou sensibilidade e especificidade de 83,3% no diagnóstico de TDAH.PAlAvrAs-cHAvE: transtorno de déficit de atenção/hiperatividade, EEG, infância. The attention-deficit/hyperactivity disorder (ADHD) is one of the commonest behavioral disorders in childhood. Due to advancing knowledge with respect to the prevalence, natural history, genetics, biology and treatment of ADHD, a greater number of patients are now receiving adequate treatment. The diagnosis of ADHD is based on the DsM Iv 1 criteria of which the essential characteristic consists of a persistent pattern of lack of attention and/ or hyperactivity-impulsivity more frequent and serious than that typically observed in individuals with an equivalent developmental level. some symptoms of hyperactivity and impulsivity should be present up to 7 years of age. some compromise due to the symptoms should be present in at least two contexts (e.g. at home or at school ...