Comparison of quantitative EEG between patients with Alzheimer's disease and those with Parkinson's disease dementia.

OBJECTIVE: Dementia frequently occurs in Parkinson's disease (PD) but its pathophysiological basis is little known. Comparative EEG studies of Alzheimer's disease (AD) and Parkinson's disease dementia (PDD) are still rare, but could provide knowledge on the different pathophysiological mechanisms involved. The objective of the present study was to comparatively evaluate the absolute power and coherence on the EEG for patients with AD and PDD. METHODS: This study assessed 38 adults with AD, 12 with PDD, 31 with Parkinson's disease without dementia, and 37 controls (CG) by a neurological evaluation, CERAD neuropsychological battery, executive functions tests and qEEG, calculating global absolute powers for the delta, theta, alpha and beta bands and inter- and intra-hemispheric coherences. RESULTS: The delta and theta powers were highest in PDD and lowest in CG (p<0.05). The beta frontal-occipital inter-hemispheric coherence was highest in PDD (p<0.05). Whereas, alpha and beta frontal inter-hemispheric coherence was highest in PDD and lowest in AD (p<0.05). CONCLUSION: These results suggest that qEEG power and coherence measures are different in AD and PDD. SIGNIFICANCE: These qEEG differences must be related to the distinct mechanisms of cortical neural connections in AD and PDD.

Electroencephalographic alpha reactivity on opening the eyes in children with attention-deficit hyperactivity disorder.

The quantification of differences in alpha electroencephalograph (EEG) activity between the eyes-closed and eyes-open resting conditions could be used as a measure of resting state arousal. The objective of this study was to evaluate the contribution of EEG alpha reactivity on opening the eyes, to the neurophysiology of children with attention-deficit hyperactivity disorder (ADHD). Thirty-eight children with ADHD were assessed using quantitative EEG (qEEG) analysis of absolute band power at rest, with eyes open and closed. Alpha reactivity index was calculated on opening the eyes, defined from the relationship between the absolute powers in the respective bands in the periods with the eyes open and closed. EEG data of 38 sex- and age-matched controls, with no neurological or psychiatric problems, were collected for comparison. There was a significant reduction in absolute alpha power at all electrodes for both ADHD and control groups with eyes open, indicating an increase in the arousal level. However, the alpha reactivity index was greater, corresponding to less reactivity, in the frontal regions of the children with ADHD (P < .01). Such a finding suggests alterations in arousal mechanisms in ADHD. This research suggests that alpha reactivity on opening the eyes, allied with other variables from the qEEG, may improve diagnostic accuracy in ADHD.

Alzheimer's disease: relationship between cognitive aspects and power and coherence EEG measures / Doença de Alzheimer: relação entre aspectos cognitivos e medidas de potência e coerência no eletrencefalograma

OBJECTIVE: To evaluate the relationship between specific cognitive aspects and quantitative EEG measures, in patients with mild or moderate Alzheimer's disease (AD). METHOD: Thirty-eight AD patients and 31 controls were assessed by CERAD neuropsychological battery (Consortium to Establish a Registry for AD) and the electroencephalogram (EEG). The absolute power and coherences EEG measures were calculated at rest. The correlations between the cognitive variables and the EEG were evaluated. RESULTS: In the AD group there were significant correlations between different coherence EEG measures and Mini-Mental State Examination, verbal fluency, modified Boston naming, word list memory with repetition, word list recall and recognition, and constructional praxis (p<0.01). These correlations were all negative for the delta and theta bands and positive for alpha and beta. There were no correlations between cognitive aspects and absolute EEG power. CONCLUSION: The coherence EEG measures reflect different forms in the relationship between regions related to various cognitive dysfunctions.

OBJETIVO: Avaliar as relações entre aspectos cognitivos específicos e medidas quantitativas do EEG em pacientes com doença de Alzheimer (DA) leve e moderado. MÉTODO: Trinta e oito pacientes com DA e 31 controles foram avaliados com a bateria neuropsicológica CERAD (Consortium to Establish a Registry for AD) e o eletroencefalograma. Foram realizadas medidas de potência absoluta e coerência do EEG, durante repouso, e avaliadas suas relações com variáveis do CERAD. RESULTADOS: No grupo DA houve correlações significativas entre diferentes medidas de coerência e o mini-exame do estado mental, fluência verbal, teste de nomeação de Boston modificado, memória de lista de palavras com repetição, recordação e reconhecimento de lista de palavras e praxia construtiva (p<0,01). Essas correlações foram negativas para as faixas delta e teta e positivas para alfa e beta. CONCLUSÃO: As medidas de coerência do EEG em repouso refletem diferentes formas de organização nas relações entre regiões, relacionadas a várias disfunções cognitivas.

EEG theta and alpha reactivity on opening the eyes in the diagnosis of Alzheimer's disease.

The objective of this study was to evaluate the contribution of EEG theta and alpha reactivity on opening the eyes, in the diagnosis of slight and moderate Alzheimer's disease (AD). Thirty four patients with AD and a control group of 30 individuals were studied, all being assessed using a neurological evaluation, CERAD neuropsychological battery (consortium to establish a registry for Alzheimer's disease), incorporating the Mini Mental State Examination (MMSE), Clinical Dementia Rating (CDR) and a qEEG analysis of the absolute band power at rest, with the eyes both open and closed. The theta and alpha reactivity indices were calculated on opening the eyes, defined from the relationship between the absolute powers in the respective bands in the periods with the eyes open and with them closed, the quotient of the relationship between the alpha and theta indices, the alpha/theta ratio, was also calculated. Multiple regression models were used to determine the accuracy in discriminating between the AD and control groups. A regression model using only cognitive data provided an accuracy of 92.2%, whereas a regression model combining cognitive data and qEEG measurements provided an accuracy of 95.3% in the classification between AD and the controls. The variable for the qEEG was the left hemisphere alpha/theta index, since the other parameters were shown to be inferior with respect to the clinical data in the regression analysis. The integrated study of the theta and alpha reactivity indices on opening the eyes and the alpha/theta index, was shown to be a useful approach in qEEG in the evaluation of AD and should be evaluated with larger samples and with other data analysis methods, with the aim of increasing the accuracy.

Alzheimer's disease: relationship between cognitive aspects and power and coherence EEG measures.

OBJECTIVE: To evaluate the relationship between specific cognitive aspects and quantitative EEG measures, in patients with mild or moderate Alzheimer's disease (AD). METHOD: Thirty-eight AD patients and 31 controls were assessed by CERAD neuropsychological battery (Consortium to Establish a Registry for AD) and the electroencephalogram (EEG). The absolute power and coherences EEG measures were calculated at rest. The correlations between the cognitive variables and the EEG were evaluated. RESULTS: In the AD group there were significant correlations between different coherence EEG measures and Mini-Mental State Examination, verbal fluency, modified Boston naming, word list memory with repetition, word list recall and recognition, and constructional praxis (p<0.01). These correlations were all negative for the delta and theta bands and positive for alpha and beta. There were no correlations between cognitive aspects and absolute EEG power. CONCLUSION: The coherence EEG measures reflect different forms in the relationship between regions related to various cognitive dysfunctions.

Benign childhood epilepsy with centro-temporal spikes: evolutive clinical, cognitive and EEG aspects.

Thirty-two children with benign childhood epilepsy with centrotemporal spikes (BECTS) were studied for a mean period of 27.6 months. The characteristics of the seizures, electroencephalogram (EEG), WISC-III and School Performance Test were compared at the start and end of the study. Nine (28.1%) children continued having seizures. Epileptiform activity (EA) on the EEG reduced in number and was no longer recorded in 6 (18.7%) children. There was a significant improvement in the performance and perceptual organization IQ values. The improvement in reading performance failed to reach statistical significance. The performance in arithmetic worsened in 43.7% of the children, and this was associated with the persistence of epileptic seizures. There were no significant correlations between changes in cognitive aspects and characteristics of EA. There is a need to continue this study, and also search for other factors influencing the evolution of cognitive abilities in children with BECTS.

Benign childhood epilepsy with centro-temporal spikes: evolutive clinical, cognitive and EEG aspects / Epilepsia benigna da infância com pontas centrotemporais: aspectos evolutivos clínicos, cognitivos e do EEG

Thirty-two children with benign childhood epilepsy with centrotemporal spikes (BECTS) were studied for a mean period of 27.6 months. The characteristics of the seizures, electroencephalogram (EEG), WISC-III and School Performance Test were compared at the start and end of the study. Nine (28.1 percent) children continued having seizures. Epileptiform activity (EA) on the EEG reduced in number and was no longer recorded in 6 (18.7 percent) children. There was a significant improvement in the performance and perceptual organization IQ values. The improvement in reading performance failed to reach statistical significance. The performance in arithmetic worsened in 43.7 percent of the children, and this was associated with the persistence of epileptic seizures. There were no significant correlations between changes in cognitive aspects and characteristics of EA. There is a need to continue this study, and also search for other factors influencing the evolution of cognitive abilities in children with BECTS.

Foram estudados aspectos evolutivos clínicos, cognitivos e eletrencefalográficos (EEG) de 32 crianças com epilepsia benigna da infância com pontas centrotemporais (EBICT) acompanhadas por 27,6 meses. Foram comparadas as características das crises, do EEG, do WISC-III e do Teste de Desempenho Escolar ao início e ao final do estudo. Nove (28,1 por cento) crianças continuaram apresentando crises. A atividade epileptiforme (AE) ao EEG reduziu-se em número e não mais foi registrada em 6 (18,7 por cento) crianças. Houve melhora significativa nos QI de execução e de organização perceptual. A melhora do desempenho em leitura não alcançou significância estatística, enquanto em 43,7 por cento das crianças houve piora em aritmética. Esta foi associada à persistência de crises epilépticas. Não houve correlações significativas entre aspectos cognitivos e características da AE. Há necessidade de estudar até a remissão total das crises e da AE, assim como procurar outros fatores que influenciem a evolução das habilidades cognitivas das crianças com EBICT.

Educational problems related to quantitative EEG changes in benign childhood epilepsy with centrotemporal spikes.

The relationship between educational problems and clinical/electroencephalographic aspects was assessed in 38 children with benign childhood epilepsy with centrotemporal spikes (BECTS). Children were assessed using the School Performance Test; questionnaires on learning difficulties administered to parents and teachers; the Wechsler Intelligence Scale for Children, Third Edition; and EEGs. Absolute and relative amplitudes in the classic bands (quantitative EEG) and characteristics of epileptiform activity on the EEG were examined. Educational problems were observed in 7 (18.4%) children with BECTS. In this subgroup, relative alpha amplitudes at the central and parietal electrodes were lower as compared with those of the BECTS subgroup with normal educational performance and a control group matched for age, gender, and socioeconomic status. The data indicated a possible relationship between alterations in background brain electrical activity and the tendency toward inferior educational performance in children with BECTS. This study suggested that quantitative EEGs are a possible physiological tool in the assessment of cognitive aspects in children with BECTS.

Epileptiform EEG discharges in benign childhood epilepsy with centrotemporal spikes: reactivity and transitory cognitive impairment.

The reactivity of rolandic spikes (RS) and the occurrence of transitory cognitive impairment (TCI) during RSs were assessed in 33 children with benign childhood epilepsy with centrotemporal spikes (BECTS). The children were assessed simultaneously with EEG and computerized neuropsychological testing in a visual discrimination between words and pseudowords task (DWPT). In 20 (60.6%) children, there were insufficient RS to assess the occurrence of TCI. Of 13 children with RS between stimulus presentation and response, only 2 (15.4%) made a significantly greater proportion of errors during RS than during RS-free periods, characterizing the occurrence of TCI. The RS appear to be easily inhibited by the DWPT. TCI occurred in a limited number of cases and did not impair school performance. There is a need to study other tasks and search for other factors influencing cognitive abilities in children with BECTS.

Event related potentials during the visual discrimination of words and pseudowords by children.

Event related potentials (ERPs) in reading were studied in children in a word and pseudoword discriminating task. Seventy-nine children (9 to 11 year old), all with no elements suggesting brain injury and with school performance compatible with their age were studied. The ERP were registered as there were presented, visually, successively and in a random manner, 100 words and 100 pseudowords. For each stimulus the child pressed a key corresponding to the discrimination between word and pseudoword. The register was carried out for the electrodes of the 10-20 system and the mean amplitudes and latency peaks measured and also the amplitude from 200 to 550 milliseconds. The most significant differences between the ERPs occurred in Cz, with greater negativity for the mean of the amplitude between 425 and 550 milliseconds for pseudowords (N400). The N400 was more precocious in 11 year old. The influence of age was thus evident and also the differences in ERPs between words and pseudowords.

Event related potentials during the visual discrimination of words and pseudowords by children / Potenciais evocados cognitivos na discriminação visual entre palavras e pseudopalavras em crianças

Event related potentials (ERPs) in reading were studied in children in a word and pseudoword discriminating task. Seventy-nine children (9 to 11 year old), all with no elements suggesting brain injury and with school performance compatible with their age were studied. The ERP were registered as there were presented, visually, successively and in a random manner, 100 words and 100 pseudowords. For each stimulus the child pressed a key corresponding to the discrimination between word and pseudoword. The register was carried out for the electrodes of the 10-20 system and the mean amplitudes and latency peaks measured and also the amplitude from 200 to 550 milliseconds. The most significant differences between the ERPs occurred in Cz, with greater negativity for the mean of the amplitude between 425 and 550 milliseconds for pseudowords (N400). The N400 was more precocious in 11 year old. The influence of age was thus evident and also the differences in ERPs between words and pseudowords.

Foram estudadas 79 crianças (9 a 11 anos) sem elementos sugestivos de comprometimento cerebral e com desempenho escolar compatível com a idade. Os PCL foram registrados enquanto eram apresentados, visualmente, sucessivamente e de modo aleatório, 100 palavras e 100 pseudopalavras. Para cada estímulo a criança acionava uma tecla correspondente à discriminação entre palavra e pseudopalavra. O registro foi realizado para os eletrodos do sistema 10-20 e foram feitas medidas de médias de amplitude e de latências de pico e de amplitude de 200 a 550 milissegundos. Em Cz ocorreram as diferenças mais significativas entre os PCL, com maior negatividade da média de amplitude entre 425 e 550 milissegundos para pseudopalavras (N400). O N400 foi mais precoce nas crianças com 11 anos. Evidenciou-se assim a influência da idade e as diferenças no PCL entre palavras e pseudopalavras.

Quantitative EEG in children with learning disabilities: analysis of band power.

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 carried out while awake and resting, and the values for absolute and relative powers calculated. The results were 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 children with learning disabilities between the relative power alpha 2 and the verbal, performance 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.

Benign childhood epilepsy with centro-temporal spikes: quantitative EEG and the Wechsler intelligence scale for children (WISC-III).

Benign childhood epilepsy with centro-temporal spikes (BECTS) is a form of focal idiopathic epilepsy, with seizure remission by the age of 18. Recent studies have suggested that some children with BECTS can suffer from deficits of memory, attention and learning ability and in auditory-verbal and performance sub-tests. On the other hand, alterations in the baseline brain electrical activity determined by using the quantitative electroencephalogram (qEEG) have been described. The objective of this study was to evaluate the absolute and relative powers in the delta, theta, alpha and beta bands of the qEEG in children with BECTS, and their relation to IQ measurements (WISC-III). Twenty-six 8 to 11-year-old children with BECTS were studied, paired with a control group of healthy children according to age and gender. It was shown that the absolute delta and theta powers were statistically greater in the children with BECTS than in the control group, at almost all the electrodes. In the children with BECTS, a negative correlation (Pearson's correlation test) was observed at various electrodes between the absolute delta and theta powers and the performance IQ. These data indicate a possible relationship between maturational disturbance in the brain electrical activity development and the tendency for inferior cognitive performance in children with BECTS.

Quantitative EEG in children with learning disabilities: analysis of band power

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 potências 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 relação ao grupo controle. Nas crianças com dificuldade de aprendizagem houve correlação elevada e positiva entre 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.

[Quantitative electroencephalography in children with benign childhood epilepsy with centrotemporal spikes: analysis of band power]. / Eletrencefalograma quatitativo em crianças com epilepsia benigna da infância com pontas centrotemporais: análise de freqüências.

Quantitative EEG aspects are studied in children with benign childhood epilepsy with centrotempral spikes (BCET). A total of 27 children, from 7 to 11 years neurologically and intellectually normal was studied and compared to a control group of normal children. They were submitted to anamnesis, neurological examination, Raven test, digital electroencephalogram and quantitative eletroencephalogram analysis. There was a higher delta, theta, alpha and beta absolute power in most of the electrodes and of alpha and beta for some electrodes in the BCET group. Relative theta power was also higher for the BECT group in most of the electrodes. These findings suggest that in BECT there are diffuse differences form age-matched normal children including a difference in relative spectrum of electrical cerebral activity and that this may be related to a functional immaturity.

Eletrencefalograma quatitativo em crianças com epilepsia benigna da infância com pontas centrotemporais: análise de freqüências / Quantitative electroencephalography in children with bening childhood epilepsy with centrotemporal spikes: analysis of band power

Abordaram-se parâmetros quantitativos do eletrencefalograma em crianças com epilepsia benigna da infância com pontas centrotemporais (EBICT). Foram estudadas 27 crianças com diagnósticos de EBICT. Foi realizado o eletrecenfalograma durante vigília, em repouso, e selecionadas cerca de 20 janelas com 2,56 s. Foram calculados os valores de potência absoluta e relativa nas faixas delta, teta, alfa e beta. Os resultados foram comparados aos de 27 crianças sadias pareadas quanto a idade e escolaridade materna. A potência absoluta foi significativamente maior no grupo EBICT nas nas bandas delta e teta para a quase totalidade dos eletrodos e para alguns eletrodos nas faixas alfa e beta. A potência relativa teta foi também maior no grupo EBICT na maioria dos eletrodos. Esses achados sugerem que na EBICT, embora a atividade epileptiforme seja focal. Ocorrem modificações funcionais difusas que incluem alterações do perfil da distribuição das faixas de frequência, com maior potência relativa teta.

Eplepsia benigna da infância com pontas centrotemporais: foco central alto ou baixo / Benign childhood epilepsy with centrotemporal spikes: high and low central focus

Foram selecionadas 20 crianças com diagnóstico de epilepsia benigna da infância com pontas centrotemporais. Realizou-se anamnese, exame neurológico, aplicação da Escala de Maturidade Mental'' Columbia'' (1993) e eletrencefalograma digital. (EEG) O EEG digital foi gravado com eletrodos de acordo com o sistema internacional 10-20, acrescido de um eletrodo suplementar entre o eletrodos C3 eT3 ou C4 e T4 no lado onde ocorreu o maior número de pontas. Foi realizada a promediação dessas descargas para análise do local de máxima negatividade. A ocorrência de crises envolvendo um membro superior foi proporcionalmente maior nos sujeitos com pontas de máxima negatividade em C3, C4 do que em C5, C6, T3 ou T4. A atividade epileptiforme não centrotemporal associada foi mais frequente nos sujeitos com descargas centrotemporais de máxima negatividade em C3 e C4. Esse estudo demonstra a existência de diferenças clínicas e eletrencefalográficas de acordo com a localização das descargas centrotemporais

[Somatosensory evoked spikes and epileptiform activity in "normal" children]. / Pontas evocadas por estímulos somatossensitivos e atividade epileptiforme no eletrencefalograma em crianças "normais"

Little is known about somatosensory evoked spikes (SES) in the EEG of normal children. We studied the occurrence of SES and spontaneous epileptiform activity (SEA) in 173 normal children ageg 7 to 11 years. During the EEG ten taps were applied to both hands and feet. The occurrence of high voltage potentials evoked by each stimulation of one or both heels or hands (SES) and the occurrence of SEA were evaluated. SEA was observed in four children (2.3 %): central/parietal spikes in two cases, generalized spike-and-wave in one, and parietal/midtemporal spikes in one case. A ten years old girl (0,58%) had SES on median parietal region by tapping the left foot. This EEG was otherwise normal. Our findings of SEA are similar to those obtained in other normal populations. SES can be observed in normal children. These SES suggest that we are dealing with an age-related functional phenomenon.

[Quantitative electroencephalography in healthy school-age children: analysis of band power]. / Eletrencefalograma quantitativo em escolares sadios: an lise de frequências.

Quantitative EEG aspects are studied with respect to age, sex and sociocultural parameters. A total of 162 children, from 7 to 11 years, neurologically and intellectually normal was studied. They were submitted to anamnesis, neurological examination, Raven test, school performance test, digital electroencephalogram and quantitative electroencephalogram analysis. There was a decrease in absolute and relative delta and theta power and an increase in alpha 2 relative power with the increase of age. These findings are similar to those observed in studies from Europe, Asia and North America. Absolute delta and alpha power were higher in children with better scores in school performance test. There were no significant differences in quantitative electroencephalographic parameters according to sex and the mother's educational level.

Pontas evocadas por estímulos somatossensitivos e atividade epileptiforme no eletrencefalograma em crianças "normais" / Somatosensory evoked spikes and epileptiform activity in \"normal\" children

Estudamos a ocorrência de potenciais de alta voltagem evocados por estímulos somatossensitivos - pontas evocadas (PE) - e de atividade epileptiforme espontânea (AE) no EEG de 173 crianças normais de 7 a 11 anos de idade. Durante o EEG, dez percussöes foram realizadas nas mäos e pés. Foi avaliada a ocorrência de PE acompanhando cada um dos estímulos e a presença de AE. AE foi observada em quatro crianças (2,3 por cento): pontas centroparietais em duas, complexos de ponta-onda lenta generalizados em uma e pontas parietais e temporais médias em uma. Uma menina de 10 anos de idade (0,58 por cento) teve ao EEG pontas parietais medianas evocadas pela percussäo do pé esquerdo. Este EEG era normal quanto a outros aspectos. Nossos achados de AE em crianças normais säo similares aos encontrados em estudos de outros países. Constatamos que espículas somatossensitivas podem ser observadas em crianças normais o que sugere uma natureza funcional ligada à idade