Quantitative electroencephalography power and coherence measurements in the diagnosis of mild and moderate Alzheimer's disease

Abstract

Objective: To evaluate the contribution of quantitative electroencephalographic (qEEG) analyses in the diagnosis of Alzheimer's disease (AD). Method: Thirty-five patients from the Neurology Outpatients Clinic of PUC-Campinas, diagnosed with AD according to the NINCDS/ADRDA were evaluated, and compared with a control group consisting of 30 individuals with no cognitive deficit. The procedures consisted of clinical-neurological, cognitive and behavioral analyses and the qEEG (absolute power and coherence). Results: The AD group presented greater absolute power values in the delta and theta bands, greater theta/alpha indices and less frontal alpha and beta coherence. Logistic multiple regression models were constructed and those only showing variations in the qEEG (frontal alpha coherence and left frontal absolute theta power) showed an accuracy classification (72.3%) below that obtained in the mini-mental state examination (93%). Conclusion: The study of coherence and power in the qEEG showed a relatively limited accuracy with respect to its application in routine clinical practice. Key words: dementia, Alzheimer's disease, electroencephalography, EEG, coherence.Medidas de coerência e de potência absoluta no eletrencefalograma quantitativo no diagnóstico da doença de Alzheimer RESUMO Objetivo: Avaliar a contribuição das análises quantitativas do eletroencefalograma (qEEG) no diagnóstico da doença de Alzheimer (DA). Método: Foram avaliados 35 pacientes do ambulatório de Neurologia Clínica da PUC-Campinas, com o diagnóstico de DA segundo o NINCDS/ADRDA e comparados a 30 indivíduos, sem déficit cognitivo, de grupo controle. Os procedimentos foram avaliação clínico-neurológica, cognitiva e comportamental e EEGq (potência absoluta e coerência). Resultados: O grupo DA apresentou maiores potências absolutas nas faixas delta e teta, maiores índices teta/alfa e menor coerência alfa e beta frontal. Foram construídos modelos de regressão múltipla logística e aquele que contou apenas com variáveis do EEGq (coerência alfa frontal e potência absoluta teta frontal esquerda) teve acurácia de classificação (72,3%), inferior à obtida com o mini-exame do estado mental (93%). Conclusão: O estudo de coerência e potência no qEEG tem acurácia relativamente limitada no sentido de aplicação prática clínica rotineira. Palavras-chave: demência, doença de Alzheimer, eletroencefalografia, EEG, coerência, potência absoluta.

The relationship between the diagnosis method of neuronal dysfunction (DIMENSION) and brain pathology in the early stages of Alzheimer's disease

“…The ability of previous EEG methods, such as spectral power and coherence measures, to accurately detect very early‐stage AD and its progression was problematic, as the results were often difficult to interpret; it was not clear whether EEG corresponded to changes in processes within the brain. By comparing results from SPECT analysis and CSF markers in early‐stage AD, the present study investigated whether DIMENSION analysis reflects changes in brain processes related to AD.…”

Differences between encoding and retrieval failure in mild cognitive impairment: results from quantitative electroencephalography and magnetic resonance volumetry

“…ROIs with remaining all other 67 ROIs. We have estimated the functional connectivity at eight frequency bands (delta[1][2][3][4], theta[4][5][6][7][8], alpha1[8][9][10], alpha2[10][11][12], beta1[12][13][14][15], beta2[15][16][17][18][19][20], beta3[20][21][22][23][24][25][26][27][28][29][30], and gamma[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45].2.3 ...…”

Quantitative electroencephalography power and coherence measurements in the diagnosis of mild and moderate Alzheimer's disease

“…Dear Editors, We are grateful to Golimstok et al 1 for their interest in our work 2 , as also for the comments and questions they raised.…”