[Spectral analysis of the electroencephalogram in subjects with mild cognitive impairment]. / Análisis espectral del electroencefalogramaen sujetos con deterioro cognitivo leve.

INTRODUCTION: Mild cognitive impairment (MCI) is defined as a state of the ageing brain midway between normal cognition and dementia. Special attention has been paid to the electrophysiological substrate underlying Alzheimer's disease and MCI in order to identify as early as possible which subjects with MCI progress towards Alzheimer, which could be crucial for starting rehabilitation or pharmacological therapies. AIM: To perform a spectral characterisation of the electroencephalogram in subjects with MCI. PATIENTS AND METHODS: An electroencephalogram was carried out on 41 subjects with MCI in order to analyse the spectral measurements; apolipoprotein E genotype was also performed. RESULTS: In all, 94.8% of the sample displayed a significant increase in energy, and in 66.6% of them this was observed in the theta and delta bands, or both. Significant differences were found in the spectral measurements between carriers and non-carriers of the apolipoprotein E epsilon4 allele in the theta and alpha bands; there was also a statistically significant association between the years of schooling and being a carrier of this allele or not. An increase in the theta-alpha bands was observed in the left temporal region in subjects with a below-average number of years of schooling and carriers of the epsilon4 allele. CONCLUSIONS: In subjects with MCI and carriers of the epsilon4 allele, the alpha and theta cortical rhythms can be affected by similar pathological mechanisms and may be expressed earlier in subjects who have a lower level of schooling.

Análisis espectral del electroencefalograma en sujetos con deterioro cognitivo leve / Spectral analysis of the electroencephalogram in subjects with mild cognitive impairment

El deterioro cognitivo leve (DCL) se define como un estado del cerebro envejecido intermedio entrela cognición normal y la demencia; se ha prestado una especial atención al sustrato electrofisiológico de la enfermedad de Alzheimer y el DCL con la finalidad de identificar lo antes posible qué sujetos con DCL progresan a Alzheimer, lo cual podríaser crucial para el inicio de terapias de rehabilitación o farmacológicas. Objetivo. Caracterización espectral del electroencefalograma en sujetos con DCL. Pacientes y métodos. Se estudió a 41 sujetos con DCL a los cuales se les realizó electroencefalograma para el análisis de las medidas espectrales; además se realizó genotipo de apolipoproteína E. Resultados. El 94,8% de la muestra reveló un incremento significativo de energía; en el 66,6% de ellos se observó en las bandas theta y delta,o ambas. Se encontraron diferencias significativas en las medidas espectrales entre portadores y no portadores del alelo epsilon4 de la apolipoproteína E en las bandas theta y alfa, y además existió una asociación estadísticamente significativa entre los años de escolaridad y ser portador o no de dicho alelo. Se observó un incremento en las bandas theta-alfa en la región temporal izquierda en los sujetos por debajo de la media de años de escolaridad y portadores del alelo epsilon4. Conclusiones. En los sujetos con DCL y portadores del alelo epsilon4, los ritmos corticales alfa y theta pueden verse afectados por mecanismospatológicos similares, y puede expresarse de forma más precoz en los sujetos que presentan un nivel de escolaridad bajo

Mild cognitive impairment (MCI) is defined as a state of the ageing brain midway between normalcognition and dementia. Special attention has been paid to the electrophysiological substrate underlying Alzheimer’s disease and MCI in order to identify as early as possible which subjects with MCI progress towards Alzheimer, which could be crucial forstarting rehabilitation or pharmacological therapies. Aim. To perform a spectral characterisation of the electroencephalogram in subjects with MCI. Patients and methods. An electroencephalogram was carried out on 41 subjects with MCI in order to analyse the spectral measurements; apolipoprotein E genotype was also performed. Results. In all, 94.8% of the sampledisplayed a significant increase in energy, and in 66.6% of them this was observed in the theta and delta bands, or both. Significant differences were found in the spectral measurements between carriers and non-carriers of the apolipoprotein E epsilon4 allele in the theta and alpha bands; there was also a statistically significant association between the years of schoolingand being a carrier of this allele or not. An increase in the theta-alpha bands was observed in the left temporal region in subjects with a below-average number of years of schooling and carriers of the epsilon4 allele. Conclusions. In subjects withMCI and carriers of the epsilon4 allele, the alpha and theta cortical rhythms can be affected by similar pathological mechanisms and may be expressed earlier in subjects who have a lower level of schooling