Automatic Classification of Subjects of the PSEN1-E280A Family at Risk of Developing Alzheimer's Disease Using Machine Learning and Resting State Electroencephalography.

BACKGROUND: The study of genetic variant carriers provides an opportunity to identify neurophysiological changes in preclinical stages. Electroencephalography (EEG) is a low-cost and minimally invasive technique which, together with machine learning, provide the possibility to construct systems that classify subjects that might develop Alzheimer's disease (AD). OBJECTIVE: The aim of this paper is to evaluate the capacity of the machine learning techniques to classify healthy Non-Carriers (NonCr) from Asymptomatic Carriers (ACr) of PSEN1-E280A variant for autosomal dominant Alzheimer's disease (ADAD), using spectral features from EEG channels and brain-related independent components (ICs) obtained using independent component analysis (ICA). METHODS: EEG was recorded in 27 ACr and 33 NonCr. Statistical significance analysis was applied to spectral information from channels and group ICA (gICA), standardized low-resolution tomography (sLORETA) analysis was applied over the IC as well. Strategies for feature selection and classification like Chi-square, mutual informationm and support vector machines (SVM) were evaluated over the dataset. RESULTS: A test accuracy up to 83% was obtained by implementing a SVM with spectral features derived from gICA. The main findings are related to theta and beta rhythms, generated in the parietal and occipital regions, like the precuneus and superior parietal lobule. CONCLUSION: Promising models for classification of preclinical AD due to PSEN-1-E280A variant can be trained using spectral features, and the importance of the beta band and precuneus region is highlighted in asymptomatic stages, opening up the possibility of its use as a screening methodology.

Perfil clínico y cognitivo de la atrofia cortical posterior y sus diferencias con la enfermedad de Alzheimer esporádica tardía y familiar precoz / Clinical and cognitive profile of posterior cortical atrophy and its differences with late sporadic and early familial Alzheimer's disease

Introducción. La atrofia cortical posterior (ACP) es una demencia focal que se manifiesta al inicio con trastornos cognitivos posteriores, principalmente alteración visuoperceptual por el daño en la corteza occipitoparietal, lo que permite en la clínica diferenciarla de la enfermedad de Alzheimer (EA). Objetivos. Analizar y comparar el rendimiento cognitivo de pacientes con ACP y con EA. Materiales y métodos. La muestra estuvo formada por los siguientes grupos: cuatro pacientes con ACP, siete con EA familiar precoz, nueve con EA esporádica tardía y cuatro controles sanos. A cada participante se le aplicó un protocolo de evaluación neuropsicológica para valorar procesos cognitivos y funcionalidad. La comparación entre grupos se realizó utilizando la prueba no paramétrica U de Mann-Whitney. Resultados. Los pacientes con ACP obtuvieron puntuaciones significativamente inferiores en praxias constructivas e ideacionales, lectura, cálculo y visuopercepción, respecto a ambos grupos de EA. Por el contrario, en memoria verbal, fluidez semántica y función ejecutiva, el grupo con ACP presentó mejor desempeño. Conclusión. Al inicio del proceso neurodegenerativo la clínica de la ACP se diferencia de la de EA. La ACP es una demencia con características sintomatológicas propias y no sólo una variante de la EA, aunque ambas compartan el mismo sustrato histopatológico.

Introduction. Posterior cortical atrophy (PCA) is a focal dementia manifested by posterior cognitive disorders, initially visuoperceptual alterations due to damage in occipito-parietal cortex, which permits PCA to be clinicallydifferentiated of Alzheimer's Disease (AD). Objetive. To analize and to compare cognitive performance of patients with PCA and with AD. Materials and methods. Sample was conformed by the following groups: four patients with PCA, seven with early familial AD, nine with late sporadic AD and four healthy controls. A neuropsychological examination battery was administrated to each participant in order to assess cognitive processes and functionality. Between-groups comparisons were made by using U Mann-Whitney non parametric test.Results. Patients with PCA had significantly lower scores in constructional and ideational praxias, reading, calculation andvisuoperception, compared to both AD groups. In contrast, PCA group showed better performance in verbal memory,semantic fluency and executive function.Conclusion. At the beginning of neurodegenerative process, PCA symptomatology is clearly different of that presented in AD. PCA is a dementia with particular symptomatic characteristics and not only a variant of AD, even if both share the same hystopathological substrate.

Consumo de energía y nutrientes en un grupo de pacientes con demencia tipo Alzheimer (DTA) / Energy and Nutrients consumption in patients with Alzheimer's disease (AD)

El consumo de energía y nutrientes en los pacientes con demencia tipo Alzheimer (DTA) puede estar comprometido por los cambios fisiológicos, socioeconómicos y psicológicos relacionados con la enfermedad, además de los procesos propios del envejecimiento. Objetivo: Evaluar el consumo de energía y nutrientes en un grupo de pacientes con DTA del grupo Neurociencias de la Universidad de Antioquia según el estadío de evolución de la enfermedad. Metodología: Estudio descriptivo transversal. Para obtener la información del consumo de energía y nutrientes se realizó un recordatorio de 24 horas en tres días diferentes, incluyendo un día de fin de semana. Resultados: 68 pacientes evaluados, con edad promedio de 65.5 ± 12.8 años; el estadío más frecuente fue el moderado. La ingesta de energía y nutrientes mostró que no hay diferencias significativas en el consumo de los nutrientes por estadio de la enfermedad; el consumo de energía se encontró más comprometido en el estadio moderado; el consumo de proteínas fue adecuado en el severo y en exceso en los estadios leve y moderado. De los micronutrientes, se encontró un con-sumo probablemente inadecuado para el calcio, el magnesio, la vitamina B6 y el ácido fólico. Conclusión: es necesario implementar una atención nutricional oportuna y continua a los pacientes con DTA, brindar educación nutricional a las familias en aspectos relacionados con el cuidado nutricional e individualizar la atención de cada paciente.

The energy and nutrients consumptionin patients with Alzheimer’sdisease (AD) are compromised byphysiological, socioeconomic andpsychological changes related to thedisease, in addition to aging process.Objective: To evaluate energy andnutrients consumption in a groupof patients with AD, that wererecruited from the NeuroscienceGroup of the University of Antioquia-Medellin. It was done according todisease stage. Methods: It is a cross-sectional descriptive study. To obtain the data of food consumption, a 24 hoursrecall questionnaire was applied inthree different days, in addition oneday during weekend. Results: 68 patients were evaluated, with average age of 65.5 ± 12.8 years; the most frequent disease stage found was moderate. There were no significant differences in the consumption of the nutrients and energy according to disease stage; energy consumption was more altered in moderate stage; theprotein consumption was adequatein severe, and excessive in mild andmoderate stages. For micronutrientssuch as calcium, magnesium, B6 vitamin and folic acid, intake were assumed to be insufficient. Conclusion: it is indispensable to implement an opportune and continuousnutritional care for patientssuffering AD, moreover nutritionaleducation for their families in issuesrelated to nutritional attention isnecessary.