The development and validation of a digital biomarker for remote assessment of Alzheimer's diseases risk.

Background: Digital cognitive assessment is becoming increasingly widespread in ageing research and care, especially since the COVID-19 pandemic. Remote online collection provides opportunities for ageing and dementia professionals to collect larger datasets, increase the diversity of research participants and patients and offer cost-effective screening and monitoring methods for clinical practice and trials. However, the reliability of self-administered at-home tests compared to their lab-based counterparts often goes unexamined, compromising the validity of adopting such measures. Objective: Our aim is to validate a self-administered web-based version of the visual short-term memory binding task (VSTMBT), a potential digital biomarker sensitive to Alzheimer's disease processes, suitable for use on personal devices. Methods: A final cross-sectional sample of 37 older-adult (51-77 years) participants without dementia completed our novel self-administered version of the VSTMBT, both at home on a personal device and in the lab, under researcher-controlled conditions. Results: ANOVA and Bayesian t-test found no significant differences between the task when it was remotely self-administered by participants at home compared to when it was taken under controlled lab conditions. Conclusions: These results indicate the VSTMBT can provide reliable data when self-administered at-home using an online version of the task and on a personal device. This finding has important implications for remote screening and monitoring practices of older adults, as well as supporting clinical practices serving diverse patient communities. Future work will assess remote administration in older adults with cognitive impairment and diverse socio-economic and ethno-cultural backgrounds as well as a bench-to-bedside application.

Measures of resting state EEG rhythms for clinical trials in Alzheimer's disease: Recommendations of an expert panel.

The Electrophysiology Professional Interest Area (EPIA) and Global Brain Consortium endorsed recommendations on candidate electroencephalography (EEG) measures for Alzheimer's disease (AD) clinical trials. The Panel reviewed the field literature. As most consistent findings, AD patients with mild cognitive impairment and dementia showed abnormalities in peak frequency, power, and "interrelatedness" at posterior alpha (8-12 Hz) and widespread delta (< 4 Hz) and theta (4-8 Hz) rhythms in relation to disease progression and interventions. The following consensus statements were subscribed: (1) Standardization of instructions to patients, resting state EEG (rsEEG) recording methods, and selection of artifact-free rsEEG periods are needed; (2) power density and "interrelatedness" rsEEG measures (e.g., directed transfer function, phase lag index, linear lagged connectivity, etc.) at delta, theta, and alpha frequency bands may be use for stratification of AD patients and monitoring of disease progression and intervention; and (3) international multisectoral initiatives are mandatory for regulatory purposes.

Structural neuroimaging differentiates vulnerability from disease manifestation in colombian families with Huntington's disease.

INTRODUCTION: The volume of the striatal structures has been associated with disease progression in individuals with Huntington's disease (HD) from North America, Europe, and Australia. However, it is not known whether the gray matter (GM) volume in the striatum is also sensitive in differentiating vulnerability from disease manifestation in HD families from a South-American region known to have high incidence of the disease. In addition, the association of enlarged brain perivascular spaces (PVS) with cognitive, behavioral, and motor symptoms of HD is unknown. MATERIALS AND METHODS: We have analyzed neuroimaging indicators of global atrophy, PVS burden, and GM tissue volume in the basal ganglia and thalami, in relation to behavioral, motor, and cognitive scores, in 15 HD patients with overt disease manifestation and 14 first-degree relatives not genetically tested, which represent a vulnerable group, from the region of Magdalena, Colombia. RESULTS: Poor fluid intelligence as per the Raven's Standard Progressive Matrices was associated with global brain atrophy (p = 0.002) and PVS burden (p ≤ 0.02) in HD patients, where the GM volume in all subcortical structures, with the exception of the right globus pallidus, was associated with motor or cognitive scores. Only the GM volume in the right putamen was associated with envy and MOCA scores (p = 0.008 and 0.015 respectively) in first-degree relatives. CONCLUSION: Striatal GM volume, global brain atrophy and PVS burden may serve as differential indicators of disease manifestation in HD. The Raven's Standard Progressive Matrices could be a cognitive test worth to consider in the differentiation of vulnerability versus overt disease in HD.

Development of Android apps for cognitive assessment of dementia and delirium.

The next generation of medical technology applications for hand-held portable platforms will provide a core change in performance and sophistication, transforming the way health care professionals interact with patients. This advance is particularly apparent in the delivery of cognitive patient assessments, where smartphones and tablet computers are being used to assess complex neurological conditions to provide objective, accurate and reproducible test results. This paper reports on two such applications (apps) that have been developed to assist healthcare professionals with the detection and diagnosis of dementia and delirium.

Promising developments in neuropsychological approaches for the detection of preclinical Alzheimer's disease: a selective review.

Recently published guidelines suggest that the most opportune time to treat individuals with Alzheimer's disease is during the preclinical phase of the disease. This is a phase when individuals are defined as clinically normal but exhibit evidence of amyloidosis, neurodegeneration and subtle cognitive/behavioral decline. While our standard cognitive tests are useful for detecting cognitive decline at the stage of mild cognitive impairment, they were not designed for detecting the subtle cognitive variations associated with this biomarker stage of preclinical Alzheimer's disease. However, neuropsychologists are attempting to meet this challenge by designing newer cognitive measures and questionnaires derived from translational efforts in neuroimaging, cognitive neuroscience and clinical/experimental neuropsychology. This review is a selective summary of several novel, potentially promising, approaches that are being explored for detecting early cognitive evidence of preclinical Alzheimer's disease in presymptomatic individuals.

Predicting outcome in mild cognitive impairment: 4-year follow-up study.

BACKGROUND: Cognitive impairment precedes the diagnosis of Alzheimer's disease. It is unclear which psychometric measures predict dementia, and what cut-off points should be used. Replicable cognitive measures to provide information about differential diagnosis and prognosis would be clinically useful. AIMS: In a prospective cohort study we investigated which measures distinguish between individuals with amnestic mild cognitive impairment (aMCI) that converts to dementia and those whose impairment does not, and which combination of measures best predicts the fate of people with aMCI. METHOD: Forty-four participants with aMCI underwent extensive neuropsychological assessment at baseline and annually thereafter for an average of 4 years. Differences in baseline cognitive performance of participants who were converters and non-converters to clinically diagnosed dementia were analysed. Classification accuracy was estimated by sensitivity, specificity, positive and negative predictive values and using logistic regression. RESULTS: Forty-one percent of participants had progressed to dementia by the end of study, with a mean annual conversion rate of 11%. Most (63%) showed persisting or progressive cognitive impairment, irrespective of diagnosis. The Addenbrooke's Cognitive Examination together with the discrimination index of the Hopkins Verbal Learning Test - Revised (but none of the demographic indices) differentiated the participants who were converters from the non-converters at baseline with 74% accuracy. CONCLUSIONS: Targeted neuropsychological assessment, beyond simple cognitive screening, could be used in clinical practice to provide individuals with aMCI with prognostic information and aid selective early initiation of monitoring and treatment among those who progress towards a clinically diagnosable dementia.

Prevalencia de las demencias en el municipio de Neiva 2003-2005 / Dementia prevalence in Neiva (Colombia) 2003-2005

Introducción. El aumento de la población de la tercera edad en el mundo y la consecuente proliferación de enfermedades de aparición tardía en especial los diferentes tipos de demencia, crean una necesidad de atención que obliga a los investigadores a realizar estudios epidemiológicos en los diferentes contextos para proporcionar a los organismos gubernamentales y de salud las herramientas que permitan planificar los recursos y los medios de atención a quienes ya ofrecieron al país una vida de trabajo. Objetivos. Describir y cuantificar las características sociodemográficas y clínicas de los adultos mayores de 60 años de Neiva, encontrar el índice de prevalencia de las demencias en esta población y los factores asociados que pudieran considerarse como posibles factores de riesgo.Métodos. Se trató de un estudio cuantitativo descriptivo de corte transversal y diseño muestral realizado en dos fases consecutivas por un grupo multidisciplinar, aplicando en cada una de ellas los criterios y pruebas más utilizadas en el mundo para estos casos. La población total de adultos mayores en Neiva según proyección hecha para el 2005 fue de 25.142 y la muestra para el estudio fue de 643 tomados en muestreo aleatorio.Resultados. En una muestra significativa de adultos mayores de 60 años seleccionados al azar y proporcionalmente por estrato socioeconómico, se encontró una prevalencia global de demencia de 23.6 por ciento y varios factores de riesgo asociados siendo los principales el bajo nivel de escolaridad (más del 80 por ciento); difíciles condiciones de vida (se agruparon en los estratos más bajos: 92 por ciento); y algunas comorbilidades