Cerebrovascular Correlates of Dementia in Rural Communities - The Three Villages Study

Study Overview
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Brief Summary
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This study aims to assess the prevalence and severity of dementia in an established cohort of community-dwelling older adults living in three neighboring rural Ecuadorian villages (Atahualpa, El Tambo, and Prosperidad), as well as to evaluate clinical and neuroimaging correlates of dementia in the study population. By the use of the Clinical Dementia Rating Scale (CDRS), the study also aims to assess the lower cutoff of the MoCA that better correlates with the occurrence of dementia in the study population. In addition, this study will provides grounds for the initiation of a prospective cohort study to assess factors influencing the development of dementia in the follow-up.

Detailed Description
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The Three Villages Study is a population-based prospective cohort study designed to reduce the increasing burden of cognitive decline and dementia in rural Ecuador. Before the study, our Executive Committee met with community leaders to explain the aims of the study and to learn about the culture and traditions of villagers. Field personnel were trained to assure uniformity in data collection. With the aid of satellite view (Google Earth, Google Inc., Mountain View, CA), updated sketches of the villages were performed to identify blocks and houses. The study initially will follow a 3-Phase cross-sectional design. During Phase I, Atahualpa, El Tambo, and Prosperidad residents aged 60 years or more will be identified by means of a door-to-door survey and interviewed with validated questionnaires to identify those with relevant risk factors and suspected conditions of interest. In Phase II, certified neurologists will examine suspected cases as well as random samples of negative individuals, to assess reliability of field instruments and to determine prevalence of the investigated conditions. In Phase III, enrolled individuals will be invited to undergo complementary tests. Thereafter, incoming residents will be recruited and followed-up by means of yearly door-to-door surveys and other overlapping sources to estimate incidence of the disorders of interest.

Official Title
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Cerebrovascular Correlates of Dementia in Community-dwelling Older Adults Living in Remote Rural Communities - The Three Villages Study. Methodology and Operational Definitions.

Conditions
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Dementia, Cardiovascular Risk Factor, Atherosclerosis, Cerebral Small Vessel Diseases, Cognitive Decline

Intervention / Treatment
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* Diagnostic Test: Neuroimaging studies


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Individuals aged 60 years of more residing in Atahualpa, El Tambo, and Prosperidad, who signed a comprehensive informed consent form. - Exclusion Criteria: Severely disabled individuals in whom interviews and procedures cannot be performed -

Ages Eligible for Study
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Minimum Age: 60 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| The Three Villages Cohort<br>Individuals aged 60 years or more identified by means of door-to-door surveys, living in Atahualpa, El Tambo, and Prosperidad. Individuals will be interviewed with validated field instruments, and there will be invited for the practice of complementary exams to recognize markers of aterosclerosis and cerebral small vessel disease. | Diagnostic Test: Neuroimaging studies<br>* Complementary exams are not invasive and will be performed in enrolled individuals who sign a comprehensive informed consent form<br>* Other names: Ankle-brachial index determinations;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess the prevalence and severity of dementia in the study population | The Clinical Dementia Rating Scale will be applied to all participants | One year | 
| To assess cerebrovascular correlates of mild cognitive impairment and dementia in the study population | Neuroimaging studies, ultrasound examination of extracranial carotid arteries, and ankle-brachial index determinations will be used to assess the presence of large vessel aterosclerosis and cerebral small vessel disease in the study population | One year | 
| To assess cognitive decline in the follow-up | Enrolled individuals will be prospectively followed every year for up to five years, and will be re-assessed to determine the progression of cognitive impairment and its relationship with markers of aterosclerosis and cerebral small vessel disease | five years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess cutoffs of the Montreal Cognitive Assessment useful to differentiate normal cognitivion from mild cognitive impairment, and mild cognitive impairment to dementia in the study population | The MoCA was mainly designed to separate normal individuals to those with MCI. However, a major limitation of the MoCA is its lack of accuracy for identifying persons with dementia. Therefore, the use of more complex field instruments (yet, feasible to apply in individuals living in rural settings) is needed to determine the burden of dementia and its cerebrovascular correlates in rural communities. In this regard, the Clinical Dementia Rating Scale (CDRS) is a useful tool to assess people living in these settings for establishing the burden and severity of dementia as well as to further assess clinical and neuroimaging correlates of this condition. | five years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dementia, Cognitive performance, Vascular diseases, Rural Ecuador, Atahualpa, El Tambo, Prosperidad, Three villages study