Investigating Neurocognitive Disorders Epidemiology

This is a prospective cohort study with the main purpose of predicting progression neurocognitive disorders in Thai population. The main predictor variables to be evaluated are plasma phosphorylated tau (p-tau) level and cognitive test scores, which will be combined using statistical/computational modeling. Additionally, it seeks to evaluate biomarkers for diagnosing disease pathologies, understand their correlation with clinical outcomes, and explore the socioeconomic impact of neurocognitive disorders. The study invites both participants for biospecimen collection, structured interviews, and cognitive examinations and schedules follow-up visits annually or biennially.

The INDE study is a prospective cohort aimed at investigating the natural history and epidemiology of neurocognitive disorders in Thailand. Its primary objective is to develop a predictive model that combines biomarkers (eg. plasma phosphorylated tau) and cognitive performance to accurately predict cognitive decline. Additional objectives include cross-sectional evaluation of various biomarkers for diagnosing disease pathologies, identifying correlations between biomarkers and clinical outcomes, understanding the impact of receiving a biological diagnosis, describing the epidemiology of neurocognitive disorders including risk factors and social determinants of health (SDH), exploring the socioeconomic consequences of these disorders, and establishing a biorepository for future research. The study invites both healthy volunteers and patients referred from memory clinics to participate in a 4-hour visit during which various research procedures are conducted: collection of biospecimens (blood, saliva, sweat), structured interviews covering symptoms, comorbidities, risk factors, SDH, and quality of life, as well as a comprehensive cognitive examination. Participants are scheduled for annual or biennial follow-up visits based on their cognitive status. For those consenting to specific disclosures, investigators provide some biomarker test results and offer post-test counseling based on available research literature. Depending on current funding, a subset of participants meeting additional criteria may also undergo evaluation using appropriate neuroimaging or cerebrospinal fluid (CSF) biomarkers.

Eligibility Criteria:
1. Cognitively Healthy Individuals

   INCLUSION CRITERIA
   * Demonstrate normal cognitive function within the expected range on objective cognitive tests.
   * Proficient in speaking and understanding Thai without the need for a translator to participate.

   EXCLUSION CRITERIA
   * Significant neurological or uncontrolled psychiatric illness.
   * Significant unstable systemic condition or end-stage organ failure that affects study participation.
2. Mild Cognitive Impairment

   INCLUSION CRITERIA
   * Display impaired/abnormal performance on objective cognitive tests.
   * Does not meet criteria for dementia per NIA-AA (or major neurocognitive disorder per DSM-5).
   * Proficient in speaking and understanding Thai without the need for a translator to participate.

   EXCLUSION CRITERIA
   * Significant neurological or uncontrolled psychiatric illness.
   * Significant unstable systemic condition or end-stage organ failure that affects study participation.
3. Late Onset Dementia

   INCLUSION CRITERIA
   * Display impaired/abnormal performance on objective cognitive tests.
   * Meets criteria for dementia per NIA-AA (or major neurocognitive disorder per DSM-5), including dementia due to Alzheimer's disease or other causes.
   * Begins to experience symptoms, identified by the physician as a part of dementia continuum, occurring after the age of 65.
   * Proficient in speaking and understanding Thai without the need for a translator to participate.

   EXCLUSION CRITERIA
   * Significant neurological or uncontrolled psychiatric illness.
   * Significant unstable systemic condition or end-stage organ failure that affects study participation.
4. Early Onset Dementia

INCLUSION CRITERIA

* Display impaired/abnormal performance on objective cognitive tests.
* Meets criteria for dementia per NIA-AA (or major neurocognitive disorder per DSM-5), including dementia due to Alzheimer's disease or other causes.
* Begins to experience symptoms, identified by the physician as a part of dementia continuum, occurring before the age of 65.
* Proficient in speaking and understanding Thai without the need for a translator to participate.

EXCLUSION CRITERIA

* Significant neurological or uncontrolled psychiatric illness.
* Significant unstable systemic condition or end-stage organ failure that affects study participation.