A Longitudinal Study to Explore the Impact of Gut Microbiome on Brain Health in Alzheimer's Disease

Eligibility criteria

Inclusion Criteria:
* Cognitively normal group:
  1. normal performance on standardized cognitive tests;
  2. with no cognitive complaints or any concerns (worries).
* SCD group:
  1. self-experienced persistent decline in memory, rather than other domains of cognition;
  2. normal performance on standardized cognitive tests;
  3. failure to meet the criteria for MCI or dementia;
  4. age at onset of SCD ≥ 60 years old;
  5. onset of SCD within the last 5 years;
  6. concerns (worries) associated with SCD;
  7. feeling of worse performance than others of the same age group.
* MCI group:
  1. having impaired scores on both measures in at least one cognitive domain (memory, language, or speed/executive function);
  2. having impaired scores in each of the three cognitive domains (memory, language, or speed/executive function);
  3. the Functional Activities Questionnaire (FAQ)≥9.
* AD dementia group:
  1. meet the criteria for dementia and have impaired daily functional activities;
  2. episodic memory deficit; 3) Clinical Dementia Rating (CDR) ≥ 1.
Exclusion Criteria:
* a history of stroke;
* major depression and anxiety;
* other central nervous system disorders that may cause cognitive impairment, such as Parkinson's disease, tumors, encephalitis, and epilepsy;
* cognitive impairment caused by traumatic brain injury;
* systemic diseases, such as thyroid dysfunction, syphilis and HIV;
* psychosis or congenital mental developmental delay;
* a history of using antibiotics, probiotics, prebiotics, or synbiotics within 3 months;
* the use of corticosteroid, immune stimulating medications, and immunosuppressive agents;
* major gastrointestinal tract surgery in past 5 years;
* severe gastrointestinal diseases, such as irritable bowel syndrome, infammatory bowel disease, severe gastritis, other dysfunction in digestion and absorption, which has been reported to infuence gut microbiota

The sponsor's own eligibility wording, lightly reformatted. The study team makes the final eligibility decision — worth discussing with your doctor.

Eligibility criteria as of 2025-02-20