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Study Cohort Information

The ADNI study was designed to approximate an interventional clinical trial cohort. The standards and practices surrounding clinical trials are dynamic and have changed throughout the lifetime of the study, and as such the procedures surrounding enrollment within the ADNI cohort has continuously adapted to the latest trends in order to better serve its purpose as a model data set for trial design.

Participants are assigned to diagnostic cohorts upon enrollment in the ADNI study. This initial categorization is based on a thorough clinical diagnostic evaluation conducted during the screening visit.

The exact criteria for inclusion within each diagnostic category, as well as the categories themselves, have evolved throughout the history of the study. Data users who are interested in working with the ADNI data are encouraged to consult relevant sections of the Procedures Manuals for the different phases for more detailed information.

A high-level summary of the major diagnostic categories used in the study is presented below:

Cognitive Unimpaired

Cognitive
Unimpaired (CU)

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The cognitively unimpaired (CU) arm of the study consists of participants who do not present with evidence of significant cognitive impairment during their initial evaluation.
 
Criteria for assignment to this arm include a Clinical Dementia Rating (CDR) global score of zero and memory box score must be zero.
 
Mini-mental State Exam (MMSE) and Wechsler Logical Memory II sub-scale are also used to establish a CU diagnosis (with specific cut off scores based on educational level).
 
For more information on inclusion criteria for this cohort, and how these criteria have varied between phases, please consult the procedures manuals found on the documentation page.
Mild Cognitive Impairment

Mild Cognitive Impairment (MCI)

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The mild cognitive impairment (MCI) cohort consists of participants who represent an intermediate stage in the progression of dementia. These participants do not meet the diagnostic criteria for AD/dementia cohort, but still present clinically relevant cognitive impairment.
 
Criteria for assignment to this arm include a Clinical Dementia Rating (CDR) global score of 0.5 and memory box score must be at least 0.5. Mini-mental State Exam (MMSE) and Wechsler Logical Memory II sub-scale are also used to establish a MCI diagnosis (with specific cut off scores based on educational level).
 
During the ADNIGO and ADNI2 phases of the study, this cohort was further subdivided into ‘early MCI' and 'late MCI' cohorts, but these two categories were merged again into 'MCI’ during the ADNI3 phase.
 
For more information on inclusion criteria for this cohort, and how these criteria have varied between phases, please consult the procedures manuals found on the documentation page.
Dementi/AD

Dementia/AD
 

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The Dementia/AD cohort consists of participants whose initial clinical presentation is consistent with a diagnosis of dementia. This cohort is intended to be representative of individuals with Alzheimer's disease (AD).
 
Criteria for assignment to this arm include a Clinical Dementia Rating (CDR) global score of 0.5 or 1. Mini-mental State Exam (MMSE) and Wechsler Logical Memory II sub-scale are also used to establish an AD/Dem diagnosis (with specific cut off scores based on educational level).
 
Screening criteria are in place to exclude prospective participants in the dementia arm whose symptoms likely arise from a non-Alzheimer's etiology, such as Frontotemporal dementia (FTD) or Parkinson’s disease (PD).
 
For more information on inclusion criteria for this cohort, and how these criteria has varied between phases, please consult the procedures manuals found on the documentation page.
Remote Cohorts

Remote Cohorts
 

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The remote cohort is new for ADNI4. Unlike the other cohorts, participants in the remote cohort do not necessarily undergo in-clinic evaluation (although some remote participants may be referred to the in-clinic arm of the study, and CU/MCI participants enrolled in the in-clinic arm are encouraged to enroll in the remote cohort as well.)
 
For more information on the remote cohort, please consult the ADNI4 page.
2024 Alzheimer’s Disease Neuroimaging Initiative
This website is funded by the Alzheimer’s Disease Neuroimaging Initiative