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Printed on 7/21/2026
For informational purposes only. This is not medical advice.
The AD8 is a brief informant-based cognitive screening interview focused on perceived change in memory, judgment, orientation, and daily cognitive function. Each endorsed change item scores 1 point (total 0-8). A score of 2 or higher is a commonly used threshold for cognitive impairment signal.
Formula: AD8 total = count of endorsed change items (0-8).
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The AD8 (Alzheimer's Disease 8) is a brief informant-based screening tool consisting of 8 questions about changes in cognitive function and everyday activities. Select an informant who knows the patient well and has regular contact — typically a spouse, adult child, or close friend. The informant is asked to compare the patient's current functioning to their functioning a few years ago (not necessarily a fixed 10-year reference like IQCODE). For each of the 8 items, the informant answers: Yes, a change (score 1); No, no change (score 0); or I don't know (score 0). The 8 items cover: memory changes (judgment problems, memory loss — including forgetting dates), orientation problems (repeating questions or stories in a short period), forgetting the correct year or month, difficulty managing finances or balancing accounts, difficulty remembering appointments/medications, and problems thinking and reasoning.
AD8 total score = sum of items answered 'Yes, a change' (0-8 total). Items answered 'No, no change' or 'I don't know' score 0. The AD8 is specifically designed for rapid informant-based screening — total administration time is typically 3-5 minutes. It can be administered as a brief structured interview by a clinician or nurse, or completed as a self-administered questionnaire by the informant in the waiting room before a clinic visit. The AD8 was developed at Washington University in St. Louis and validated against CDR, MMSE, and clinical dementia diagnosis.
AD8 score interpretation: 0-1 = No significant cognitive impairment signal from informant perspective — does not exclude early dementia, but informant has observed no or minimal change. 2 or above = Positive screen for possible cognitive impairment — trigger formal cognitive assessment. The AD8 cutoff of 2 or above achieves sensitivity approximately 85% and specificity approximately 86% for clinical dementia (CDR 0.5 or above) in validation studies. An AD8-positive result (2 or above) in a clinic setting should trigger: brief cognitive assessment (MMSE or MoCA), functional assessment, review of medications, laboratory workup (CBC, CMP, TSH, B12), and follow-up appointment with comprehensive cognitive evaluation if indicated.
Primary care physicians, family medicine practitioners, internists, practice nurses
The AD8's 3-5 minute informant administration makes it one of the most practical tools for busy primary care settings. In the CMS Annual Wellness Visit (AWV), cognitive impairment detection is a required component. Providing the AD8 questionnaire to accompanying family members or caregivers in the waiting room, before the physician enters, generates validated cognitive screening data without requiring additional physician time. AD8 of 2 or above alerts the physician to address cognitive concerns in the visit and schedule a comprehensive cognitive evaluation.
Memory clinic nurses, intake coordinators, geriatric psychiatry intake teams
AD8 administered at memory clinic intake (completed by the accompanying family member while the patient completes self-report measures) provides rapid pre-screening data before the formal evaluation. AD8 score patterns provide initial triage information: AD8 of 0-1 in a patient referred for 'memory concerns' suggests the referring clinician or patient's subjective concerns may outpace informant-observed functional changes (low likelihood of significant dementia). AD8 of 4 or above with high informant agreement suggests a high likelihood of clinically significant cognitive impairment requiring urgent comprehensive assessment.
Emergency physicians, emergency nurses, hospital-based geriatric triage teams
Cognitive impairment is common in older adult emergency department (ED) presentations and frequently unrecognized. When a family member or caregiver accompanies a patient to the ED, rapid AD8 administration provides valuable baseline cognitive data. AD8 of 2 or above in an ED presentation suggests pre-existing cognitive impairment — important context for: medication choices, consent discussions, delirium superimposition evaluation, and discharge planning. ED nursing triage protocols increasingly include brief cognitive screening for older adults using tools like AD8.
Nursing home nurses, MDS coordinators, nursing home physicians
AD8 administered to a family member at nursing home admission provides a rapid informant-based cognitive baseline to complement BIMS direct assessment. This is particularly valuable when the patient is admitted during delirium or acute medical illness (when BIMS underestimates baseline cognitive function). AD8 results document whether the resident had pre-existing cognitive impairment before admission — informing care planning, BPSD management approach, and communication strategies.
Clinical researchers, Alzheimer's disease prevention trials, population health researchers
AD8 is widely used in Alzheimer's disease research for rapid pre-screening of potential study participants. Its brief administration allows telephone or online pre-screening before in-person evaluation. AD8 of 2 or above triggers in-person cognitive assessment for potential dementia cases in prevalence studies or clinical trial eligibility screening. The Washington University (Galvin et al.) validation in multiple populations supports AD8 use across diverse demographic groups in research settings.
Public health teams, community health workers, Alzheimer's disease advocacy organizations
AD8 can be administered by trained non-clinical community health workers in community settings — senior centers, health fairs, community events. Its simple binary Yes/No format for informants makes it accessible for administration by lay health workers. Community AD8 screening programs using telephone interviews have demonstrated feasibility for early dementia case finding in community populations. AD8 of 2 or above in a community screening context triggers referral to primary care or memory clinic for formal evaluation.
One of the most efficient AD8 administration strategies is providing the questionnaire to accompanying family members or caregivers in the waiting room before the clinic visit. This generates informant data without requiring physician time for administration. Practice staff can provide the AD8 questionnaire at check-in when an accompanying person is present. The completed AD8 is available when the physician enters, enabling targeted cognitive assessment within the routine visit flow.
Unlike IQCODE (which anchors to 10 years ago), the AD8 asks the informant to compare current functioning to 'a few years ago.' This flexible recent reference period means AD8 is sensitive to relatively rapid changes (over months to years) that might be missed by IQCODE's 10-year anchor. The AD8 is therefore particularly useful for detecting more recent-onset cognitive changes. However, this also means a recently identified change in a patient with long-standing prior cognitive impairment may not fully reflect the entire disease history.
A positive AD8 (2 or above) indicates the informant has observed significant cognitive changes warranting clinical evaluation. It does not diagnose dementia, Alzheimer's disease, or any specific cognitive disorder. Many conditions can produce a positive AD8: Alzheimer's disease, vascular dementia, other dementias, depression, medication effects, thyroid disorder, B12 deficiency. A positive AD8 always requires formal medical evaluation, not automatic dementia diagnosis or treatment initiation.
Studies comparing AD8 informant version to patient self-completion version show that patients score themselves significantly lower (fewer 'Yes, a change' responses) than informants score them — reflecting anosognosia (reduced insight) in cognitive impairment. Patient self-completion of AD8 has substantially lower sensitivity for dementia detection (~65%) compared to informant completion (~85%). When possible, always administer AD8 to an informant rather than the patient. When no informant is available, document the source and interpret a patient-completed AD8 with understanding that it will likely underestimate the degree of cognitive change.
The combination of AD8 (informant-based) and a brief direct cognitive test (Mini-Cog, MMSE, or MoCA) achieves higher sensitivity and specificity for dementia detection than either tool alone. When both AD8 (2 or above) and Mini-Cog (3 or below) are positive, the positive predictive value for dementia is approximately 90%. When AD8 is positive but Mini-Cog is normal, the discordance warrants clinical judgment — informant may be observing early functional decline before performance-based test impairment becomes evident.
While any AD8 of 2 or above triggers formal assessment, an AD8 of 6-8 suggests widespread, significant informant-observed cognitive and functional decline consistent with moderate-to-severe dementia. High AD8 scores trigger more urgent evaluation: same-day or next-available memory clinic appointment, immediate safety assessment (driving, cooking, medication management, financial vulnerability), and family/carer support activation. AD8 of 6 or above combined with concerning clinical presentation warrants urgent geriatric consultation.
AD8 was developed as a rapid informant interview to detect very mild dementia and is widely used with a >=2 screening threshold.
Higher AD8 scores indicate stronger informant-reported cognitive decline signal and support further diagnostic assessment.
Use when a reliable informant is available and quick screening for possible cognitive impairment is needed in primary or specialist care.
Performance depends on informant quality and may be influenced by limited contact, stress, or baseline expectations.
For related assessments, see IQCODE-16, CDR Global and SLUMS Score.
Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.
April 21, 2026 · trust-baseline
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