Clinical Dementia Rating
Also known as: CDR, CDR Scale, Washington University Dementia Rating
The Clinical Dementia Rating (CDR) is a clinician-administered scale that assesses severity of dementia on a 0–3 scale based on interview with the patient and an informed collateral source (e.g., family member). Developed by Morris and colleagues at Washington University School of Medicine, the CDR has become the reference standard for dementia severity assessment in clinical practice and research, particularly for staging Alzheimer's disease.
Key highlights
- Gold standard dementia staging scale used in thousands of clinical trials and longitudinal cohort studies with extensive normative data across age groups and populations.
- Relies on collateral information from informant, reducing reliance on patient self-report and improving accuracy, especially in cognitive impairment or anosognosia.
- Multidimensional assessment across cognitive and functional domains provides holistic dementia staging beyond memory alone.
- Weighted box score algorithm demonstrates strong predictive validity for disease progression, treatment response, and functional outcomes.
Intuition
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How it works
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When to use it
CDR is the standard instrument for clinicians assessing dementia severity in memory clinics, neurology, geriatrics, and neuroscience research. Use at baseline to establish dementia stage, during follow-up to monitor disease progression, and in drug trials to assess cognitive and functional response to therapeutic interventions. CDR is particularly valuable for diagnostic clarity when distinguishing normal aging, MCI, and dementia.
Strengths & limitations
- Gold standard dementia staging scale used in thousands of clinical trials and longitudinal cohort studies with extensive normative data across age groups and populations.
- Relies on collateral information from informant, reducing reliance on patient self-report and improving accuracy, especially in cognitive impairment or anosognosia.
- Multidimensional assessment across cognitive and functional domains provides holistic dementia staging beyond memory alone.
- Weighted box score algorithm demonstrates strong predictive validity for disease progression, treatment response, and functional outcomes.
- Requires training and clinical judgment to administer reliably; not a brief screening tool and demands clinician expertise in dementia assessment.
- Dependent on availability and cooperation of collateral informant; CDR cannot be reliably scored without informant information.
- Global score resolution is limited to five categories (0, 0.5, 1, 2, 3); may lack sensitivity to subtle changes in longitudinal tracking.
- Does not assess behavioral or neuropsychiatric symptoms commonly present in dementia, focusing instead on cognition and function.
Common pitfalls
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Applications
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Frequently asked
What is the difference between CDR and MMSE or MoCA?
MMSE and MoCA are brief cognitive screening tests administered directly to the patient. CDR is a clinician-rated staging scale using patient and informant interview—it measures dementia severity and functional impact, not raw cognitive test scores. Use MoCA or MMSE for screening; use CDR for staging after dementia diagnosis.
Can CDR be administered without an informant?
Ideally no. CDR reliability depends on collateral information from someone who knows the patient's baseline function. If an informant is unavailable, CDR can be attempted using the patient's self-report, but confidence in scoring is reduced, especially in cases of anosognosia (lack of insight into cognitive deficits).
What does a CDR of 0.5 mean?
CDR 0.5 indicates questionable or very mild cognitive and functional decline. Some patients progress to dementia (CDR ≥1), while others remain stable or revert to normal cognition. CDR 0.5 typically represents mild cognitive impairment (MCI), but the diagnosis requires additional neuropsychological testing and functional assessment.
How often should I administer CDR to track disease progression?
Annual CDR assessment is standard for stable patients. More frequent assessment (every 6 months) is appropriate for patients at higher risk of rapid progression or in clinical trials assessing disease-modifying therapies. In advanced dementia, annual assessment is typically sufficient.
Sources
- 1.Morris, J. C. (1993). The Clinical Dementia Rating (CDR): current version and scoring rules. Neurology, 43(11), 2412–2414.
- 2.McKhann, G., Drachman, D., Folstein, M., Katzman, R., Price, D., & Stadlan, E. M. (1984). Clinical diagnosis of Alzheimer's disease: report of the NINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease. Neurology, 34(7), 939–944.
- 3.Hugonot-Diener, L., Ritter-Hrncirik, C., & Amieva, H. (2008). Clinical Dementia Rating (CDR) in epidemiology and dementia screening. Neuropsychology, 22(4), 529–534.
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Cite this page
ScholarGate. (2026, June 3). Clinical Dementia Rating. ScholarGate. https://scholargate.app/rehabilitation/cdr-dementia-rating