Alzheimer's Disease Assessment Scale-Cognitive
Alzheimer's Disease Assessment Scale-Cognitive Subscale · Also known as: ADAS-Cog, ADAS-Cog14, ADAS-Cog13
The Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) is a clinician-administered cognitive assessment instrument designed specifically to measure cognitive decline in Alzheimer's disease. Developed by Rosen, Mohs, and Davis in 1984 and published in the American Journal of Psychiatry, the ADAS-Cog has become the gold standard outcome measure in pharmaceutical trials of antidementia drugs. It is sensitive to disease progression and capable of detecting cognitive change over periods as brief as 6–12 months.
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When to use it
The ADAS-Cog is indicated for measuring cognitive decline in patients with mild-to-moderate Alzheimer's disease, tracking disease progression in clinical practice, and as the primary cognitive outcome in pharmaceutical trials. It is less suitable for very mild cognitive impairment (ceiling effect) or severe dementia (floor effect). The ADAS-Cog is not appropriate for screening or diagnosis alone and should always be integrated with clinical assessment, functional evaluation, neuroimaging, and biomarkers. It is particularly valuable in research settings and specialized memory clinics.
Strengths & limitations
- Gold standard in Alzheimer drug trials — sensitivity to treatment effects and disease change has been established across thousands of patients in clinical trials, making it the benchmark cognitive measure in neurodegenerative disease research.
- Sensitivity to change — detects clinically meaningful cognitive decline over 6–12 months in mild-to-moderate Alzheimer's disease, more reliably than the MMSE in this range.
- Comprehensive cognitive sampling — assesses memory, language, praxis, attention, and visuospatial function, providing a multidimensional profile rather than a single global score.
- Extensive normative data — available for diverse populations, ages, and disease stages, with published conversion tables linking ADAS-Cog to MMSE scores.
- Long administration time — 30–40 minutes is burdensome in busy clinical settings and unsuitable for frequent monitoring or cognitively impaired patients with poor cooperation.
- Limited utility at extremes — ceiling effect in cognitively normal individuals and those with minimal impairment; floor effect in severe dementia where almost all patients score near maximum.
- Requires clinical training — administration and scoring are more complex than the MMSE and demand clinician expertise to ensure standardization and reliability.
- Not diagnostic — ADAS-Cog measures cognitive change but does not diagnose Alzheimer's disease or differentiate Alzheimer's from other dementias.
Frequently asked
Should I use the 11-item or 14-item version of the ADAS-Cog?
The ADAS-Cog11 is the historical standard and most commonly used in longitudinal clinical practice. The ADAS-Cog14 is preferred in pharmaceutical trials because the additional items increase sensitivity to treatment-related cognitive change. If you are comparing to published norms or prior assessments, maintain consistency with the version used previously. Never mix scores across versions in the same patient's longitudinal record.
What is a clinically meaningful change on the ADAS-Cog?
A change of 4 or more points on the ADAS-Cog11 over 6–12 months is considered clinically meaningful. Improvement (negative change) of 2–3 points may reflect drug effect in trials. In routine practice, a change of 3–5 points over 12 months often reflects true disease progression. Always interpret change in context of the baseline score, disease stage, and interval between assessments.
Is ADAS-Cog sensitive enough to detect drug effects in mild cognitive impairment?
The ADAS-Cog has limited sensitivity in pure MCI because scores are near-normal; a ceiling effect limits the range of possible change. The ADAS-Cog is optimized for mild-to-moderate Alzheimer's disease (MMSE equivalent 10–24). For MCI trials, supplementary measures of memory and executive function (e.g., neuropsychological batteries, RBANS) are typically needed alongside ADAS-Cog.
Can the ADAS-Cog be administered remotely by videoconference?
Remote administration is feasible but reduces standardization and scoring reliability, particularly for items requiring precise visual or motor response assessment (e.g., object naming, construction). If remote administration is essential, use video conferencing with high video quality, ensure a quiet environment, and document the method. In-person administration is strongly preferred for research and regulatory trials.
Sources
- Rosen, W. G., Mohs, R. C., & Davis, K. L. (1984). A new rating scale for Alzheimer's disease. American Journal of Psychiatry, 141(11), 1356-1364. DOI: 10.1176/ajp.141.11.1356 ↗
- Mohs, R. C., Knopman, D., Petersen, R. C., et al. (1997). Development of cognitive instruments for use in clinical trials of antidementia drugs: Additions to the ADAS and MMSE. Alzheimer Disease and Associated Disorders, 11(Suppl 2), 13-21. link ↗
- Pfeffer, R. I., Inoue, S. K., & Chance, G. R. (2000). Diagnostic criteria for dementia: Revision of the DSM-IV and ICD-10. Journal of the American Geriatrics Society, 48(12), 1572-1578. link ↗
How to cite this page
ScholarGate. (2026, June 3). Alzheimer's Disease Assessment Scale-Cognitive Subscale. ScholarGate. https://scholargate.app/en/neuropsychology/adas-cog
Which method?
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