ToolsCalculators
Clinical Dementia Rating (CDR) Scale
Stages dementia severity from six cognitive/functional domains, using memory as the anchor domain.
Clinical Dementia Rating (CDR) Scale
Memory
Orientation
Judgment and problem solving
Community affairs
Home and hobbies
Personal care
ResultGlobal CDR 0.0
No dementia.
- Global CDR
- 0.0
- Sum of boxes (CDR-SB)
- 0.0 / 18
When to use
- Staging the severity of cognitive impairment and dementia in a patient with a known or suspected neurodegenerative disorder.
- Tracking disease progression over time using the sum-of-boxes score, e.g. in clinical trials.
Formula
Six domains (memory, orientation, judgment/problem solving, community affairs, home/hobbies, personal care) are each rated 0, 0.5, 1, 2, or 3 (personal care has no 0.5 option). Memory is the primary category. Global CDR = memory score if at least 3 of the 5 secondary domains match it; otherwise the global score shifts toward whichever side (higher or lower than memory) has 3 or more secondary domains, using the modal score on that side. Sum of boxes (CDR-SB) is the simple sum of all six domain scores (range 0-18).
Pearls and pitfalls
- The global CDR (0, 0.5, 1, 2, 3) is used for staging; the sum of boxes is more sensitive to change and preferred for longitudinal/trial use.
- Requires a semi-structured interview with the patient and a reliable informant; it is not a self-report questionnaire.
- This tool implements the published anchoring rules (memory as primary category; explicit rules for memory = 0 and 0.5); in the small minority of box-score combinations that are genuinely ambiguous, the result defaults toward the memory score and should be cross-checked against the full scoring worksheet.