The Clinical Dementia Rating (CDR) scale stages memory, thinking, and daily function. Mild cognitive impairment typically shows as a global score of 0.5, with a Sum of Boxes total often between 0.5 and 4.0. The rating comes from a semi-structured interview with both the patient and a reliable informant. As described by Clinical Medicine & Research in the Clinical Medicine & Research description, it rates six areas: memory, orientation, judgment and problem-solving, community affairs, home and hobbies, and personal care.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Table of Contents
- How is the rating calculated?
- What does an MCI-range result mean?
- What can the score say about what happens next?
- What are the limits and how should families use results?
How is the rating calculated?
Memory anchors the global score. The other five domain scores decide whether the final stage stays at the memory score or shifts up or down. Personal care is scored without a 0.5 level.
Doctors also add the six domain scores into a second score, CDR-Sum of Boxes. The total runs from 0 to 18. It gives a finer picture than the single global stage.
What does an MCI-range result mean?
A global 0.5 means questionable or very mild impairment. InformedHealth places this stage at mild cognitive impairment in the InformedHealth CDR guide, below mild dementia at 1, moderate dementia at 2, and severe dementia at 3.
The Sum of Boxes total adds detail within that stage. The same guide interprets about 0.5 to 4.0 as mild cognitive impairment rather than dementia. A person at the lower end may need only reminders, while a person near the higher end may need more help with chores, hobbies, or community tasks.
What can the score say about what happens next?
A higher starting Sum of Boxes strongly predicts a move from predementia to dementia. A 2022 study reported in the Frontiers in Aging Neuroscience study found hazard ratios rising from about 1.5 at 0.5 to about 5.2 at 4.5 or higher, compared with a score of 0.
The chance of returning to normal thinking falls as scores rise. The study found reversion in about 12.5% at 0.5, 5.6% at 1.0 to 2.0, 0.9% at 2.5 to 3.5, and 0% at 4.0 or higher. A low score leaves more room for stability or improvement, while a high score points toward closer follow-up.
What are the limits and how should families use results?
The CDR needs a knowledgeable informant and about 30 minutes. It depends on clinician judgment, not self-report alone. It stages severity but does not prove Alzheimer's disease, which needs amyloid and tau biomarker testing.
Clinicians use the global stage to identify MCI and plan care. They prefer Sum of Boxes to track decline over time and measure change in trials. Families can prepare for the visit with these steps:.
- Bring someone who sees daily memory, chores, hobbies, and community activities.
- Allow about 30 minutes for the joint interview.
- Ask which score the clinic will follow: global stage for care decisions or Sum of Boxes for change over time.
