Doctors diagnose dementia stages by looking at a person’s symptoms, memory, thinking skills, and daily life changes. They use simple talks, tests, scans, and checkups to figure out if it’s early, middle, or late stage.
The process starts with a doctor’s visit. The doctor asks the patient and family about health history, daily habits, and any changes in behavior or memory. For example, they might ask if the person forgets recent events, struggles with work tasks, or has trouble focusing. This helps spot if symptoms match early stages, like mild forgetfulness in stage 3, where friends and family start noticing issues.
Next, doctors give quick cognitive tests. These check memory, attention, language, and problem-solving. Common ones include the Mini-Mental State Examination, which scores thinking skills out of 30 points. The Mini-Cog asks someone to remember three words and draw a clock. The Montreal Cognitive Assessment looks at drawing, naming objects, and short-term memory. Scores help show if changes are mild, like in stage 4 where short-term memory fades and new tasks feel hard, or moderate in stage 5 when daily chores need help.
Blood and urine tests rule out other problems, like vitamin shortages or infections, that mimic dementia. Brain scans play a big role too. CT or MRI scans check for strokes, tumors, or shrinkage that point to vascular dementia or later stages. PET scans spot amyloid proteins in Alzheimer’s, even before symptoms show. One new method uses age and a single amyloid PET scan to guess how long until symptoms start or which stage someone is in.
In later stages, like stage 6, doctors note bigger signs such as not recognizing family, needing full-time care, or physical issues like swallowing trouble. They repeat tests over time to track if the condition worsens from mild to severe. A neurologist might do a full neurological exam to pinpoint the type and stage.
Family input is key, as they see changes better than tests sometimes. While no test proves dementia until after death for Alzheimer’s, these steps give a clear picture of the stage and guide care.
Sources
https://medicine.washu.edu/news/time-until-dementia-symptoms-appear-can-be-estimated-via-brain-scan/
https://www.alzsd.org/dementia-diagnosis-next-steps/
https://www.wellmedhealthcare.com/patients/healthyliving/conditions-diseases/what-are-the-stages-of-dementia/
https://www.hmpgloballearningnetwork.com/site/altc/content/diagnosis-and-management-dementia-long-term-care
https://creyos.com/blog/cognitive-tests-for-dementia
https://www.myfloridaneurology.com/cognitive-memory-disorder-clinic/dementia
https://www.alzheimers.org.uk/about-dementia/dementia-diagnosis/how-to-get-dementia-diagnosis
https://beingpatient.com/journey-to-diagnosis/
https://www.dignityhealth.org/north-state/services/neurology/neurological-conditions/dementia/signs-and-symptoms
https://www.ariadnelabs.org/2025/12/16/indexing-dementia-diagnosis-toolkit/
