Part 2 · Course and diagnosis
Stages and symptoms
Alzheimer's takes away abilities in a fairly fixed order, from the most demanding tasks to the most basic ones. Press Play, or pick a stage, and watch which everyday abilities are kept and which are lost.
Schematic. Stages are drawn equal width, not to time. The year spans above come from one model (Vermunt 2019, someone with preclinical Alzheimer's at age 70). Reisberg's own average durations for each FAST stage are widely repeated but could not be checked against the 1988 paper (unverified), so they are not shown. CDR and MMSE are aligned to FAST approximately: the scales were built separately.
After a diagnosis of MCI: who progresses?
Mild cognitive impairment (MCI) means thinking has declined more than expected for age while daily life is still independent. It is a risk state, not a sentence. Two groups of 100 people with MCI are followed for five years below.
Illustration. Hollow figure: no dementia yet. Solid figure: progressed to dementia. It applies each published annual rate to those not yet converted, every year, which is a simplification: real risk differs from person to person.
Not always memory first
Typical Alzheimer's starts with memory, because the first tangles form in the medial temporal lobe. Some people start with vision, language or planning instead. These atypical forms are much more common when the illness starts before 65. 206
Each square is one person in 100. "About one third" is drawn as 33.
Beyond memory: mood and behaviour
Pooled prevalence in Alzheimer's, Neuropsychiatric Inventory. Studies varied a lot.
How long, and how the illness ends
Survival is measured in years
People aged 65 and older live on average 4 to 8 years after a diagnosis of Alzheimer's dementia, and some live as long as 20 years. Across studies, median survival from onset was 3.3 to 11.7 years, most often 7 to 10. 2,487
Age at diagnosis matters most
Median survival was 8.3 years when diagnosed at 65 and 3.4 years at 90, with no significant difference between men and women. Across studies, age was a consistent predictor of death; male sex was a less consistent one. 64,487
Pneumonia is the most common final event
Pneumonia is the most commonly identified immediate cause of death, and swallowing problems can lead to aspiration. In one autopsy series, respiratory causes accounted for 55.5% of deaths in Alzheimer's. 2,65
Advanced dementia in nursing homes
In the CASCADE study of 323 residents with advanced dementia, 54.8% died over 18 months. Eating problems affected 85.8% and pneumonia 41.1%. See Living with dementia for planning and end-of-life care. 358