Dementia is not normal aging—even past age ninety
Dementia is a major neurocognitive syndrome: memory, thinking, behavior and motor control decline until everyday tasks fail. Alzheimer’s is the most common form, but strokes and many diseases can cause it. Aging is the biggest risk factor, yet many people over ninety never develop dementia.
Dementia is an umbrella for a broad decline in thinking severe enough to disrupt daily life. Memory problems usually come with trouble in at least one other area, most often language, but also attention, problem solving or orientation, which is why getting lost and wandering are common signs. Behavioural and psychological changes affect more than 90% of people at some point: agitation, disinhibition, depression, apathy, hallucinations and shifts in personality toward more negativity and less conscientiousness.
Most forms, including Alzheimer's, Lewy body dementias and frontotemporal dementia, are neurodegenerative diseases in which misfolded proteins are a hallmark. After Alzheimer's, the next most frequent type is vascular dementia, caused by disease of the brain's blood vessels. Strokes and head injuries can also lead to it, and Parkinson's disease has its own subtype.
Doctors usually describe three stages. In the mild stage others notice the changes and some help is needed, so planning future care is advised early. The moderate stage brings worse memory, difficulty recognising familiar faces, and in the neurodegenerative forms a loss of insight into the illness. Late-stage patients turn inward, need round-the-clock supervision and often struggle to swallow. Before all this there may be a prodromal phase of mild cognitive impairment, now called mild neurocognitive disorder, which does not always progress and sometimes resolves. Occasionally a person regains startling clarity for a short time, sometimes shortly before death.
Diagnosis relies on the history, cognitive tests and imaging, with blood tests to exclude reversible causes such as an underactive thyroid. Drugs such as donepezil may help a little in mild to moderate stages. As of 2025 dementia was the seventh leading cause of death worldwide, with about 10 million new cases a year, roughly one every three seconds, and Britain now counts it as its top killer.
Source: Dementia
