Understanding Dementia

Understanding dementia

Dementia is not one disease. Identifying the specific cause changes what to expect, which treatments apply, and how families should plan.

What is dementia?

Dementia is not one disease. It is a term for a decline in memory, thinking, language, or judgment that is severe enough to interfere with everyday life.

Normal aging vs dementia

Some memory change is expected with age. Dementia is different: it interferes with tasks a person used to handle without help.

Mild cognitive impairment (MCI)

MCI is a stage between normal aging and dementia: testing shows a change, but the person still manages daily life independently.

Alzheimer's disease

Alzheimer's disease is the most common cause of dementia. It usually begins with short-term memory difficulty and progresses gradually.

Lewy body dementia

Lewy body dementia combines cognitive change with visual hallucinations, fluctuating alertness, movement changes, and sleep disturbance.

Vascular dementia

Vascular dementia results from strokes or small vessel disease. Slowed thinking and difficulty with planning often stand out more than memory loss.

Frontotemporal dementia

Frontotemporal dementia usually begins between ages 45 and 65 with changes in behavior, judgment, or language rather than memory.

Parkinson's disease dementia

Parkinson's disease dementia develops in some people years after Parkinson's movement symptoms begin.

Mixed dementia

Many older adults have more than one cause of dementia at the same time, most commonly Alzheimer's disease plus vascular changes.

LATE (limbic-predominant age-related TDP-43 encephalopathy)

LATE is an age-related condition that causes memory loss resembling Alzheimer's disease, most often in people over 80.

Reversible contributors to cognitive symptoms

Even when dementia is present, treating reversible contributors can meaningfully improve day-to-day function.