Glossary

A

Activities of Daily Living (ADLs)

The basic self-care tasks people do every day — bathing, dressing, eating, using the toilet, and moving around. Doctors and caregivers often track ADLs to see how much support someone needs.

Advance directive

A legal document that states a person's wishes for medical care if they become unable to speak for themselves. It's worth setting up early, while someone with Alzheimer's can still clearly express their preferences.

Amyloid plaques

Clumps of a protein called beta-amyloid that build up between brain cells in Alzheimer's disease. They're one of the two hallmark changes seen in the brain (the other is tau tangles).

Anosognosia

When a person is genuinely unaware of their own memory or thinking problems — not denial, but the illness itself affecting their ability to notice the changes. It's common in Alzheimer's and can make it hard to convince someone they need help.

APOE (apolipoprotein E)

A gene that comes in a few variants. One variant, APOE e4, is linked to a higher chance of developing Alzheimer's — but having it doesn't mean someone will definitely get the disease, and not having it doesn't rule it out.

C

Caregiver burnout

Physical, emotional, and mental exhaustion from the ongoing demands of caregiving. It's common, it's not a personal failure, and it's a real reason to ask for respite care or support.

Cholinesterase inhibitor

A type of medication (examples include donepezil and rivastigmine) that can temporarily help with memory and thinking symptoms in some people with Alzheimer's. It doesn't stop the underlying disease.

Clinical trial

A research study that tests whether a new treatment is safe and whether it works, using real volunteers. Trials happen in phases, starting small (mostly testing safety) and growing larger (testing effectiveness) as a treatment shows promise.

Cognitive assessment (screening)

A short set of questions and tasks a doctor uses to check memory, attention, and thinking skills. It's a screening tool, not a diagnosis on its own — a positive result usually leads to further testing.

D

Delirium

A sudden, often short-term state of confusion, frequently caused by infection, medication, surgery, or dehydration. It can look like dementia but comes on quickly and is often reversible — which is why sudden confusion in an older adult should always be checked out.

Dementia

An umbrella term for a decline in memory or thinking severe enough to interfere with daily life. Alzheimer's disease is the most common cause of dementia, but not the only one.

E

Early-onset Alzheimer's

Alzheimer's disease that begins before age 65. It's less common than the typical late-onset form and is more likely to run in families.

Executive function

The mental skills used to plan, organize, make decisions, and manage time — like following a recipe or paying bills. Trouble with executive function is often an early sign of Alzheimer's, sometimes before memory problems become obvious.

F

Frontotemporal dementia

A group of dementias caused by damage to the front and side parts of the brain, often affecting personality, behavior, and language before memory. It tends to start at a younger age than Alzheimer's, often in the 40s to 60s.

H

Hospice care

Care focused on comfort, not cure, typically for someone expected to live six months or less. For advanced Alzheimer's, hospice can support both the patient and the family, often at home.

L

Lewy body dementia

A type of dementia caused by abnormal protein deposits (Lewy bodies) in the brain. It often includes visual hallucinations, fluctuating alertness, and movement symptoms similar to Parkinson's disease, alongside memory changes.

M

Memantine

A medication used for moderate to severe Alzheimer's that works differently from cholinesterase inhibitors. It's sometimes prescribed alongside them.

Mild Cognitive Impairment (MCI)

Noticeable memory or thinking changes that are more than typical aging but don't yet significantly interfere with daily independence. Some people with MCI go on to develop Alzheimer's; others stay stable or even improve. It's a stage worth monitoring closely with a doctor.

N

Neurodegeneration

The gradual loss of structure or function of brain cells, eventually leading to their death. It's the broad process underlying Alzheimer's and many other brain diseases.

P

PET scan (amyloid PET)

A brain imaging scan that can detect amyloid plaques directly in a living person's brain, using a special tracer. It's mainly used in research and specialist diagnosis, not routine screening.

Power of attorney

A legal document that lets a person name someone else to make decisions — financial, medical, or both — on their behalf. Best set up early, while the person with Alzheimer's can still participate in the decision.

R

Respite care

Short-term care that gives a family caregiver a planned break — anything from a few hours to a few weeks. It's a tool for preventing caregiver burnout, not a last resort.

S

Sundowning

A pattern of increased confusion, agitation, or restlessness in the late afternoon and evening, common in people with Alzheimer's. The exact cause isn't fully understood, but routine and light exposure can sometimes help.

T

Tau tangles

Twisted fibers of a protein called tau that build up inside brain cells in Alzheimer's disease, disrupting how the cells function. Along with amyloid plaques, they're one of the two hallmark brain changes in Alzheimer's.

V

Vascular dementia

Dementia caused by reduced blood flow to the brain, often after a stroke or from ongoing small-vessel damage. It's the second most common cause of dementia after Alzheimer's, and the two can occur together.

W

Wandering

When a person with dementia walks off and becomes lost or disoriented, even in familiar places. It's common and can be dangerous, so many families use ID bracelets, door alarms, or location devices as safeguards.