Alzheimer disease
Alzheimer disease is a progressive brain disorder and the most common cause of dementia in older adults. It gradually damages memory, thinking, behavior, communication, independence, and daily function through complex changes in neurons, synapses, proteins, inflammation, and brain networks.
What Alzheimer disease is
Alzheimer disease is a progressive disorder that damages the brain over time. It is the most common cause of dementia, but dementia is the syndrome and Alzheimer disease is one cause. The disease can begin years before obvious symptoms, as brain changes accumulate and eventually affect memory, judgment, language, behavior, and independence.
Alzheimer disease and dementia
Dementia describes a decline in thinking, memory, or behavior severe enough to interfere with daily life. Alzheimer disease is one major cause, but dementia can also come from vascular disease, Lewy body disease, frontotemporal degeneration, Parkinson disease, brain injury, infections, alcohol-related damage, and other conditions. Correct diagnosis matters because care needs can differ.
Early symptoms
Early Alzheimer symptoms often include memory problems, especially difficulty remembering recent conversations, events, appointments, or where items were placed. Other early changes may involve trouble finding words, handling finances, planning tasks, navigating familiar places, repeating questions, or showing new anxiety, apathy, irritability, or social withdrawal.
Progression
As Alzheimer disease progresses, people may need more help with meals, medicines, hygiene, dressing, safety, and communication. Later stages can involve swallowing problems, infections, weight loss, mobility decline, sleep disruption, agitation, hallucinations, or loss of recognition. The course varies, and support needs change over time.
Brain changes
Alzheimer disease is associated with amyloid plaques outside neurons, tau tangles inside neurons, loss of synapses, inflammation, blood-vessel changes, and eventual brain shrinkage. These changes are not the whole story, and scientists still study how they interact. Some people have amyloid deposits without dementia, so biomarkers must be interpreted carefully.
Risk factors
Age is the strongest known risk factor for typical late-onset Alzheimer disease. Family history and genetics can matter, especially APOE variants and rare inherited mutations. Other factors linked to risk include cardiovascular health, diabetes, high blood pressure, hearing loss, depression, sleep problems, traumatic brain injury, social isolation, education, and physical activity. Risk is not destiny.
Diagnosis
Diagnosis usually combines history from the person and someone who knows them well, cognitive testing, physical and neurological exam, medication review, mental health assessment, and tests for other causes. Brain imaging, blood tests, spinal fluid tests, or PET scans may be used in some settings. New biomarker tools are changing diagnosis, but access and interpretation vary.
Treatment and care
There is no cure that restores lost brain function, but treatments and care can help. Medicines may temporarily support symptoms for some people, and newer disease-targeting therapies may be considered for selected early-stage patients under careful criteria. Equally important are exercise, sleep care, safety planning, routine, caregiver support, hearing and vision care, managing other illnesses, and reducing distress.
Caregiving and safety
Alzheimer disease affects families and care partners as well as the person with symptoms. Planning may involve driving, finances, medication management, home hazards, wandering risk, cooking safety, legal documents, respite care, communication strategies, and end-of-life preferences. Caregiver stress is real and needs support, not just advice.
Why it matters
Alzheimer disease matters because it changes identity, memory, independence, family life, and health systems. It is common, costly, and emotionally heavy, but not hopeless. Better understanding can reduce stigma, encourage earlier evaluation, improve support, and help readers follow research without mistaking every memory lapse for Alzheimer disease.