Alzheimer's brain changes may begin years before symptoms appear

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Early-onset Alzheimer's can appear as early as age 30

Drugs recently approved to slow the progression of Alzheimer's appear to work best when administered as early as possible. Early stages are marked by a low buildup of tau, a protein experts believe clumps into misfolded, neuron-disrupting tangles once clusters of another protein—amyloid beta—have already started causing damage.

Alzheimer's can cause brain shrinkage of between 10% and 30%

While the exact cause of Alzheimer's is debated, the buildup of amyloid plaques and tau protein tangles is instantly recognizable in post-mortem examinations. The atrophy of brain cells caused by this molecular pileup leads to noticeable physical changes, including significant shrinkage in affected brain regions.

Visualize the difference between a healthy brain and one with Alzheimer's

The brain has three main parts—the cerebrum, brain stem, and cerebellum—each combining to control the entirety of the body's operations. Alzheimer's progressively deteriorates the circuitry in these structures, resulting in what we see as the symptoms of the disease.

Five to ten percent of Alzheimer's cases are early-onset

Early-onset Alzheimer’s typically emerges around 40 to 50 years of age, with devastating effects. This video follows Brian, diagnosed with the disease at age 54, as he travels the country as an advocate for research and discusses the progressive mental fog of Alzheimer’s.

"Plaques" and "tangles" are top potential causes of Alzheimer's—but questions remain

The exact causes of Alzheimer's—and how to treat it—continue to be the subject of intense research. Two leading factors are amyloid beta plaques and tau protein tangles, which effectively pile up in the brain and interfere with neurons and cause cell death, which manifests as memory loss and other symptoms.

How neurodegeneration happens, the underlying disease process of dementia

Dementia symptoms may vary between individuals, and may include mood changes, difficulty walking, speaking, and memory problems. It can progress over many years, occurring due to progressive damage to nerve cells in the brain. This degradation may happen for myriad reasons, and its triggers are under investigation.

The first identification of Alzheimer's was made in 1906

The first case of Alzheimer's disease dates to the early 20th century when Dr. Alois Alzheimer had 51-year-old Auguste Deter as a patient. Deter struggled with sudden memory issues and aggressive, irrational behavior. After Deter's death, Alzheimer examined her brain and found strange collections of molecular pileups.

Genetic blood test offers an estimated clock on when Alzheimer's symptoms may appear

The 2026 research finding from researchers at Washington University School of Medicine in St. Louis—if validated in broader populations—suggests that an already available blood test could estimate when Alzheimer's symptoms may begin within a margin of several years. The test detects a protein called p-tau217 found in blood plasma and the researchers incorporated the findings from that blood test into a statistical model to come up with the symptom timeline predictions.

Scientists are reevaluating the causes of Alzheimer's beyond the amyloid hypothesis

The cause of Alzheimer's disease has been debated for decades. The amyloid cascade hypothesis—where plaques build up in the brain, triggering neurodegeneration—has long been the leading theory. But after a number of failed drug trials, researchers are beginning to reevaluate various culprits. [Untreated hearing loss is linked with dementia risk](https://www.thelancet.com/article/S0140-6736(20)30367-6/fulltext) Hearing loss does not cause dementia, but it does increase the risk of developing dementia and research suggests that people who wear hearing aids for age-related hearing loss also maintain better brain function than those who don't.

How aging degrades neural functioning in the brain over time

Aging affects the brain perhaps more than any other organ in the body. Throughout life, the brain experiences radical shifts in the number of neurons, synaptic connections between neurons, and hormone levels that regulate our mood and processing.

MS can damage the brain up to 7 years before symptoms appear

Recent research scouring blood samples from 134 people with MS, both before and after their diagnosis, found that about seven years before these patients were diagnosed, there was a spike in a protein called myelin oligodendrocyte glycoprotein—indicating disease-associated damage to the protective myelin around nerve fibers.

How frontotemporal dementia changes your personality

Significant changes in personality later in life are often attributed to psychological factors. But Dr. Bruce Miller, long-time researcher of FTD, argues this shift is most often attributable to changes in the brain.

An Alzheimer's patient discusses her condition with children

Alzheimer's is a deadly disease that profoundly changes a person's abilities and personality, which makes it difficult to explain to kids. Responding to potentially uncomfortable questions with honesty (and relatable imagery) about the costs and nature of the disease goes a long way in fostering understanding.

These areas of the brain are hard-hit in depression—but the changes are reversible

Depressed brains can have certain characteristic changes, including an overactive amygdala, reduced hippocampus size, and changes to the thalamus and neuromodulating chemicals in the brain.

1440: Everything you need to know about Alzheimer's

What is Alzheimer's, and is it different from dementia? In short, yes—Alzheimer's is a specific brain disease that falls under the umbrella of dementia. However it is the most prevalent form of the condition, accounting for 60 to 80% of reported dementia cases.

Poor sleep increases the risk of developing Alzheimer's

Brain imaging studies reveal poor sleep leads to production of amyloid beta proteins—molecules linked to Alzheimer’s—which are cleaned from the brain during high-quality sleep. These findings suggest conditions like sleep apnea and insomnia increase the risk of developing the disease.

Memory disorders disrupt the brain's ability to make, store, or recall memories

These disorders stem from reversible issues like vitamin deficiencies or irreversible causes such as stroke or dementia. Only one type of dementia—familial Alzheimer’s disease—is directly inherited and accounts for about 20% of Alzheimer’s cases.

Learn the differences between mild cognitive impairment and age-associated memory loss

Mild cognitive impairment is a condition in which people experience more thinking and memory problems than expected for their age. It's often associated with depression and anxiety. Daily routines, writing things down, and healthy lifestyle choices can help cope with the condition, but there's no cure. The condition elevates the risk of developing dementia and Alzheimer's.

How Alzheimer’s disease becomes fatal

Despite more than 100,000 people with Alzheimer's dying each year, the specific cause of death is not the disease itself. Often, secondary diseases arise from complications with the disease, including pneumonia, severe falls, malnutrition, or infection. Read more about the range of complications caused by Alzheimer’s here.

How Alzheimer's disease affected one family as symptoms progressed

News program 60 Minutes interviewed a couple navigating aging and Alzheimer's over a 10-year period to illustrate the effects of the disease on their lives.

Brain training game creates long-lasting changes in the brain that may help protect against dementia

Findings published in 2026 that tracked more than 2,000 older adults, examining dementia onset and completion of cognitive speed training activities, provide some of the strongest evidence yet that cognitive training games can help protect against dementia. Participants who underwent speed training and received booster sessions had a 25% reduction in the risk of dementia diagnosis compared with the control group.

Chronic drug use can cause neurological changes in the brain

Neuroscientist Judy Grisel breaks down the biology of addiction, examining how drugs hijack the brain’s natural reward system and create lasting neural changes. The physiological and neurological impacts of chronic drug use require a multifaceted treatment approach.

Schizophrenia symptoms, like psychosis, often first emerge among young adults

A combination of genetics, significant brain changes to the frontal cortex, and hormonal changes during young adulthood—late teens to early 30s—result in schizophrenic symptoms often showing up during this period. The stress of life changes at that age may also be a contributing factor.

A super-sniffer smelled her husband's Parkinson's disease years ahead of symptoms

She discovered she could smell diseases, including Parkinson's, tuberculosis, Alzheimer's, cancer, and diabetes. Working with an analytic chemist, she's learned she can smell subtle changes in odor—ones that smell consistent across individuals with the same disorder—even before symptoms manifest.

Cryptococcus neoformans, a growing threat, causes infections in the brain and lungs

This inhalable, microscopic pathogen is found worldwide. It rarely causes illness, but it can take root in those with compromised immune systems, including people with advanced HIV/AIDS. Symptoms of cryptococcal infection—such as a stiff neck, vomiting, and confusion—can begin weeks or months after breathing in spores, though sometimes symptoms won’t appear for years. There are no known cases of transmission between people or between people and animals.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Poison ivy will likely become both larger and more resilient due to climate change.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Walt Disney's early film 'Alice's Wonderland' was a groundbreaking innovation in the silent film era

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-2016.

Graffiti dates back to at least ancient Pompeii, where citizens scrawled messages to one another on public walls

Trace how the Bill of Rights, inspired by centuries of political theory, took shape between 1774 and 1789.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.