What Happens to the Brain in Alzheimer’s Disease?

Alzheimer’s disease is a progressive brain disorder that slowly affects memory, thinking, and behavior. What makes it particularly challenging is that the changes in the brain usually begin years before any symptoms occur. By the time memory loss or confusion is noticeable, significant damage has often already taken place. 

The first changes happen at the microscopic level. Abnormal protein deposits build up in the brain. Amyloid-beta proteins form sticky plaques between neurons, while tau proteins twist into angles inside the cells. These protein accumulations disrupt communication between neurons, leading to the eventual death of brain cells. 

The damage usually begins in the hippocampus, the region of the brain that is responsible for forming new memories, and gradually spreads to the cerebral cortex, which controls thinking, reasoning, and language. Over time, most areas of the brain are impacted. As brain cells die, the brain shrinks through a process called atrophy, while fluid-filled spaces inside the brain, called ventricles, expand. This physical change mirrors the progressive decline in cognitive and daily functions. 

Symptoms develop gradually. In the early stages, memory lapses and confusion are common. As the disease progresses, people may struggle to recognize familiar faces or complete simple everyday tasks. In the later stages, the ability to communicate, move, or even swallow can be lost, requiring full-time care. 

Alzheimer’s disease is more than just memory loss, it’s a wide variety of changes that physically alter the brain over time. Understanding these changes is essential for early detection and for developing treatments that may slow or stop its progression. The more we learn about what happens inside the brain, the closer we get to protecting it.