Dementia

Senior man with Alzheimer's disease putting shoe in microwave oven.
Senior Woman Comforting Man With Dementia At Home

Dementia is an overall term for diseases and conditions characterized by a decline in memory, language, problem-solving and other thinking skills that affect a person’s ability to perform everyday activities. Memory loss is an example. Alzheimer’s is the most common cause of dementia.

Dementia is not a single disease; it’s an overall term — like heart disease — that covers a wide range of specific medical conditions, including Alzheimer’s disease. Disorders grouped under the general term “dementia” are caused by abnormal brain changes. These changes trigger a decline in thinking skills, also known as cognitive abilities, severe enough to impair daily life and independent function. They also affect behavior, feelings and relationships.

Alzheimer’s disease accounts for 60 to 80 percent of cases. Vascular dementia, which occurs because of microscopic bleeding and blood vessel blockage in the brain, is the second most common cause. But there are many other conditions that can cause symptoms of memory loss and thinking disorders, including some that are reversible, such as thyroid problems and vitamin deficiencies.

Dementia is often incorrectly referred to as “senility” or “senile dementia,” which reflects the formerly widespread but incorrect belief that serious mental decline is a normal part of aging.

Symptoms of dementia can vary greatly. Examples include:

  • problems with short-term memory
  • keeping track of a purse or wallet
  • paying bills
  • planning and preparing meals
  • remembering appointments
  • traveling out of the neighborhood.

Many of the conditions are progressive, meaning symptoms start out slowly and gradually get worse.

Dementia is caused by damage to brain cells. This damage interferes with the ability of brain cells to communicate with each other. When brain cells cannot communicate normally, thinking, behavior and feelings can be affected.

The brain has many distinct regions, each of which is responsible for different functions (for example, memory, judgment and movement). When cells in a particular region are damaged, that region cannot carry out its functions normally.

Different types of dementia are associated with particular types of brain cell damage in particular regions of the brain. For example, in Alzheimer’s disease, high levels of certain proteins inside and outside brain cells make it hard for brain cells to stay healthy and to communicate with each other. The brain region called the hippocampus is the center of learning and memory in the brain, and the brain cells in this region are often the first to be damaged. That’s why memory loss is often one of the earliest symptoms of Alzheimer’s.

While most changes in the brain that cause thinking disorders are permanent and worsen over time, thought and memory problems caused by the following conditions may improve when the condition is treated or addressed:

  • Depression
  • Medication side effects
  • Excess use of alcohol
  • Thyroid problems
  • Vitamin deficiencies