Understanding Dementia and Alzheimer’s Disease

What Is Dementia?

Dementia is a general term that describes a decline in cognitive abilities—such as memory, language, and problem-solving—that interferes with daily life. It is not a single disease, but a collection of symptoms caused by disorders affecting the brain. Alzheimer’s disease is the most common cause of dementia, responsible for 60–80% of cases.

Alzheimer’s Disease Explained

Alzheimer’s disease is a degenerative brain condition that leads to memory loss, changes in thinking and behavior, and eventually loss of the ability to carry out everyday tasks. It usually begins in the area of the brain associated with memory (the hippocampus), and symptoms worsen over time.

Types of Dementia

In addition to Alzheimer’s, other common types include:

• Vascular dementia – often caused by microscopic bleeding or blood vessel blockage in the brain.

• Lewy body dementia

• Frontotemporal dementia

• Mixed dementia – a combination of multiple types, such as Alzheimer's and vascular dementia.

Conditions That Mimic Dementia

Some conditions can cause memory and thinking issues but are not true dementia—and may be reversible. These include:

• Depression

• Medication side effects

• Alcohol misuse

• Thyroid issues

• Vitamin deficiencies

Symptoms and Warning Signs

Early symptoms can vary, but commonly include:

• Memory loss affecting daily life

• Difficulty planning or solving problems

• Confusion about time or place

• Trouble understanding visual images or spatial relationships

• Misplacing things and losing the ability to retrace steps

If you notice these symptoms in yourself or a loved one, see a doctor. Early diagnosis allows for better treatment options, participation in clinical trials, and time to plan for the future.

Diagnosing Dementia

There is no single test for dementia. Diagnosis involves:

• Reviewing medical history

• Physical and neurological exams

• Lab tests

• Cognitive and memory assessments

Specialists such as neurologists or geriatricians may be involved when the diagnosis is unclear or complex.

Causes of Dementia

Dementia results from damage to brain cells, which disrupts their ability to communicate. Different types of dementia involve different types of brain damage in specific regions. For example, in Alzheimer's, the buildup of abnormal proteins interferes with cell function and leads to cell death.

Support and Resources

A dementia diagnosis can be overwhelming, but you’re not alone. The Alzheimer’s Association offers a 24/7 Helpline (800.272.3900), caregiving resources, local support groups, and educational tools—including a free online course on understanding Alzheimer’s and dementia.