Failing memory is a serious concern as we grow older. While medical solutions for memory loss remain elusive, diet, exercise, socialization and lifelong learning can push back cognitive impairment.

What is dementia? It refers to memory loss and other cognitive problems that are severe enough to interrupt a person’s daily life. Alzheimer’s, vascular dementia, and dementia with Lewy bodies are all types of dementia.

More than 5 million Americans currently live with Alzheimer’s disease—the most common form of dementia. By 2050, that number is expected to rise to 16 million Americans.

In Alzheimer’s disease, abnormal proteins called tau and beta-amyloid clump together to form deposits in the brain. These deposits gradually damage nerve cells and destroy areas of the brain. Vascular dementia often occurs after a stroke that damages blood vessels in the brain. The damaged vessels prevent enough blood from reaching brain tissues. People who have dementia with Lewy bodies have an abnormal buildup of a protein called alpha-synuclein in the brain. It’s possible to have a combination of these different dementia types, known as “mixed dementia.”

Dementia symptoms vary by type, but can include difficulty remembering names and events, trouble communicating, depression, poor judgment, confusion, behavior changes, and sleep disturbances. People who are suspected of having dementia will undergo a series of dementia tests, or Alzheimer’s tests, to determine whether they have lost memory and cognitive function. Doctors will ask the person and his or her family members about any memory problems and trouble completing daily activities.

Other tests involve evaluating memory, attention, problem-solving, and language skills. During these tests, the health care provider will ask the person a series of questions and assign tasks, such as remembering the names of common objects or drawing a face of a clock. Brain scans such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) may also be done to assess brain structure and function.