Do you know someone who has dementia?

Dementia is not a specific disease, but a syndrome, a group of symptoms, that according to the National Institute on Aging cause "the loss of cognitive functioning—thinking, remembering and reasoning—and behavioral abilities to such an extent that it interferes with a person's daily life and activities." Alzheimer's is the most common type of dementia. Others include vascular dementia and dementia with Lewy bodies.

Sandra Day O'Connor, the first woman to sit on the U.S. Supreme Court, revealed in an open letter this week that she has been diagnosed with "the beginning stages of dementia, probably Alzheimer's disease."

"Memory problems are common among older adults, but dementia is different, it affects the ability to carry out everyday tasks, " says Dr. Jorge Camilo Mora, director of geriatric medical education at Herbert Wertheim College of Medicine. "We know age is a risk factor for dementia. The older we are, the higher our risk."

O'Connor is 88. She retired from the court in 2005 so she could spend more time with her husband who had been diagnosed with Alzheimer's; he died four years later. She has since been an advocate for patients and caregivers—and, in 2008, lobbied Congress to fund research.

Nearly 6 million Americans have Alzheimer's disease. It is the 6th leading cause of death in the United States. Additionally, it takes a devastating emotional and financial toll on more than 16 million caregivers.

Scientists are still trying to pinpoint the cause of Alzheimer's. There is no known cure.

Mora says early diagnosis is important because "exercise, diet modification and medication can help improve cognitive function and slow down progression."

Early warning signs

According to Mora, these are common early signs of loss in cognitive functioning. If you notice them in yourself or a loved one, consult a doctor for a full evaluation.

• Memory lapses— may repeat themselves often
• Mood or personality changes—may become aggressive or introverted/extroverted, start over-spending
• Careless accidents
• Confusion— misplaces things, confuses medications
• Anxiety and phobias—fear of being around other people or public places