Memory Loss: What's Normal, What's Not

One challenge doctors have with diagnosing Alzheimer's disease is that memory loss can be caused by many medical conditions.

Depression and anxiety can cause us to forget things. So can what's called vascular dementia, caused by blockages in the brain's blood supply, or a metabolic problem, a stroke, even a brain tumor.

Yet people who age normally will continue to learn things -- their vocabulary will grow, and if they forgot someone's name, it should be a temporary slip of memory. As we get older, we may need more prodding or time to recall something, but our general fund of knowledge stays the same.

"The most common complaint of older adults is not remembering names," said Dr. Kaycee Sink, a geriatrician at Wake Forest University Baptist Medical Center.

"A normal adult will probably remember later, but someone who has memory impairment won't remember, period. A normal older adult may lose track of their nephew's wife's name, but knows it's their nephew's wife."

In Alzheimer's, memory loss is gradual, in a subtle way that families often shake off.

"It's not normal to repeat conversations you had an hour before," said Dr. Chip Celestino, a family doctor at Wake Forest University Baptist Medical Center specializing in geriatrics. "It's not normal to not recognize people you should recognize. It's not normal to not recognize where the store you've been many times is. It's not normal to not be able to shop, or not pay bills."

With Alzheimer's, the newest memories go first. Like bricks on a poorly built path, they aren't laid down securely -- or at all. The older memories are the next to crumble.

Then the memories that are the most firmly ingrained -- those of children, spouses, themselves -- fade.

"Sometimes the person with Alzheimer's doesn't remember what they don't remember," Sink said. "As the disease progresses, it's much harder on the families than the patients. They're losing someone they loved. This is not the same person they married."