Makiki, HAWAII - Everyone forgets things from time to time- the house keys, an acquaintance's name. But when it is a normal sign of aging and when is it a more serious problem like Alzheimer's? 

Sometimes, Makiki resident Tom Yoshida forgets where he puts things. "Keys, glasses, false teeth. You don't leave it where you need to on the washbasin, and you find it on your dresser," he says.

It happened enough that he finally asked his doctor about it. "In talking with the doctor I say, 'Is this normal?' They say, 'Yeah, but at 82 you're doing quite well.'"

Mild changes in memory are common as we age. Kaiser Permanente gerontolotist Dr. Serena Lo says forgetfulness isn't always a sign of dementia. She will question, "Are you depressed? Other issues going on? Distracted?"

It could be medication, or just normal aging. 

"For dementia, you have to have memory loss and loss of functions," clarifies Dr. Lo. Forgetting where you put the keys is normal. Forgetting how to perform daily tasks is not.

This is how it manifests at the medical clinic, says Dr. Lo: "People start missing appointments. They don't show. They don't order their medicines or take it correctly. These are big signs we see."

Other signs include not managing money well; forgetting to pay bills or sign the check before sending it. That, Dr. Lo explains, is a red flag. "They're starting to lose function in how they live."

That could be dementia. Dr. Lo says she can give screening tests that ask questions like, "What state are we in? What year is it? Get a sense. Do they know time?" 

But doctors also need someone to give perspective. "We need a family member, someone to tell us, 'Mom use to be like this, now she's not.' Dementia is still a diagnosis made by history," Dr. Lo adds.

Yoshida says he's OK. Regular exercise keeps him sharp. And a mindfulness about the world keeps his mind alert. "One of things that helps us is to be actively engaged in observing the people around you," says the retired Iolani School chaplain.

Check with your doctor if you think you have memory issues.