Daughter and mother having a discussion © Dan Moore, E+, Getty Images (Daughter and mother having a discussion © Dan Moore, E+, Getty Images)

A friend lives thousands of miles from his mother, but he knows something is wrong.

She's repeating herself, asking a question or telling a story two or even three times in the same conversation. She used to be decisive; now she hems and haws about where the family will celebrate Christmas or when she'll visit her grandchildren. She's been having minor traffic accidents, a sign that her depth perception is faulty -- another potential sign of dementia.

But his mom gets defensive when he expresses concern. His dad blows him off when he suggests taking her to the doctor. Even his siblings, who to varying degrees acknowledge there's an issue, insist their mother is basically fine.

That's all pretty common when families are dealing with the early stages of any illness, but particularly dementia, said Carolyn McClanahan, a physician who became a financial planner and who specializes in end-of-life issues.

"Nobody wants to admit they can't live independently anymore," said McClanahan, director of financial planning for Life Planning Partners in Jacksonville, Fla. Denial is common in family members, too, because acknowledging what's happening can be too painful and frightening.

Denial can come at huge cost:

  • The person with symptoms could be suffering another, resolvable issue, such as a reaction to medication, a vitamin deficiency or an infection.
  • Even if she does have Alzheimer's, early detection permits treatment with medications that can allow her to remain independent longer.
  • Delay can prevent the person from making her wishes about future treatment known, putting another burden on the family. It can rob her of the opportunity to make important financial and legal plans, including protecting her assets and designating someone to make decisions for her when she no longer can.
  • Speaking of money, people with dementia are more vulnerable to scams, and their poor judgment that can leave them financially devastated. They may give away too much money or make bad investment decisions.

Image: Liz Weston

Liz Weston

"Elderly men are the worst . . . for getting the wool pulled over their eyes," particularly with investment scams and schemes, McClanahan said. But women are vulnerable too. McClanahan has one elderly client with dementia who needs to be protected from a manipulative, money-hungry daughter.

Making a bad financial decision isn't always a sign of dementia, of course. Our ability to make good financial choices tends to peak in our late 40s and early 50s, sliding gradually downhill from there, according to research by Federal Reserve economist Sumit Agarwal. So older people in general are more vulnerable to scams and questionable investment pitches than they were in middle age.

It's a matter of degree. The occasional financial mistake may not indicate a problem, but messing up repeatedly or in big ways known – giving donations she can't afford or offering sensitive financial information such as bank account numbers to a telemarketer – may be a sign of dementia.

Sometimes the line between normal age-related memory issues and incipient dementia can seem blurry, but the Alzheimer's Association offers helpful tips for discerning the difference:

  • Forgetting a word now and then is a normal part of aging. What's not: using made-up names, such as calling a watch a "hand clock," or having difficulty carrying on a conversation. Kelley Mercurio of Washington, Pa., said one sign of her grandfather's early Alzheimer's was that he got quiet. Avoiding conversation is one way people may try to disguise their inability to keep up.
  • Getting confused about the day of the week? That can be normal aging, if the person figures it out later. Likewise, misplacing things isn't a cause of concern if the person eventually can retrace her steps to find what she's lost. But if she can't figure out where she mislaid her keys or what day or season it is, there may be a problem.
  • Becoming more set in our ways can be a typical part of aging, and we may get irritated if our routines are disrupted. Big personality or mood changes, however, usually aren't normal. If someone becomes anxious, easily upset, defensive or suspicious when he didn't used to be, dementia may be the cause.

"The more angry they get, the more worried you should be," said Amy Florian, CEO of Corgenius, a Chicago-area company that trains advisers and other professionals how to help clients deal with transition and loss. "Anger is often a cover emotion for fear and embarrassment. If the family member is wondering about themselves, that can come out as anger."

One method to short-circuit their fury and get them to see a doctor is to mention the many non-dementia causes of memory problems -- and perhaps add a little social pressure.

"You might say, 'Mom, it might be nothing. Maybe you need a shot of vitamin B12 and it will all go away,'" Florian said. "'You don't want your friends to accuse you of having dementia and you don't.'"

If the diagnosis is dementia, you may still have time to prepare for the storm ahead. The tasks that need to be done include:

  • Drafting powers of attorney and other documents for dealing with incapacity.
  • Creating wills and other estate plans.
  • Discussing what kinds of care she does and doesn't want. The Five Wishes document and the POLST.org site may be helpful.
  • Figuring out how to pay for care. A financial planner and an elder-law attorney may be helpful.
  • Finding all the paperwork you may need, such as life insurance or military service records, while she can still remember where it is.

You may also want to record family stories and personal reminiscences, Florian said. Since short-term memories disappear first, you can ask mom about recent vacations and family events, then work back to her earlier memories. You can write down the stories or record them on video.

Not only will this help preserve family history, Florian said, but it will help you have conversations with her as her memory fades and all that remains are her earliest recollections.

"People learn things about their parents that they never knew," Florian said. "It's comforting to the patient when they can talk about their memories with someone."

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Liz Weston is the Web's most-read personal-finance writer. She is the author of several books, most recently "The 10 Commandments of Money: Survive and Thrive in the New Economy" (find it on Bing). Weston's award-winning columns appear every Monday and Thursday, exclusively on MSN Money. Join the conversation and send in your financial questions on Liz Weston's Facebook fan page.