Frequent difficulty keeping track of details. Again, this is different from being flaky and distracted because you're trying to multitask. There's cause for concern, says Wilson, when several such lapses occur within a day, not just on occasion from week to week. A classic example of a potentially worrisome lapse: when a person having a conversation with his or her adult daughter, say, repeats the same story or details as if it had not yet been mentioned. An important point to note, of course, is that some older folks tell the same stories repeatedly when they're with friends and family, which may be a sign not of memory loss but of being fixed on a comforting memory from the past. Other such signals are forgetting dates, making mistakes with medications, or forgetting appointments, says Knopman.
Problems with reasoning or language. Trouble coming up with the right word, say, or problems orienting oneself geographically to get from point A to point B can be classic signs of issues with reasoning, Knopman says. As the disease process of dementia affects other areas of the cerebral cortex, including causing a loss of volume and atrophy, a person's ability to make reasoned decisions, to select the appropriate descriptive word, or to use landmarks and recruit skills to make use of directions will diminish.
Forgetting what an item or object is for. If a person looks at his checkbook and all of a sudden doesn't recall what it is or why it is used, that's a hint of cognitive trouble. "To not understand the meaning of an object," says Knopman, "we see that in some early types of dementia.
[Related: Here's how you can keep your brain fit.]