A little forgetfulness is perfectly normal as we age. But a lot of forgetfulness, or certain kinds of forgetfulness, are not. They could signify the early stages of Alzheimer’s disease, the most common form of dementia, affecting one in 20 people over age 65. Since memory loss occurs both in healthy people and in people who are developing Alzheimer’s, it’s important to know what’s normal and what’s not. And it’s far better to find out sooner rather than later, because if it is Alzheimer’s, early diagnosis and treatment may be able to help you maintain your memory as long as possible.