Does forgetting a name or word mean that I have dementia? The number of cases of dementia in the U.S. is rising as baby boomers age, raising questions for boomers themselves and also for their families, caregivers and society. Dementia, which is not technically a disease but a term for impaired ability to think, remember or make decisions, is one of the most feared impairments of old age. Incidence increases dramatically as people move into their 90s. About 5% of those age 71 to 79 have dementia, and about 37% of those about 90 years old live with it. Older people may worry about their own loss of function as well as the cost and toll of caregiving for someone with dementia. A 2018 study estimated that the lifetime cost of care for a person with Alzheimer’s, the most common form of dementia, to be US$329,360. That figure, too, will no doubt rise, putting even more burdens on family, Medicare and Medicaid.