dementia

the Publication Manual of the American Psychological Association, 4th ed., says the term "dementia" is preferred to "senility." Senility denotes conditions brought on by aging, not dementia. Dementia is not a specific illness, but refers to a wide range of symptoms, and is “a general term for a decline in mental ability severe enough to interfere with daily life,” according to the Alzheimer’s Association. Alzheimer’s disease is the most common form of dementia, although there are others. Refer to someone as having dementia only if the information is relevant to the story and a licensed medical professional has formally diagnosed the person. And use people-first language, such as “a person with dementia." See also Alzheimer's disease, senility.