Pam Belluck in The New York Times:
“Has the person become agitated, aggressive, irritable, or temperamental?” the questionnaire asks. “Does she/he have unrealistic beliefs about her/his power, wealth or skills?” Or maybe another kind of personality change has happened: “Does she/he no longer care about anything?” If the answer is yes to one of these questions — or others on a new checklist — and the personality or behavior change has lasted for months, it could indicate a very early stage of dementia, according to a group of neuropsychiatrists and Alzheimer’s experts. They are proposing the creation of a new diagnosis: mild behavioral impairment. The idea is to recognize and measure something that some experts say is often overlooked: Sharp changes in mood and behavior may precede the memory and thinking problems of dementia.
…Dr. Zahinoor Ismail, a neuropsychiatrist at the University of Calgary and member of the group proposing the new diagnosis, said studies and anecdotes suggested that emotional and behavioral changes were “a stealth symptom,” part of the dementia disease process, not separate from it. Whatever is eroding memory and thinking skills in the dementia process may also affect the brain’s systems of emotional regulation and self-control, he said. If two people have mild cognitive impairment, the one with mood or behavior changes develops full-blown dementia faster, he said. Alzheimer’s patients with those symptoms “do much worse over time;” after death, autopsies have shown they had more brain damage. Of course, not everyone experiencing mood swings with age is suffering warning signs of dementia. Dr. Ismail emphasized that, to be considered M.B.I., a symptom should have lasted for at least six months and be “not just a blip in behavior, but a fundamental change.” Still, some experts worry that naming and screening for such an early-stage syndrome might end up categorizing large numbers of people, making some concerned they will develop Alzheimer’s when there are not yet effective treatments for the disease.