Just as not all forgetfulness signals dementia, not all dementia is a sign of Alzheimer’s disease. While 60 to 80 percent of dementia cases in the U.S. are Alzheimer’s, according to Dr. Adelman, the rest involve other forms, including vascular dementia (e.g., multiple strokes), frontotemporal lobe dementia, or FTL, which can cause disinhibition as well as cognitive decline in people as young as 40, and dementia with Lewy bodies.
Surprisingly, some patients with symptoms of dementia may not have dementia at all. Instead, the symptoms may be related to a treatable condition such as a thyroid disorder, a subdural hematoma (when blood pools outside the brain, usually caused by trauma), a metabolic problem like low blood sodium, normal pressure hydrocephalus or drug toxicity.
“Many things can trigger cognitive problems in an older person, including depression, certain medications, or various diseases,” says Dr. Adelman.
Indeed, according to a meta-analysis in the Archives of Internal Medicine, 9 percent of patients with dementia actually had some other, reversible condition. The rate of reversible dementias in those older than 65 is about 5 percent, according to a 2015 article in the Journal of Geriatric Mental Health. For those younger than 65, about 18 percent of cases with dementia symptoms involve reversible causes. That’s why it’s important to see a doctor for an evaluation as soon as possible if you notice a change in a loved one’s behavior, such as a normally outgoing, sharp person becoming withdrawn or confused.
The first step is getting a cognitive screening from a physician.
“Often, an older person has such excellent social skills that they can cover up their deficits,” says Dr. Adelman. “But we ask questions and do assessments with various tools that can gauge the quality of a person’s cognitive status.”
It helps for a loved one to come along to weigh in on any changes that may have been observed. The work-up likely will involve neuropsychological testing, imaging of the brain, and blood work.