Millions of American women have routine mammograms and colonoscopies to detect breast and colorectal cancer early, when they're most treatable. So why don't they also get periodically tested for memory loss or a decline in thinking skills? The April 2014 issue of the Harvard Women's Health Watch explores and explains the recent U.S. Preventive Services Task Force recommendation against screening for Alzheimer's disease and other types of dementia.
"Screening" means testing a seemingly healthy person for signs of a hidden disease, like Alzheimer's or cancer. After conducting a thorough review of the evidence, the task force said that there isn't enough solid evidence to recommend screening for dementia, especially since not enough is known about the benefits and the harms of screening.
Why is early testing for Alzheimer's and dementia not recommended when early testing for diseases like breast cancer is recommended? In part, it has to do with treatment. While there are effective treatments for cancer, such as chemotherapy, radiation, and surgery, so far there aren't any truly effective approaches to stop the progression of dementia. While some medications can slow the progress of Alzheimer's disease, their side effects can be damaging.
"There are certain diseases in which we know that early detection can lead to early intervention, which can stave off worse outcomes, but if you don't have any kind of disease-modifying therapy at hand, it doesn't make a whole lot of sense to screen people who don't have symptoms," explains Dr. Aaron Philip Nelson, assistant professor of psychology at Harvard Medical School and author of The Harvard Medical School Guide to Achieving Optimal Memory.
One gene test that's available is for a rare type of Alzheimer's disease known as familial early-onset Alzheimer's disease. It accounts for less than 5% of total cases, and typically starts before middle age. A test also exists for ApoE4, an Alzheimer's risk gene. But it can't tell whether a person who carries the gene will actually develop Alzheimer's disease. Also of questionable merit are the do-it-yourself tests for dementia that are marketed directly to consumers. The Alzheimer's Association doesn't recommend these tests because they don't provide an adequate assessment risk.
Even getting a brain scan to look for the clumps of protein known as amyloid plaques that are characteristic of Alzheimer's disease can't accurately predict a future diagnosis.
While testing for hidden dementia in people without any symptoms doesn't make sense, those with worrisome changes in memory or thinking skills should consider visiting a geriatrician, neurologist, or neuropsychologist, who can test for these problems and offer options to those who have them.
Read the full-length article: "Should you be tested for dementia?"