Several recent studies have promised a reliable test to detect Alzheimer’s disease in people with mild memory loss. What are these and should you request one?
One test is a very expensive imaging test, a specialized PET scan that will almost certainly not be covered by your insurance and is probably still best used in the research phase.
The other is a blood test – “phosphorylated tau” should you wish to Google it – that was reported to have over 90% accuracy in predicting Alzheimer’s in a group of elderly people (average age 74) who had either subjective memory loss, doctor-diagnosed mild cognitive impairment, or dementia.
The blood test was better than both primary-care physicians and dementia specialists in diagnosing Alzheimer’s disease and will probably soon be clinically available.
The real question, should the test be positive is: what next?
The medicines available to treat Alzheimer’s are not miracles. Both the older oral medicines and the newer IV medicines slow down the progression of the disease but do not cure it.
Considerable media attention and soaring stock prices have greeted the newer IV agents, but their results are only mildly better clinically than the old ones, and their potential side effects are worrisome, including bleeding in the brain.
The British agency responsible for approving new drugs in the National Health Service just turned down Biogen’s drug, Leqembi, and its U.S. FDA approval has been controversial.
There is hope, but it is yet unproven, that starting these drugs much earlier in the process might make them more effective. Hopefully clinical trials will be conducted to see if this is true.
My strong feeling is that, for most people, the side effects of the newer drugs outweigh their proven benefits.
Any medical test should only be done when knowing the results of the test is expected to have a beneficial effect on your health.
So, putting the horse in front of the cart, if you are worried about memory loss, have a full discussion with a doctor you trust. Ask what would happen after a positive test before you are tested. Then you can make an informed decision.
Edward Hoffer MD is Associate Professor of Medicine, part-time, at Harvard.
What Does The Doctor Say?
By Dr. Edward Hoffer