At Last: A Reliable Diagnostic for Alzheimers

By Shlomo Maital

       Can Alezheimer’s (a form of dementia, caused by plaque that gums up the brain’s neurons and interconnections) be diagnosed early – before even symptoms appear?

        So far, the only diagnostics are PET scans or invasive spinal taps – not really practical. And those are accurate only 73 % of the time.   Primary care doctors?  Their early-onset diagnoses are accurate only 61% of the time.  So basically, at present, there is no practical accurate tool for diagnosing Alzheimer’s pre-symptoms.

        Do we really need an accurate diagnostic?  If there is no proven treatment – what good is it?  Just ruins the rest of a person’s life?!

          Personally – and many disagree – I would want to know.  It helps plan the remainder of life, including before symptoms become highly impairing.  And to make careful plans for care when symptoms become badly impairing. 

          Pam Belluck, writing in the New York Times *,  reports that a blood test developed in Sweden diagnoses Alzheimer’s 90% of the time.  The study was pubishing in the prestigious Journal of the American Medical Association.

*   P. Belluck. NewYork Times, July 28, 2024.

        A Swedish doctor, Dr. Oskar Hansson, said, “if you detect Alzheimer’s in the person without cognitive impairment, there’s no therapies to offer.”   So he does not recommend it. 

       How does the blood test work?  It focuses on a protein, called tau, that sprouts into tangles in the brain – a protein called ptau-217.   The blood test’s accuracy was highest with patients in a pre-dementia stage called mild cognitive impairment,  but it was not very accurate with the earliest stage, subjective cognitive decline, when ptients begin to perceive their memory is failing. (Hey – what senior does NOT perceive this?!).  Many people with subjective perceived cognitive decline do NOT in fact have Alzheimer’s.  And at this stage, the amount of the tau protein is likely very small.

         I think the main virtue of this test is to help screen candidates for Stage 1,2 and 3 clinical trials of Alzheimer’s drugs that combat the amyloid plaque in our brains.  Catching it early before the plaque does damage is vital.  Finding such subjects can be greatly helped by this Swedish test.