By Julie Steenhuysen
(RockedBuzz via Reuters) – Alzheimer’s disease experts are revamping the way doctors diagnose patients with progressive brain disorder – the most common type of dementia – by devising a seven-point rating scale based on cognitive and biological changes in the patient.
The proposed guidelines, unveiled by experts on Sunday in a report published at an Alzheimer’s Association conference in Amsterdam, embrace a numerical staging system that assesses disease progression similar to that used in cancer diagnoses. They also eliminate the use of terms such as mild, moderate and severe.
The revamp – which replaces guidelines issued in 2018 – was prompted by the increased availability of tests that detect key Alzheimer’s-related proteins such as beta-amyloid in the bloodstream and new treatments that require confirmation of the disease’s pathology before ‘use.
The new system is designed to be more accurate and better reflect a person’s underlying disease, according to Dr. Clifford Jack of the Mayo Clinic in Rochester, Minnesota, lead author of the report sponsored by the Alzheimer’s Association and the National Institute of Aging, a part of the US government’s National Institutes of Health.
The change comes as doctors are preparing to identify and treat patients with Eisai and Biogen’s drug Leqembi, which won Food and Drug Administration approval this month, and Eli Lilly’s experimental drug donanemab , which is now under FDA review.
‘We are really entering an era of much more personalized medicine, where we are starting to understand that there are certain biomarkers that are elevated to certain levels in people at different stages,’ said Dr Maria Carrillo, scientific director of the Alzheimer’s Association.
With the new diagnostic approach, patients would receive a score from 1 to 7 based on the presence of abnormal disease biomarkers and the extent of cognitive changes. The system also includes four biological phases classified a, b, c and d. For example, stage 1a is when a person is completely asymptomatic but has abnormal biomarkers.
“Phase 1a is really the beginning of proving that someone has the disease,” Jack said.
In stage 2, an individual may have abnormal biomarkers and very subtle changes in cognition or behavior. Stage 3 is approximately equivalent to the current presymptomatic stage known as mild cognitive impairment, while stages 4, 5 and 6 are equivalent to mild, moderate and severe dementia.
The new scale also includes a stage 0 for people who carry the genes that guarantee they will develop Alzheimer’s. This category includes people with Down syndrome, 75% of whom develop Alzheimer’s in adulthood.
Noting the new system’s similarity to cancer stages, Jack said, “There is no such thing as mild breast cancer. It’s numerical stages.” Jack also noted that many other conditions can cause dementia, but not all dementia is Alzheimer’s disease.
The proposed guidelines are intended for clinicians to use in clinical practice as many are facing the prospect of offering patients treatments that can slow the progression of the disease, rather than just treating symptoms, for the first time.
The draft guidelines are open to expert review and comment and will be revised later to reflect that input, according to an Alzheimer’s Association spokesperson.
Alzheimer’s, which gradually destroys memory and thinking skills, is characterized by changes in the brain including beta-amyloid plaques and neurofibrillary tangles, or tau, that cause neurons and their connections to lose.
The 2018 guidelines, intended for research, incorporated existing technologies to detect Alzheimer’s proteins based on PET scans of the brain and cerebrospinal fluid tests, which were only accessible via a lumbar puncture. Such tests were expensive and not typically used in standard medical practice.
(Reporting by Julie Steenhuysen in Chicago; Editing by Will Dunham)