© Reuters. FILE PHOTO: Dr. Seth Gill points to evidence of Alzheimer’s disease in positron emission tomography scans at the Center for Alzheimer’s Research and Treatment (CART) at Brigham and Women’s Hospital in Boston, Massachusetts, US, March 30, 2023. REUTERS/Brian Snyder/File Image
By Julie Stenhuysen
(Reuters) – Alzheimer’s disease experts are revamping the way doctors diagnose patients with the progressive brain disorder — the most common type of dementia — by developing a seven-point rating scale based on a patient’s cognitive and biological changes.
The proposed guidelines, unveiled by experts Sunday in a report released at the Alzheimer’s Association conference in Amsterdam, adopt a numerical staging system for assessing disease progression similar to that used in diagnosing cancer. It also eliminates the use of terms such as mild, moderate, and severe.
The renewal — 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 blood and new therapies that require confirmation of the disease’s pathology before they can be used.
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 on Aging, part of the US government’s National Institutes of Health.
The change comes as doctors prepare to identify and treat patients with Eisai and Biogen’s (NASDAQ:) Leqembi drug, which won FDA approval this month, and Eli Lilly’s (NYSE::) experimental drug donanemab, which is now under FDA review. .
said Dr. Maria Carrillo, chief scientific officer of the Alzheimer’s Association.
Under the new diagnostic approach, patients will 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 stages arranged A, B, C, and D. For example, stage 1a is when a person is completely asymptomatic but has abnormal vital signs.
“Stage 1a is really the beginning of evidence that someone has the disease,” Jack said.
In stage two, the individual may have abnormal vital signs and very slight changes in cognition or behavior. Stage 3 is roughly equivalent to the present, 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 stage 0 for people who carry genes that guarantee they will develop Alzheimer’s disease. This category includes people with Down syndrome, 75% of whom develop Alzheimer’s disease as adults.
Noting the new system’s similarity to cancer stages, Jack said, “There’s no such thing as mild breast cancer. They’re digital stages.” Jack also noted that many other conditions can cause dementia but not all dementia is Alzheimer’s disease.
The proposed guidelines are for physicians to use in clinical practice as many face the prospect for the first time of offering patients therapies that can slow the course of disease, rather than simply treat symptoms.
The draft guidelines are open for expert review and comment and will be revised later to reflect this input, according to a spokesperson for the Alzheimer’s Society.
Alzheimer’s disease, which gradually destroys memory and thinking skills, is characterized by changes in the brain including beta-amyloid plaques and neurofibrillary tangles, or tangles, that lead to the loss of neurons and their connections.
The 2018 guidelines, which were intended for research use, included existing technologies for detecting Alzheimer’s proteins based on positron emission tomography (PET) scans of the brain and cerebrospinal fluid tests, which are only accessible by lumbar puncture. These tests were expensive and not commonly used in standard medical practice.