© Reuters. FILE PHOTO: Dr. Seth Gale shows evidence of Alzheimer’s disease on a PET scan at the Center for Alzheimer’s Research and Treatment (CART) at Brigham And Women’s Hospital in Boston, Massachusetts, U.S., March 30, 2023. REUTERS/ Brian Snyder/File Photo
By Julie Steenhuysen
(Reuters) – Alzheimer’s disease experts are improving 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 patients.
The proposed guidelines, revealed by experts on Sunday in a report issued at the Alzheimer’s Association conference in Amsterdam, include a numerical staging system that assesses disease progression similar to that used in cancer diagnosis. They also eliminated the use of terms such as mild, moderate and severe.
The overhaul – replacing guidelines issued in 2018 – is driven by increased availability of tests that detect key Alzheimer’s-related proteins such as beta amyloid in the blood and new treatments that require confirmation of disease 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 changes come as doctors prepare to identify and treat patients with Eisai and Biogen’s drug (NASDAQ:) Leqembi, which won Food and Drug Administration approval this month, and the experimental drug Donanema Eli Lilly (NYSE:), which is now under FDA review.
“We’re really entering a much more personalized era of medicine, where we’re starting to understand that there are certain biomarkers that are elevated to certain levels in people at different stages,” said Dr. Maria Carrillo, chief scientific officer for the Alzheimer’s Association.
Under the new diagnostic approach, patients will receive a score of 1 to 7 based on the presence of abnormal disease biomarkers and the degree of cognitive change. The system also includes four biological stages rated a, b, c and d. For example, Stage 1a is when a person is completely asymptomatic but has abnormal biomarkers.
“Stage 1a is really early evidence that someone has the disease,” says Jack.
In Stage 2, a person may have abnormal biomarkers and very subtle changes in cognition or behavior. Stage 3 is roughly equivalent to the presymptomatic stage currently 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 the gene that guarantees they will develop Alzheimer’s. This category includes people with Down syndrome, 75% of whom develop Alzheimer’s as adults.
Noting the new system’s similarities to cancer staging, Jack said, “There’s no such thing as mild breast cancer. It’s a numerical staging.” 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 face the prospect of offering patients for the first time treatments that can slow the course of disease, rather than simply treat symptoms.
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, or tau, kinks that result in loss of neurons and their connections.
The 2018 guidelines, which are intended for research use, incorporate existing technologies for detecting Alzheimer’s proteins based on PET scans of the brain and cerebrospinal fluid tests, which are only accessible via lumbar puncture. Such tests are expensive and usually not used in standard medical practice.