Experts modify Alzheimer’s diagnosis – 07/17/2023 – Health

Experts in Alzheimer’s disease are proposing a change in the way doctors diagnose patients with the progressive brain disorder — the most common type of dementia — by creating a seven-point rating scale based on a patient’s cognitive and biological changes.

The proposed guidelines, unveiled by experts on Sunday in a report released at an Alzheimer’s Association conference in Amsterdam, encompass a system of numerical stages that assess disease progression, similar to those used in cancer diagnoses. The use of terms such as mild, moderate and severe is also eliminated.

The draft guidelines are open for expert review and comment and will be revised later to reflect that opinion, according to an Alzheimer’s Association spokesperson.

The redesign — replacing 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 treatments that require confirmation of disease pathology before use.

The new system was designed to be more accurate and better reflect a person’s underlying illness, 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 of 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 drug Leqembi, approved by the Food and Drug Administration (FDA) this month, and Eli Lilly’s experimental drug, donanemab, which is now under FDA review.

“We’re really entering an era of much more personalized medicine, where we’re starting to understand that certain biomarkers are elevated to certain degrees in people at different stages,” said Maria Carrillo, chief scientific officer of the Alzheimer’s Association.

Under the new diagnostic approach, patients would receive a score of 1 to 7 based on the presence of abnormal disease biomarkers and the extent of cognitive changes. The system also adopts four biological stages classified as a, b, c and d. For example, stage 1a is when a person is completely asymptomatic but has abnormal biomarkers.

“Stage 1a is really the beginning of evidence that the person has the disease,” Jack said.

In stage 2, an individual may have abnormal biomarkers and very subtle changes in cognition or behavior. Stage 3 roughly equates 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 even includes a stage 0, for people who have genes that guarantee they will develop Alzheimer’s disease. This category includes people with Down syndrome, 75% of whom develop Alzheimer’s as adults.

Noting the new system’s similarity to cancer stages, Jack said, “There’s 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 use by clinicians in clinical practice, as many face the prospect, for the first time, of offering patients treatments that may slow the course of the disease, rather than just treating the symptoms.

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 tau, that result in the loss of neurons and their connections.

The 2018 guidelines, intended for use in research, incorporated existing technologies to detect Alzheimer’s proteins based on PET (positron emission tomography) scans of the brain and tests of cerebrospinal fluid, which were only accessible by lumbar puncture. These tests were expensive and not commonly used in standard medical practice.