Brain scans can now help predict when dementia symptoms will surface

A new study from Neurology has found a completely accurate algorithm that can determine when dementia symptoms will set in based on just your age and one brain scan.H

A group of 236 people — average age 66 — were given amyloid PET scans over four years to examine the number of amyloid plaques in their brains. (Amyloid plaques are believed to cause the neural-cell die-out that results in dementia.) Only 12 of them were cognitively impaired at the start of the study. By the end of the study, 22 participants had developed dementia, and researchers saw it coming.

Scientists found that there is a tipping point in the brain for amyloid proteins at which you’re likely to start displaying cognitive symptoms of dementia. However, if the tipping point is reached earlier in life, like in your 50s, it’ll take longer to develop dementia (more than 20 years). If you reach the amyloid tipping point in your 80s, it’ll take less than 10 years for symptoms to develop.

The groundbreaking thing about this study is that the methods of predicting dementia were developed through a predictive algorithm, which was shown to be almost 100% accurate. Using only one amyloid PET scan and a patient’s age, scientists could determine not only when the amyloid build-up in your brain will reach the tipping point, but also when symptoms of dementia will begin to set in.

Amyloid PET scans

The amyloid PET scan, which searches the brain for amyloid plaque accumulation, is used often in Alzheimer’s research. Amyloid proteins, which are the main cause of Alzheimer’s, build up in the brain over decades to produce symptoms like forgetfulness, confusion, and an inability to think clearly.

While age is certainly the main risk factor for dementia, there’s also a genetic cause. Carriers of a gene called APOE4 are the most likely to develop dementia or Alzheimer’s. Around 25% of people carry one copy of this allele, but only 2% to 3% carry two copies. Having one copy doubles or triples your risk of developing Alzheimer’s, and having two copies makes your risk eight to 12 times higher than average.

But even if you have it, the Neurology study said that while you may reach the amyloid tipping point sooner than those without the gene, the trajectory of the disease remains the same for everyone after the tipping point is reached. The main determinant after you reach the tipping point is age — the younger you are when you reach it, the longer it takes to develop cognitive symptoms.

What to know about developing dementia

If you’re worried about developing dementia and begin to see symptoms, first, go to your doctor, as they’ll know your medical history and the immediate next steps to take. There are always things you can change to feel more cognitively aware, healthy, and spry, including your diet, exercise regimen, work schedule, and much more. But with something as serious as dementia, you don’t want to waste any time without professional medical advice, as it could alter the course of your treatment.

If you’re concerned about being genetically predisposed to dementia, the good news is that an APOE4 blood test can be produced through any bloodwork provider if ordered by your doctor. Research is still being done about the APOE4 gene, and the research shows that you are not at a substantial disadvantage if you reach the amyloid tipping point earlier in life than others. The predictive model in the study that illuminates how many years you have left until cognitive decline, however, isn’t so accessible.

If you’re a doctor, a math whiz, or a computer-science nerd, the algorithm is available in the study for anyone to utilize. It hasn’t yet been made into a comprehensible format for those without medical knowledge, and you’ll need an amyloid PET scan to establish a baseline of amyloid protein buildup. But it is possible to do the math yourself.

Additionally, if you’re seriously concerned about developing dementia, you can always volunteer for one of the many Alzheimer studies being done — so you can help the greater good while learning more about your health.