LATE dementia: Why it's often missed - and why it matters
Recognized in recent years, this form of dementia often overlaps with Alzheimer's.
- Reviewed by Hyun-Sik Yang, MD, Contributor
In medicine, it's known that certain diseases are likely to occur together, like high blood pressure and diabetes. It turns out the same is true for dementia, which scientists have discovered is often driven by multiple distinct diseases. The most common of these is Alzheimer's. But recent years have brought a new addition to the list of possibilities: LATE.
It may be "late" to the field, but LATE (which stands for limbic-predominant age-related TDP-43 encephalopathy) is likely the third most frequent cause of dementia, after Alzheimer's and vascular dementia. Importantly, too, many people whose memory loss and other dementia symptoms might be blamed on Alzheimer's actually have LATE - or a combination of the two, says Dr. Hyun-Sik Yang, a neurologist at Harvard-affiliated Brigham and Women's Hospital.
"LATE dementia isn't some really rare disorder, but it's not been on most doctors' radar," he says. "It explains about 15% to 20% of dementia cases, so it's actually relatively common."
Comparing LATE and Alzheimer's
LATE dementia was widely recognized by experts in 2019 with its naming by Harvard neurologist Dr. Reisa Sperling, but the disease had attracted increasing research since the early 2000s. Prominent neurologists, including Dr. Sperling and Dr. Yang, published the first formal criteria in 2025 to help doctors spot LATE.
LATE and Alzheimer's share certain traits, and both are characterized by progressive memory loss. But when LATE dementia is the culprit, memory loss typically develops more slowly and is less severe. LATE also tends to appear in the "oldest old," people 80 and beyond.
"Only about 25% of LATE cases happen without the significant amyloid clumps or tau tangles typical of Alzheimer's," Dr. Yang says, referring to abnormal protein accumulations found in the brains of dementia patients at autopsy. "If LATE occurs alone, it acts like a less aggressive version of Alzheimer's, but people affected by both types show the fastest decline."
Tricky diagnosis
Unlike Alzheimer's, LATE dementia can't yet be definitively diagnosed while someone is alive. Alzheimer's can usually be identified through spinal fluid samples, MRI and PET scans, and more recently, blood tests for amyloid or tau. But confirming a LATE diagnosis requires a brain autopsy to spot clumps of a protein called TDP-43 that characterize the condition.
If tests show no evidence of Alzheimer's in someone who is experiencing progressive memory loss, the person likely has LATE, Dr. Yang says. It's still exceedingly challenging for doctors to determine, however, if someone has a combination of Alzheimer's and LATE.
Because scientists haven't yet zeroed in on a specific biomarker - a biological signal - they can target with a test, no promising therapies have yet been discovered for LATE, Dr. Yang notes.
"Research is just beginning, and we believe more breakthroughs will come down the road," he says. "But for now, there isn't a great understanding about why it happens or how to treat it."
Valuable insight
With both Alzheimer's and LATE currently incurable and causing overlapping symptoms, it may seem pointless to understand whether someone has LATE - but that's not the case, Dr. Yang says. The distinction matters because people with only LATE might not benefit from emerging Alzheimer's therapies that target amyloid or tau in the brain.
In addition, "it can guide doctors to know the prognosis," he says. "If someone is 85, say, and has had progressive memory loss for many years, but tests for Alzheimer's show nothing, that means, on average, this person will progress slower. This is important to know."
The insight can also help patients and their loved ones understand what to expect. "For some patients, having a name for their disease is important to them, in addition to knowing the prognosis," Dr. Yang says.
Dr. Howard LeWine, chief medical editor of Harvard Health Publishing, agrees. "It will be very helpful for patients to understand they may have LATE, not only to give them some reassurance their memory loss is likely to be slower than Alzheimer's, but so they don't undergo therapies that probably won't be effective."
Habits that can help lower dementia riskThere's no silver bullet that guarantees we can avoid dementia, but these basic lifestyle habits can lower our risk. Regular exercise. Done on a consistent basis, activities such as walking, running, swimming, and cycling help by increasing blood flow to the brain, supporting blood vessels, and reducing inflammation. Resistance (strength) training can also help maintain memory, attention, and concentration. Healthy eating. Several diets are believed to promote brain health, all of which emphasize eating plenty of fruits, vegetables, and fish high in omega-3 fatty acids, while avoiding red meat and processed foods. Quality sleep. Our brains clear out harmful amyloid proteins while we sleep - a process disrupted by conditions such as insomnia, sleep apnea, or other frequent awakenings. |
Image: © Ekaterina Vasileva-Bagler/Getty Images
About the Author
Maureen Salamon, Executive Editor, Harvard Women's Health Watch
About the Reviewer
Hyun-Sik Yang, MD, Contributor
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