PEOPLE often think of Alzheimer’s when they think of dementia.
It’s the most common type of dementia, accounting for 60-80 per cent of cases, with memory loss being a key symptom.
But researchers are now sounding the alarm about a little-known brain disorder that causes memory and thinking problems, similar to Alzheimer’s.
Limbic predominant age-related TDP-43 encephalopathy, also known as LATE, was identified by researchers back in 2019 and is a separate disease that can mimic the symptoms of Alzheimer’s.
Surprisingly, it’s a common condition in older adults and often occurs alongside Alzheimer’s.
It typically causes a slow decline in memory on its own, but when paired with Alzheimer’s, it’s been found to speed up the progression of symptoms.
In a recent study published in the Alzheimer’s Association journal Alzheimer’s & Dementia, researchers highlighted an urgent need for “objective criteria” to diagnose and determine the stage all forms of dementia, including LATE.
They noted the importance of developing specific criteria to distinguish between LATE and Alzheimer’s in order to identify patients with memory loss who don’t have Alzheimer’s and to help refine treatment approaches.
Alzheimer’s vs LATE
While the symptoms of LATE are similar to those of Alzheimer’s, there are a couple of differentiating features.
The Alzheimer’s Society lists three differences:
- LATE seems to affect individuals over the age of 80 years
- Progresses slower than Alzheimer’s disease
- Tends to only affect memory
Beyond memory loss, Alzheimer’s disease can impact various aspects of daily life beyond just recall of information.
[bc_video account_id=”5067014667001″ application_id=”” aspect_ratio=”16:9″ autoplay=”” caption=”Five simple tests that could indicate dementia” embed=”in-page” experience_id=”” height=”100%” language_detection=”” max_height=”360px” max_width=”640px” min_width=”0px” mute=”” padding_top=”56%” picture_in_picture=”” player_id=”default” playlist_id=”” playsinline=”” sizing=”responsive” video_id=”6365521889112″ video_ids=”” width=”640px”]It can:
- Affect a person’s ability to reason, make decisions, understand language, navigate spatial environments and manage emotions
- Cause mood swings
- Cause a person to exhibit changes in personality
- Lead to difficulty with daily activities
- Lead to behaviour- changes like wandering or aggression
In the study report, the researchers proposed preliminary guidelines for diagnosing LATE in more detail – when it’s the main cause of memory loss and cognitive decline or when it’s present alongside Alzheimer’s disease.
In the guidelines, LATE is characterised by progressive episodic memory loss, similar to Alzheimer’s, but with distinct features.
Memory loss in LATE involves difficulty recalling information after a delay, even with cues, while immediate memory remains relatively intact.
This is different from memory issues associated with poor attention, where both immediate and delayed recall are affected, but recognition memory is preserved.
It was also noted memory loss in LATE tends to progress more slowly, with the symptom dominating for at least two years before other cognitive issues occur.
And patients with LATE may show mild deficits in semantic memory, such as difficulty naming categories or recalling famous events.
But as the symptoms can overlap, the researchers recommended cognitive tests to distinguish LATE from Alzheimer’s.
To diagnose “probable” or “possible LATE”, the researchers recommended the use of imaging techniques to identify hippocampal atrophy – a reduction in the size of the hippocampus, a part of the brain that’s important for learning and memory.
In cases of LATE, this atrophy is more striking than in cases of Alzheimer’s at a similar stage of memory impairment.
If hippocampal atrophy is present but lacks additional supportive features, the researchers suggested it could be “possible” LATE.
As there are no specific biomarkers for LATE, “probable LATE” is diagnosed by ruling out Alzheimer’s using biomarkers like amyloid PET scans or cerebrospinal fluid tests.
If an Alzheimer’s test is negative it increases the likelihood of LATE.
What causes Alzheimer’s and LATE?
The key difference between Alzheimer’s and LATE is their cause.
Dementia occurs due to damage to cells in part of the brain known as the hippocampus.
In Alzheimer’s this damage can be caused by the build-up of toxic sticky proteins, tau and amyloid.
In LATE there is a build-up of another toxic protein, called TDP-43.
Dementia can also be mistaken for normal signs of ageing. Find out the difference between the two below…