When dementia is discussed, Alzheimer’s usually takes center stage. However, researchers are now sounding the alarm about LATE, a little-known memory loss condition that closely resembles Alzheimer’s but requires its own spotlight.
In a recent study published in the Alzheimer’s Association journal Alzheimer’s & Dementia, researchers highlight the urgent need for “objective criteria” to diagnose and stage all forms of dementia, including LATE.
Limbic predominant age-related TDP-43 encephalopathy (LATE-NC) is a surprisingly common condition in older adults, often occurring alongside Alzheimer’s disease. LATE-NC typically causes a slow decline in memory on its own but when paired with Alzheimer’s, it speeds up the progression of symptoms.
The researchers also noted that since several anti-amyloid therapies for Alzheimer’s are emerging, it is important to develop specific criteria to distinguish between LATE-NC and Alzheimer’s, to identify patients with memory loss who don’t have Alzheimer’s, and to refine treatment approaches accordingly.
In the study report, the researchers proposed preliminary guidelines for diagnosing LATE, particularly when it is the main cause of memory loss and cognitive decline or when it is present alongside Alzheimer’s disease, contributing to the overall symptoms.
As per the guidelines, LATE is characterized 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.
In contrast to Alzheimer’s, which often affects not just memory but other cognitive areas even in earlier stages, LATE tends to progress more slowly, with memory loss dominating for at least two years before other cognitive issues arise. Patients with LATE may also show mild deficits in semantic memory, such as difficulty naming categories or recalling famous events. However, since the symptoms could be overlapping, researchers recommend cognitive tests to distinguish LATE from Alzheimer’s.
To diagnose “probable” or “possible LATE”, researchers suggest the use of imaging techniques to identify hippocampal atrophy, a condition where the hippocampus of the brain, a region crucial for memory is shrunken or deteriorated. In LATE, this atrophy is often more pronounced than expected for Alzheimer’s at a similar stage of memory impairment.
If hippocampal atrophy is present but lacks additional supportive features, the researchers suggest that it could be considered “possible” LATE. Since 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. A negative Alzheimer’s test increases the likelihood of LATE.
