A little-known form of dementia that is often mistaken for Alzheimer’s disease now has a new name and specific diagnostic criteria.
The researchers call this limbic dominant amnesic neurodegenerative syndrome (LANS), and they hope that their work will make it easier for medical professionals to care for and counsel patients with various forms of memory loss.
LANS is A different set of brain changes Unlike Alzheimer’s disease, it tends to progress more slowly and have milder symptoms, primarily affecting people over the age of 80.
As with Alzheimer’s disease, a definitive diagnosis can only be made by autopsy.
To help people suffering from memory loss, Mayo Clinic neurologist Nick Corriveau Lecavalier and his colleagues, in collaboration with other institutions in the United States and Spain, have provided a formal framework for distinguishing LANS from Alzheimer’s disease.
“In our clinical studies, we see patients whose symptoms of memory loss appear to be similar to Alzheimer’s disease, but when we look at brain images and biomarkers, it’s clear that they do not have Alzheimer’s disease.” To tell Senior author and Mayo neurologist David Jones;
“Before now we didn’t have a specific medical diagnosis that we could point to, but now we can provide some answers.”
A more accurate diagnosis would take into account factors such as age, severity of memory loss, brain scans and biomarkers.
In trials, the new diagnostic criteria successfully classified dozens of patients who died of Alzheimer’s disease or LANS based solely on their premortem health data. While the success rate was not perfect, it was more than 70 percent accurate.
Ultimately, the clinical criteria for LANS are likely related to brain changes caused by: Age-related TDP-43 encephalopathy with predominantly limbic system – Also known as LATE.
In this study, most patients with late brain changes had the highest scores for the LANS diagnosis, but the authors Note While the two terms are “very related,” LANS can technically cover any form of dementia that leads to degeneration of the limbic system.
LATE brain changes are highly common in older people, occurring in approximately 40% of autopsies of brains from people over the age of 85. It is characterized by the accumulation of a protein called TP-43 in the limbic system, a brain network involved in regulating memory, emotion and behavior.
These brain changes are clearly different from the tau protein tangles that occur in Alzheimer’s disease and tend to accumulate in parts of the brain involved in spatial cognition and reasoning.
2019, International Agreement report Recommendation Late brain changes should become part of the dementia classification system.
Alzheimer’s disease and LANS are often confused because there is a large overlap in symptoms. To complicate things further, LANS can occur at the same time as Alzheimer’s disease.
However, the two diseases are separate.
Mayo Clinic researchers reviewed available research on both types of dementia and identified key clinical differences between how LANS and Alzheimer’s disease present in patients.
Patients with LANS tend to suffer initially from episodic memory loss, which reduces their ability to recall details of situations, names of objects and people, and verbal fluency, but their visuospatial processing abilities are relatively preserved compared to patients with Alzheimer’s disease.
Furthermore, MRI studies suggest that in Alzheimer’s disease, volumetric loss tends to be concentrated in the neocortex, whereas loss of hippocampal volume is more associated with LANS.
LANS appears to progress more slowly and have milder effects than the rapid rate of decline seen in Alzheimer’s disease and the even more rapid rate of decline seen in people with both LANS and dementia. and Alzheimer’s disease.
“One example of a potential source of clinical challenge is limbic variant Alzheimer’s disease, in which tau is primarily localized in the limbic system and is the target of LANS,” the authors write. explain.
“By combining the advanced LANS criteria with visual assessment of tau,Pets It helps identify the pathology most likely to cause clinical symptoms.”
Unravelling the various forms and mechanisms of dementia is clearly a difficult task, but the Mayo team plans to continue refining the LANS classification.
This study Brain communication.
