"This research creates a precise framework that other medical professionals can use to care for their patients. It has major implications for treatment decisions, including amyloid-lowering drugs and new clinical trials, and counseling on their prognosis, genetics, and other factors," said senior author of the study, David T. Jones, M.D., a Mayo Clinic neurologist, in a press release.
Although Limbic-predominant Amnestic Neurodegenerative Syndrome (LANS) is often mistaken for Alzheimer's disease, it differs in some important ways. Unlike Alzheimer's, LANS symptoms are restricted to memory loss and don't involve other areas. The disease is also known to progress more slowly than Alzheimer's, and has a better prognosis. Until now, doctors could only confirm the presence of LANS via a post-mortem brain tissue analysis.
In the current article, researchers drafted criteria for diagnosing LANS after analyzing data from over 200 participants in databases for the Mayo Clinic Alzheimer's Disease Research Center, the Mayo Clinic Study of Aging and the Alzheimer's Disease Neuroimaging Initiative. The criteria include being aged 75 and older, mild clinical syndrome, disproportionate hippocampal atrophy, impaired semantic memory, limbic hypometabolism, absence of neocortical degeneration, and a low likelihood of neocortical tau.
The researchers noted that LANS is related to limbic-predominant age-related TDP-43 encephalopathy (LATE) and other conditions. LATE, also known as LATE-NC (neuropathological change), was identified in 2019 and is characterized by a buildup of a protein called TDP-43 in the limbic system. Although LANS and LATE are related, they're not the same condition. While most patients with LANS have LATE, some with LANS may have Alzheimer's disease or other conditions. Whereas LANS can be diagnosed in living patients, LATE can only be determined after death.
"This study is retrospective in nature. The implementation of the LANS criteria in clinical settings and prospective studies are needed to further validate and refine this set of criteria," wrote the researchers in their paper.
They also noted that prospective studies are needed to further examine the value of the LANS criteria in predicting underlying disease driving limbic as opposed to neocortical degeneration.
Sources: Neuroscience News, Brain Communications, Medpage Today, Psychiatrist.com