- Other types of dementia and cognitive impairment are often misdiagnosed as Alzheimer’s disease.
- Researchers have identified another disease that causes memory loss, called limbic-predominant amnestic neurodegenerative syndrome (ANS), which is often misdiagnosed as Alzheimer’s disease.
- Scientists have developed new criteria to help doctors better diagnose the disease.
Although Alzheimer’s disease is the
The same is true for other age-related neurological disorders, such as mild cognitive impairment.
Mayo Clinic scientists have identified another memory disorder in older adults that is often misdiagnosed as Alzheimer’s disease. The researchers have developed new criteria to help doctors diagnose the condition, called limbic-predominant amnestic neurodegenerative syndrome (ANS).
The study was recently published in the journal Brain communications.
According to Dr. David T. Jones, a neurologist at the Mayo Clinic and lead author of the study, LANS is a progressive degenerative disease of the body’s limbic system — a brain system important for memory — with a variety of underlying causes.
“When this system degenerates, it becomes difficult for people to form new memories, often leading to difficulty remembering recent events, repeating statements that have already been said, and remembering names,” Jones said. Today’s Medical News.
Traditionally, Jones said, it has been difficult for doctors to diagnose someone with LANS because memory problems like those seen in LANS are not very specific.
“Many nondegenerative diseases can cause memory impairment, and degenerative diseases that affect nonlimbic brain regions also produce symptoms of memory loss,” he continued. “The use of brain imaging and other biomarkers is needed to be sure that a patient’s symptoms are from isolated limbic degeneration.”
“Progress in
Jones and his team have developed new criteria to help physicians diagnose LANS, which include the following core clinical factors:
These new criteria were developed and validated using data from more than 200 participants in the Mayo Clinic Alzheimer’s Disease Research Center, Mayo Clinic Study of Aging, and Alzheimer’s Disease Neuroimaging Initiative databases.
“In our clinical work, we see patients whose memory symptoms appear to mimic Alzheimer’s disease, but when you look at their brain imaging or biomarkers, it’s clear they don’t have Alzheimer’s disease,” Jones said in a press release.
“Until now, there has been no clear medical diagnosis to base this on, but now we can offer them answers. This research creates a clear framework that other healthcare professionals can use to care for their patients. It has major implications for treatment decisions, including amyloid-lowering drugs and new clinical trials, as well as for counseling on prognosis, genetics and other factors.”
— David T. Jones, MD, lead author
The researchers also looked at a specific protein called
“The TDP-43 protein is critical in defining LATE-NC,” Jones said. “It’s something that pathologists see at autopsy and indicates that some type of degenerative limbic disease has affected a patient during their lifetime.”
“LANS can be diagnosed at the stage of mild cognitive impairment or dementia. Mild cognitive impairment and dementia are umbrella terms for cognitive symptoms with a variety of underlying causes. LANS can also have a variety of underlying causes, but they are more limited to isolated degenerative conditions of the limbic system, with LATE-NC being the most common, but rare forms of Alzheimer’s disease or other tauopathies can also cause LANS,” he continued.
Jones said these new criteria can now be used in clinical practice to inform the diagnosis of LANS, which can then guide medical advice and management recommendations.
“As research on LANS syndrome progresses, recommendations for medical counseling and management will improve,” he said. “I use (this criterion) in my practice now. All clinical trials in Alzheimer’s disease would be improved if they included the probabilities of LANS and assessed responses to various treatments based on these criteria. We also need clinical trials tailored to subjects diagnosed with LANS syndrome. We also need studies of the clinical utility of the diagnosis of LANS syndrome that would include longitudinal observational cohorts with a variety of measures common to age and dementia research.”
“Understanding age-related changes in memory is critical to detecting and intervening early on underlying causes, improving quality of life, and developing tailored therapies,” Jones added. “It also provides insights for patients and families, supports better care and mental health outcomes, and informs public health policy for aging populations.”
MNT I also spoke with David Merrill, MD, PhD, a geriatric psychiatrist and director of the Pacific Brain Health Center at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California, about this research.
Merrill said this is good news for older people with isolated memory loss.
“They may have this newly identified disorder, LANS, which is likely to remain a mild clinical syndrome over time,” he explained.
“Alzheimer’s disease and other memory syndromes have a more rapid, severe, and disabling progression than that described in LANS syndrome. Being diagnosed with LANS may mean that the feared worst-case scenario will not occur. In effect, these patients with LANS do not actually have Alzheimer’s disease.”
— David Merrill, MD, Ph.D.
“Creating an interinstitutional registry of these cases so that we can identify the underlying causes associated with the development of LANS will help identify treatments that need to be administered and/or developed to help these patients,” Merrill added.