When is Alzheimer’s disease not Alzheimer’s disease? As it turns out, that’s not an easy question to answer, even for medical experts. There are several other conditions easily mistaken for Alzheimer’s, including a newly labelled one – Limbic-predominant Amnestic Neurodegenerative Syndrome (LANS).
The reason for the potential misdiagnosis is that several diseases, including LANS, share symptoms very similar to Alzheimer’s. In addition, the fact that Alzheimer’s is the most common form of dementia may lead to an inherent unconscious bias towards such a diagnosis.
In the case of LANS, the good news is that researchers have developed new criteria to help doctors diagnose the condition. And an earlier correct diagnosis opens the door for more timely and appropriate treatment.
What is LANS?
As suggested by the ‘L’ in LANS, it is a progressive degenerative condition of the body’s limbic system. The limbic system is part of the brain and plays a very important part in our memory.
“When this system degenerates, it becomes difficult for people to form new memories,” said David T. Jones, MD. Dr Jones is a neurologist at the Mayo Clinic and senior author of the newly published research. According to Dr Jones, LANS often leads “to difficulty recalling recent events, repeating statements that have already been said, and problems recalling names”.
While LANS is a separate condition to Alzheimer’s, it has a number of underlying causes of its own.
Although this throws up the possibility of complicating matters further, new advances in medical technology have improved the chances of accurate diagnoses.
The research breakthrough surrounds what are known as biomarkers. A biomarker (short for biological marker) is defined by the US government’s National Institute of Environmental Health Sciences as “an objective measure that captures what is happening in a cell or an organism at a given moment”.
Biomarkers can serve as early warning systems for your health. They measure levels of various chemicals – for example lead or cholesterol – in the bloodstream or other parts of the body.
Researchers have developed a series of biomarkers that indicate Alzheimer’s disease. Through these they have developed a process of more clearly differentiating LANS from the majority symptoms caused by Alzheimer’s disease.
Spotting the difference
Dr Jones’s team identified a number of core clinical factors that point to a LANS diagnosis. These include:
- presents with a slow, predominant neurodegenerative condition with memory loss that has gradually progressed for two or more years that cannot be linked to another disease
- age of 75 years or older
- mild clinical syndrome
- disproportionate hippocampal atrophy
- impaired semantic memory
- limbic hypometabolism and absence of neocortical degeneration
- low likelihood of neocortical tau pathology.
Although several of these terms may seem foreign to you, there’s no need to worry. The important thing is that the doctors charged with diagnosing LANS (or another condition) understand them.
How will a LANS diagnosis change things?
A diagnosis of LANS rather than Alzheimer’s can have a significant impact. The general medical consensus is that LANS is expected to remain a mild clinical syndrome over time. This provides both relief for the diagnosed patient, and a different approach to treatment.
Dr Jones says he already uses the criteria in his own practice. He believes “all clinical trials for Alzheimer’s disease would be improved if they include LANS likelihoods”.
Further clinical trials could help bed down and refine diagnosis techniques, he said.
Such trials would mark another small step in our understanding of the brain, and how to keep it healthy for longer.
Do you have trouble with your memory? Have you sought medical advice on the matter? Let us know via the comments section below.
Also read: Lewy body dementia and its prognosis
