Alzheimers: New Symptoms May Mean That Neurodegeneration Began In The Past

First Posted: Jul 15, 2015 10:23 AM EDT

The first signs of Alzheimer's may not actually be the intial symptoms of the illness taking root. Quite the contrary, actually.

A recent study published in the journal Alzheimer's and Dementia reveals that changes in prevalent bio markers linked to the neurodegenerative health issue may begin between the ages of 20-30. However, symptom manifestations of the disease will probably not begin to surface until much later in life, at around 65 and up. 

Of course, a memory slip here or there is not necessarily a cause for concern. However, it's also important to remember that while some symptoms will not occur in the beginning, any potential issues should be promptly addressed. Previous studies show that many affected, exhibiting definite symptoms of Alzheimer's or another form of dementia, will oftentimes go undiagnosed for years. 

Lead study author by Shannon L. Risacher, Ph.D., assistant professor of radiology and imaging sciences, and Andrew J. Saykin, Psy.D., director of the Indiana Alzheimer Disease Center and IU Center for Neuroimaging collected data as part of the national Alzheimer's Disease Neuroimaging Initiative (ADNI), a global public-private project that's working to collect and make available a wide range of long term Alzheimer's related data from volunteers ranging to cognitively normal "controls" to those suffering from the health issue.

During the study, researchers examined a potential gene in question known as APOE, which carries several variants or "alleles." One of the variants, APOE e4, have been linked to an increased risk of Alzheimer's development in older adults. Furthermore, APOEe4 is relatively common, and has been found in about 25 percent of the population. Patients with this gene also tend to have an ealier onset of symptoms.

Researchers looked at data from nearly 600 ADNI participants, comparing those with APOE e4 varients to those with other genes. Researchers found that those with the APOEe4 gene showed signs of Alzheimer's like pathologies via several biomarkers. This included things like increased amyloid plaque levels, clumps of protein fragments in the brain tissue, decreased levels of protein precurors to plaques in the cerebrospinal fluid and increased levels of tau in the cerebrospinal fluid, according to News Medical.

However, researchers could not quite discover evidence of reduced levels of glucose metabolism or atrophy of brain structures associated at later stages of Alzheimer's progression.

"ADNI provides access to a wide range of biomarkers, structural and functional neuroimaging with MRI, PET scans for amyloid and for glucose metabolism, CSF biomarkers for amyloid and tau, plus genetics, and clinical and cognitive tests. No other data set has all these state-of-the-art biomarkers available for analysis," Dr. Saykin concluded.

More information regarding the findings can be seen via the  the journal Alzheimer's and Dementia.

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