Dementia cases are made up in proportion of 60 to 70 percent by Alzheimer’s disease, a chronic neurodegenerative condition that leaves the patient with an average life expectancy of three to nine years, depending on how early the diagnosis is made.
But according to a new study published in the journal Alzheimer’s and Dementia, researchers have discovered certain bio-makers that can point to early onset of Alzheimer’s years before actual symptoms appear; it turns out that the disease is at work in the mind long before that.
Indiana University researchers have found that the genetic trait associated with Alzheimer’s disease might be enabling the multiplication of plaque accumulations in the brain before any other symptoms can be detected through tests.
Scientists focused on participants in the study that dealt with “subjective cognitive decline.” This group included people in their older age who had trouble recalling memories from months or years back; what was interesting, however, is that their performance in memory and standard cognition tests fell in the normal ranges.
Shannon L. Risacher, Ph.D., and Andrew J. Saykin, Psy.D were the leading researchers in this study, and they had a great task in front of them: collecting and analyzing data of approximately 600 patients suffering from Alzheimer’s Disease Neuroimaging Initiative (ADNI), and then focusing on those carrying the mutation in the APOE e4 gene.
After cross-referencing this group with the patients in the “significant memory group,” researchers discovered that various bio-markers pointed to pathologies similar to Alzheimer’s. For example, they noticed raised levels of amyloid plaque, the protein that often accumulates in the brain tissue and is associated with Alzheimer’s.
Scientists also observed that the amyloid protein levels in the cerebrospinal fluid were low before the plaques started forming, supporting the theory that the protein is vital in the brain’s plaque formation process.
At the same time, the tau levels – another protein present in the cerebrospinal fluid in Alzheimer’s patients – were also increased prior to the plaque accumulation. Because the study focused on early onset of the neurodegenerative disease, researchers did not obtain any evidence pointing to atrophy of brain structures or other metabolic factors linked to late stages of Alzheimer’s development.
Dr. Risacher strongly believes these preliminary conclusions call for further research, as patients who are at a high risk of Alzheimer’s disease would greatly benefit of a breakthrough in the field.
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