Research Links Mild Cognitive Impairment to Alzheimer’s Disease

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Over 5 million people age 65 and older are living with Alzheimer’s disease — the sixth leading cause of death in the U.S. AD is a neurological condition that is marked by progressive worsening of memory loss and increasing loss of one’s ability to carry out activities of daily living.

The hallmark signs of Alzheimer’s disease are plaques and tangles. Beta-amyloid plaques are deposits of sticky proteins in the brain that clump together and interrupt the communication between neurons (nerve cells). Neurofibrillary tangles are modifications in tau, a brain protein.

These proteins damage microtubules that are responsible for the transportation of material along neuronal extensions called neurites that allow nerve cells to communicate with each other. The more plaques and tangles build up, the more pronounced an individual’s memory and cognitive deficits become.

But not every instance of forgetfulness is indicative of early AD. The brain ages just like every other organ. So as we get older, we may experience problems like remembering where we’ve placed our keys or recalling what a person’s name is. Forgetfulness is a part of getting older and is attributed to the fact that as we age brain size become smaller, inflammation and free radicals damage is increased, blood flow is reduced, and plaques and tangles are formed.

So what’s the difference between changes in the brain of a normal, aging person and someone with AD? Changes like plaques, tangles, and inflammation become worse over time and irreversibly destroy memory and cognition.

Distinguishing between signs of forgetfulness that are normal or are associated with AD have been assessed through tests like the Mini-Mental Status Exam that helps to track memory and cognitive changes in older adults. But researchers have also been exploring new ways to identify AD. Studies show that a type of mild cognitive impairment (MCI) may be a harbinger of AD.

There are many subtypes of MCI. One that has been studied and linked to the development of Alzheimer’s disease is called amnestic mild cognitive impairment (aMCI). Memory loss is the most prominent feature of aMCI. People with aMCI have been shown to progress to AD more than those without aMCI.

In one study, researchers evaluated the brain tissue of people who were diagnosed with aMCI and found that more than 70 percent of those individuals progressed to Alzheimer’s disease.

Data from a different study used MRI to identify atrophy in the hippocampus and entorhinal cortex (temporal lobe structures responsible for making and storing memories) of people with aMCI and healthy brains over a five-year period. Among those with smaller temporal lobe structures, the progression to AD was shorter.

These studies provide useful insights that may help to shape and improve the way in which AD is detected and treated. While there are drugs that are prescribed to treat AD, there is still no cure.

In my new book, The Gene Therapy Plan, I provide information on ways to promote healthy aging, namely through a wholesome diet. To avoid premature aging and to bolster brain health, skip the processed foods and consume plenty of whole foods. By eating whole foods like fruits and vegetables, herbs and spices, the body is able to obtain optimal nutrition to bolster healthy metabolism and produce lots of energy.

Photo credit: CDC/Dawn Arlotta/Cade Martin

References:

Jicha, Gregory A., Joseph E. Parisi, Dennis W. Dickson, Kris Johnson, Ruth Cha, Robert J. Ivnik, Eric G. Tangalos et al. “Neuropathologic outcome of mild cognitive impairment following progression to clinical dementia.” Archives of Neurology 63, no. 5 (2006): 674-681.

Devanand, D. P., G. Pradhaban, X. Liu, A. Khandji, S. De Santi, S. Segal, H. Rusinek et al. “Hippocampal and entorhinal atrophy in mild cognitive impairment Prediction of Alzheimer disease.” Neurology 68, no. 11 (2007): 828-836.

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