Alzheimer's Variant Often Goes Unnoticed

An unusual variant of Alzheimer's disease if often misdiagnosed and may be going unnoticed in an estimated 600,000 Americans, according to the results of a recent research conducted by the Mayo Clinic.

The findings were recently presented at the American Academy of Neurology's Annual Meeting in Philadelphia, Pennsylvania.

According to a Mayo Clinic press release, the researchers analyzed the brains of 1,821 patients at the Mayo Clinic in Jacksonville, Florida who had been confirmed with Alzheimer's disease.

In an attempt to differentiate the different type of Alzheimer's subtypes, the researchers kept a record of the number of tau-caused tangles in the brain and the levels of brain-plaque-causing amyloid beta -- two hallmark causes of Alzheimer's disease.

Interestingly, the researcher quickly determined that while amyloid beta levels remained constant among all types of Alzheimer's, variants of the disease showed displayed unequal tangling between different parts of the brain.

A variant the researchers called "hippocampal sparring" Alzheimer's  was quickly identified by significantly more tau-caused tangles in the hippocampus, compared to other parts of the brain. According to the release, the researcher theorize that in these cases, the tau protein in the brain works in such a way to specifically "spar" with neurons in the hippocampus, damaging parts of the brain associated with behavior, motor recognition, and use of speech and vision. In contrast, standard Alzheimer's disease would have simply inflicted wide-spread damage that inhibits overall function and negatively influences memory and learning processes.

According to the researchers, 11 percent of this patients were identified with the hippocampus sparring Alzheimer's variant. The patients did not exhibit standard Alzheimer's symptoms. Instead they appeared to have developed angry behavioral problems, unfamiliarity with their own limbs, and visual interruption and language problems. In additional, as the damage is more focused compared to standard Alzheimer's disease, it appears that the condition of patients with this variant deteriorates more quickly.

Naturally, as this condition does not present itself like standard Alzheimer's it is very likely that it will be misdiagnosed, the researcher report. Working off their sample model, the researchers determined that approximately 600,000 people might be suffering from this condition in the U.S. alone, with a great portion of them not even receiving adequate treatment.

These results were presented at the American Academy of Neurology's Annual Meeting in Philadelphia, Pennsylvania and should be viewed as preliminary findings until they are published in a peer-reviewed journal.

A Mayo Clinic press release detailing the findings was published on April 30.