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Medical Author:

Norberto Alvarez, MD

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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The neurodegenerative disorders in the brain that result in Alzheimer's disease start years, probably decades, before the beginning of clinical symptoms. This long period of time between the beginning of the pathological changes and the early symptoms opens a window of opportunity for early diagnosis and treatment. Unfortunately, at the present time no treatment is available to stop the progression of the disease.

There are two main changes in brain tissue that are associated with Alzheimer's disease.

1. The abundant presence of the so-called "senile plaques." These plaques are the result of the extracellular deposit of a protein fragment that is naturally produced inside the brain, known as amyloid A-beta 1-42. This protein accumulates in the parenchyma of the brain, that is, the area outside the nerve cells. The reason for this excessive accumulation is not clear but it is considered one of the landmarks of Alzheimer's disease.
2. The presence (different from the plaques) of abnormal deposit of substances inside the cells of the brain. These intracellular deposits are called "neurofibrillary tangles" and "neuropil threads." The latter are composed of a protein called "Tau protein."

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