What is Alzheimer’s Disease?

What is Alzheimer’s disease? A progressive form of dementia, is the most common form of neurodegenerative disease. The disease accounts for approximately 40-80% of all dementia cases. Though not all forms of the disease are familiar, it can be inherited, and there are ongoing studies on the genes that appear important in the development of Alzheimer’s disease.

Physiologically, Alzheimer’s disease involves death and damage to brain cells that are irreversible. Much of the destruction that occurs in Alzheimer’s disease occurs in parts of the brain that are critical for memory, such as the cortex and the hippocampus. The disease is also characterized by more specific changes in the brain, including the accumulation of what are known as plaques and tangles, made up of beta-amyloid protein and tau protein, respectively. By the time symptoms of Alzheimer’s disease occur, these physiological changes in the brain have already begun.

The only way to definitively diagnose Alzheimer’s disease is to assess the brain after a patient has died. However, there are a number of ways healthcare providers evaluate patients in clinical settings to determine if they are likely suffering from this form of dementia. In addition to the symptoms of Alzheimer’s disease, which include memory and decision making deficits, disorientation, confusion, and changes in personality and mood, clinicians assess neurological functioning and images of the brain, which can help rule out other conditions that may have overlapping symptoms with Alzheimer’s disease. More comprehensive tests of mental status are usually undertaken as a way to provide a diagnosis of the disease.

There are no treatments that cure Alzheimer’s disease, but there are drugs that improve the symptoms associated with the disease. These medications help some, but not all patients, and are sometimes associated with unwanted side effects. There is a significant amount of research focused on finding a cure for Alzheimer’s disease.

Because the build-up of plaques and tangles are thought to contribute to the debilitating symptoms of Alzheimer’s disease, drug developers have aimed to develop medicines that prevent the development of plaques and tangles or to disrupt plaques and tangles once they have formed. However, none of these efforts have yet led to a fully successful treatment for Alzheimer’s disease.

References

Dubois, B., Feldman, H. H., Jacova, C., Cummings, J. L., Dekosky, S. T., Barberger-Gateau, P., . . . Scheltens, P. (2010). Revising the definition of Alzheimer’s disease: a new lexicon. Lancet Neurol, 9(11), 1118-1127. doi: 10.1016/s1474-4422(10)70223-4

Mattson, M. P. (2004). Pathways towards and away from Alzheimer’s disease. Nature, 430(7000), 631-639. doi: 10.1038/nature02621

Nussbaum, R. L., & Ellis, C. E. (2003). Alzheimer’s disease and Parkinson’s disease. N Engl J Med, 348(14), 1356-1364. doi: 10.1056/NEJM2003ra020003