Alzheimer disease is a chronic, incurable brain disorder characterized by progressive loss of brain tissue and function. The early stages of Alzheimer disease primarily affect intellectual functions. Late-stage Alzheimer disease directly or indirectly affects other body systems. The condition is ultimately fatal. The Alzheimer’s Association estimates that up to 5.3 million men and women in the United States are living with Alzheimer disease.
Central Nervous System
Alzheimer disease is principally a disease of the central nervous system, which includes the brain and spinal cord. Although the cause of Alzheimer disease remains poorly understood, specific brain abnormalities have been identified in patients with the disorder. Amyloid plaques, composed of specific proteins and pieces of dead brain cells, progressively accumulate in the brain tissue. A naturally occurring brain protein known as tau also accumulates abnormally, causing brain cells to malfunction and eventually die.
The loss of functioning brain tissue that occurs with Alzheimer disease initially causes problems with memory and learning. As the disease progresses, intellectual function, personality and mood are increasingly affected. With late-stage disease, patients lose their sense of self and present circumstances. Patients with advanced Alzheimer disease are completely dependent on others for daily care, as they have forgotten how to go about the most basic tasks of daily living. Patients do not recognize loved ones and lose the capacity to contemplate, plan, rationalize, organize and interact with their environment,