Neurodegenerative diseases

Neurodegenerative diseases are a heterogeneous group of disorders that are characterized by the progressive degeneration of the structure and function of the nervous system. They are incurable and debilitating conditions that cause problems with mental functioning also called dementias. Neurodegenerative diseases affect millions of people worldwide. Alzheimer’s disease and Parkinson’s disease are the most common neurodegenerative diseases. In 2016, an estimated 5.4 million Americans were living with Alzheimer’s disease. An estimated 930,000 people in the United States could be living with Parkinson’s disease by 2020.

Alzheimer's disease is a progressive neurologic disorder that causes the brain to shrink (atrophy) and brain cells to die. Alzheimer's disease is the most common cause of dementia — a continuous decline in thinking, behavioral and social skills that affects a person's ability to function independently.

Approximately 5.8 million people in the United States age 65 and older live with Alzheimer's disease. Of those, 80% are 75 years old and older. Out of the approximately 50 million people worldwide with dementia, between 60% and 70% are estimated to have Alzheimer's disease.