American Psychological Association (APA): Alzheimer’s diseaseAlzheimer’s disease is a chronic brain disease that gradually erodes an individual’s memory, intellectual abilities, and personality. During the early stages, the most obvious symptom is an inability to learn and remember new information. In advanced stages, the ability to think, speak, or perform such basic tasks as getting dressed or eating is severely impaired. The time between diagnosis and death typically ranges from seven to 10 years.