Dementia is the loss of cognitive functioning, such as thinking, remembering, and reasoning. The loss of cognitive function and behavioral abilities can become so severe that it interferes with a person’s daily life and activities. Alzheimer’s disease is the most commonly diagnosed form of dementia in older adults.

Alzheimer’s disease is named after Dr. Alois Alzheimer. In 1906, Dr. Alzheimer examined the brain tissue of Auguste Deter, a woman who had died of an unknown mental illness in a Frankfurt, Germany asylum. Deter’s symptoms included memory loss, language problems, and unpredictable behavior. During the examination after her death, he found many abnormal clumps (amyloid plaques) and tangled bundles of fibers (neurofibrillary, or tau, tangles). These plaques and tangles are still considered some of the main features of Alzheimer’s.

Memory problems which start to disrupt daily life are usually one of the first signs of cognitive impairment related to Alzheimer’s. Some people with memory problems have a condition called mild cognitive impairment (MCI). People with MCI have more memory problems than normal for their age, but their symptoms do not interfere with their everyday lives. Older people with MCI are at greater risk for developing Alzheimer’s, but not all of them do so.

However, the first signs of Alzheimer’s can vary from person to person. For many, a decline in nonmemory aspects of cognition, such as word finding, vision and/or spatial issues, and impaired reasoning or judgment may be an indicator of very early stages of the disease.

While there is ongoing research, scientists still don’t fully understand what causes Alzheimer’s disease in most people. The causes are most likely a combination of age-related changes in the brain, along with genetic, environmental, and lifestyle factors.

For more in-depth information about Alzheimer’s disease, dementia, and how it’s diagnosed, here are some reliable resources:

(Sources: National Institute on Aging, Wikipedia)