The most common form of dementia is Alzheimer's disease (AD), and retro-genesis has been a common disorder of the elderly. In studies they have compared Alzheimer's with different stages of adolescent behavior. The term Retrogenesis suggests that the brain of a person with Alzheimer's disease deteriorates in the reverse order. During this process individuals lose their cognitive abilities and begin to revert back to childlike behavior, and continue to deteriorate over the course of the next several years. The middle stage is when most of the difficult behaviors begin. The average cognitive and functional levels are that of a four year old and will continue to deteriorate. This is when the need for 24-hour care may become necessary. During the last stage the person can deteriorate to the functional level of a newborn. The comparison to developmental stages in children is useful in understanding the disease process. .
Alzheimer's disease begins in the entorhinal cortex area near the hippocampus. The hippocampus is essential for short and long term memories. The changes in the brain can start 10-20 years before any symptoms occur. Alzheimer's is not a normal part of aging. This is a slow disease starting with minimal memory problems and ending with severe brain damage. Individuals with dementia of Alzheimer's and vascular dementia have shown the signs and symptoms of retrogenesis. An individual can live up to 20 years after being diagnosed. There are several stages to the Retrogenesis beginning at stage 1 – stage 7. During these stage people lose their abilities to function by themselves, and may need extensive assistance. During Stage 1 people function as normal individuals experience no memory problems or cognitive declines. They would be considered normal. They could hold down jobs and live normal lives. This stage could last several years.
In Stage 2 individuals show a very mild cognitive decline similar to normal age-related changes.