As one ages, memory does decline. There are various reasons for this, and different variations of memory loss. The factors vary from subject to subject, but in the end it leads to the same basic fact. When individuals age, there are many declines in ageing, despite physical health. Still about a third to a half of healthy people develop some form of memory loss or impairment.
Major theories held by neurologists believe that gradual deterioration of the brain is the cause.
Forgetfulness in the aged could be caused by hippocampal disfunction by this theory. Another theory deals with the frontal lobes. They have the greatest loss of neurons and decrease in volume. There are many theories about how memory is lost over time. Most of the latest deal with the physical breakdown of the human brain.