2. Boundary Effect
This forgetfulness might manifest itself in a very specific manner, known as the boundary effect.
In the boundary effect, an individual is prone to forgetting things as soon as they pass through a door (the boundary in question). For example, they might enter a room to retrieve an item and then forget why they came in.
The boundary effect is actually a psychological phenomenon that is noticed in healthy patients too. The difficulty is recognizing the point at which it has developed beyond its normal limits and become a serious problem.