Amnesia refers to the loss of memory from disease or trauma. The extent and type of memory loss is dependent on the area of the brain that is damaged. Individuals with retrograde amnesia suffer from memory losses of past events. This is a common occurrence when head injury is involved. Oftentimes, an individual will not be able to recall the events and moments immediately preceding an accident or fall.

Individuals who suffer from anterograde amnesia are unable to store additional memories, but their earlier memories are intact and accessible. They have difficulty creating new long-term memories. As a consequence, every experience is a new experience for these individuals, even if they have experienced it earlier, such as meeting a new person or reading a new book.