Memory is the encapsulating term for the process by which we remember facts and events from the past; the past could refer to something that happened hours, days, months or even years ago. By this knowledge, memory loss or amnesia refers to the process whereby individuals lose the ability to remember and recall these events or learnt information. The amount they can recall varies from person to person; some people may not be able to recall a memorable event that happened years ago and some may not even be able to recall something that happened mere seconds or minutes beforehand. Their amnesia may have been getting progressively worse or may have occurred suddenly due to a head trauma. Many people feel as though it is caused by dementia, fearing the worst, and this can be distressing for them and their family, but this is often not the case (NHS Choices, 2013).
There are two types of amnesia and they focus on the creation and restoration of memories. The first and most common is retrograde amnesia which is where the patient is unable to access old memories; it has been found that very old memories are easier to recall in this instance than memories from the recent past. The other type is anterograde amnesia whereby the patient struggles to form new memories despite how many times the memory has occurred, for example, some people can struggle to recall a fact they have just been told multiple times (Baddeley, 2004). In most cases, these two types are not separate issues. Most patients who have
10271312 problems with new learning (anterograde amnesia) will also suffer from retrograde amnesia, although they may suffer more from one type than the other.
In 1953, a case study was carried out on a patient anonymised as H.M. had to go through a bilateral temporal lobe re-sectioning in order to reduce his epilepsy after medication proved useless in his case. As a result of this, he suffered long term memory problems including an inability to recognise doctors he had met many times; an inability to remember significant events in his life; a profound inability to learn definitions of words and sufficient impairment in tests of recall and recognition. He seemed to be suffering more from anterograde amnesia. On the other hand, his intellect and general cognitive functioning remained sound. In fact, his procedural memory seemed to improve the more he carried out tasks after his prior memory loss
(Milner, Corkin & Teuber, 1968).
These findings allowed scientists to determine that different parts of the brain acted in different types of memory storage, such as the hippocampus being a key processor of facts and events. Also, scientists could tell that H.M. had not damaged his basal ganglia in the brain because this area of the brain being impaired tends to result in inability to learn skills procedurally (Gabrieli, 1995). Individuals with amnesia can therefore still learn new skills and show memory improvement in a variety of indirect tests of memory, i.e. they show repetition priming. However, as H.M. is only one case, it is hard to generalise his findings to everyone else due to individual differences. Another case study was carried out on a subject called E.P. which also showed that learning new information is possible in most amnesiacs that have suffered damage to the medial temporal lobe, more specifically the hippocampal region. This was carried out by Bayley and Squire (2002) who tested semantic learning. At this time, E.P. was 79 years old and had significant anterograde and retrograde amnesia after brain damage. Although E.P. had much poorer performances when compared to controls, he demonstrated considerable learning of new information and definitely improved gradually across the 24 study sessions. The researchers followed this up by suggesting