How long can amnesia last?
1042651#10
Studies on specific cases demonstrate how particular impaired areas of the hippocampus are associated with the severity of RA. Damage can be limited to the CA1 field of the hippocampus, causing very limited RA for about 1 to 2 years. More extensive damage limited to the hippocampus causes temporally graded amnesia for 15 to 25 years. Another study also suggests that large medial temporal lobe lesions, that extend laterally to include other regions, produce more extensive RA, covering 40 to 50 years. These findings suggest that density of RA becomes more severe and long-term as the damage extends beyond the hippocampus to surrounding structures.
Retrograde amnesia
15767764#51
Researchers have investigated the relationship between posttraumatic amnesia (PTA) resulting from traumatic brain injury (TBI) and the development of symptoms of posttraumatic stress disorder (PTSD) and acute stress disorder (ASD). 282 outpatients, who were an average of 53 days post-TBI in their recovery, were divided into four groups: PTA episode lasting less than one hour; PTA episode lasting between one hour and 24 hours; PTA episode lasting between 24 hours and one week; and PTA episode lasting for longer than one week. The patients' personal details were used as variables classified for age, gender, marital status, time elapsed between injury and assessment, and type of injury (motor vehicle accident, pedestrian, assault and other). Patients were given two self-report inventories: the Impact of Event Scale (IES) and the General Health Questionnaire (GHQ). The IES measures symptoms of PTSD and contains questions regarding the intrusiveness of the traumatic event (ex. nightmares) and avoidant behaviours related to the traumatic event (ex. avoiding a certain location). The GHQ was used as an indicator of overall psychological health. The majority of subjects were in Group 1 (PTA episode lasting less than one hour), injured in motor vehicle accidents, and male.
Post-traumatic amnesia
21347303#0
Amnesia is a deficit in memory caused by brain damage, disease, or psychological trauma. Amnesia can also be caused temporarily by the use of various sedatives and hypnotic drugs. The memory can be either wholly or partially lost due to the extent of damage that was caused. There are two main types of amnesia: retrograde amnesia and anterograde amnesia. Retrograde amnesia is the inability to retrieve information that was acquired before a particular date, usually the date of an accident or operation. In some cases the memory loss can extend back decades, while in others the person may lose only a few months of memory. Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store. People with this type of amnesia cannot remember things for long periods of time. These two types are not mutually exclusive; both can occur simultaneously.
Amnesia
15973599#9
Priming studies on Cochrane revealed that individuals with severe amnesia can display intact priming capabilities regardless of episodic memory damage. Priming involves initially exposing a subject to a word or image so that a memory of that word or image can be formed. This is meant to improve a subject's recall of that word or image when that word or image is shown at a later time. Cochrane additionally showed that priming effects can last for long periods of time; in one study, researchers presented Cochrane with a list of words, and after 12 months showed him the same words with letters missing. Cochrane was able to complete these fragmented words as successfully as a person with normal brain function who was shown the same list initially. This challenged the previous opinion that patients with anterograde amnesia are incapable of adding information to their declarative memory.
Kent Cochrane
9501260#11
For practical purposes, organizational memory (OM) can be broken down into three distinct time frames. Short-term OM lasts up to about five years; medium-term OM occupies a time frame of up to around ten years, with periods in excess of this constituting long-term OM. Typically existing only in the minds of individuals, it is normally very difficult to share and to capture. Because of its contemporary and contiguous nature, short- and medium-term OM is generally more relevant to operational issues facing the organization, whilst long-term OM is more conformant with strategy and culture.
Corporate amnesia
3320309#16
There have been assertions of a possible link between TGA and the use of statins (a class of drug used in treating cholesterol).
En bloc memory loss which is total, permanent, and irrecoverable can occur as an alcoholic "black out," usually lasting longer than an hour and up to 2–5 days.
Marijuana intoxication, Halogenated hydroxyquinolines such as Clioquinol, PDE inhibitors such as sildenafil, Digitalis and scopolamine intoxication, and general anaesthesia have been reported with TGA.
A differential diagnosis should include:
If the event lasts less than one hour, transient epileptic amnesia (TEA) might be implicated.
Transient global amnesia
15767764#0
Post-traumatic amnesia (PTA) is a state of confusion that occurs immediately following a traumatic brain injury (TBI) in which the injured person is disoriented and unable to remember events that occur after the injury. The person may be unable to state their name, where they are, and what time it is. When continuous memory returns, PTA is considered to have resolved. While PTA lasts, new events cannot be stored in the memory. About a third of patients with mild head injury are reported to have "islands of memory", in which the patient can recall only some events. During PTA, the patient's consciousness is "clouded". Because PTA involves confusion in addition to the memory loss typical of amnesia, the term ""post-traumatic confusional state"" has been proposed as an alternative.
Post-traumatic amnesia
21347303#14
Studies were completed consistently throughout Molaison's lifetime to discover more about amnesia. Researchers did a 14-year follow-up study on Molaison. They studied him for a period of two weeks to learn more about his amnesia. After 14 years, Molaison still could not recall things that had happened since his surgery. However, he could still remember things that had happened prior to the operation. Researchers also found that, when asked, Molaison could answer questions about national or international events, but he could not remember his own personal memories. After his death Molaison donated his brain to science, where they were able to discover the areas of the brain that had the lesions which caused his amnesia. This case study provided important insight to the areas of the brain that are affected in anterograde amnesia, as well as how amnesia works.
Amnesia
33034803#22
Even when childhood events are not remembered episodically, they can be implicitly remembered. Humans can be primed and implicitly trained earlier before they can remember facts or autobiographical events. This is most important in terms of emotional trauma. Adults can generally recall events from 3–4 years old, and have primarily experiential memories beginning around 4.7 years old. However, some suggest that adults who had traumatic and abusive early childhoods report an offset of childhood amnesia around 5–7 years old. It has been suggested that this is because stressful experiences can injure memory centers and possibly make it harder to form memories. This coupled with the fact that priming can occur at a younger age may indicate that children in abusive situations have implicit memory connections that were formed in response to the abuse. Whether or not these 'repressed' memories can affect individuals is a matter of considerable debate in psychology.
Childhood amnesia
530537#0
Anterograde amnesia is a loss of the ability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact. This is in contrast to retrograde amnesia, where memories created prior to the event are lost while new memories can still be created. Both can occur together in the same patient. To a large degree, anterograde amnesia remains a mysterious ailment because the precise mechanism of storing memories is not yet well understood, although it is known that the regions involved are certain sites in the temporal cortex, especially in the hippocampus and nearby subcortical regions.
Anterograde amnesia
15767764#25
Duration of PTA may be difficult to gauge accurately; it may be overestimated (for example, if the patient is asleep or under the influence of drugs or alcohol for part of the time) or underestimated (for example, if some memories come back before continuous memory is regained). The Galveston Orientation and Amnesia Test (GOAT) exists to determine how oriented a patient is and how much material they are able to recall.
The GOAT is the most widely used standardized scale for the prospective assessment of PTA in the United States and Canada. The test is made up of 10 items that assess orientation and recollection of the events before and after the injury. It can be used to assess the duration of PTA; this particular GOAT assessment has been found to strongly predict functional outcome as measured by the Glasgow Outcome Scale, return to productivity, psychosocial function and distress.
Post-traumatic amnesia