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
Case studies also show that amnesia is typically associated with damage to the medial temporal lobe. In addition, specific areas of the hippocampus (the CA1 region) are involved with memory. Research has also shown that when areas of the diencephalon are damaged, amnesia can occur. Recent studies have shown a correlation between deficiency of RbAp48 protein and memory loss. Scientists were able to find that mice with damaged memory have a lower level of RbAp48 protein compared to normal, healthy mice. In people suffering with amnesia, the ability to recall immediate information is still retained,[full citation needed] and they may still be able to form new memories. However, a severe reduction in the ability to learn new material and retrieve old information can be observed. Patients can learn new procedural knowledge. In addition, priming (both perceptual and conceptual) can assist amnesiacs in the learning of fresh non-declarative knowledge. Amnesic patients also retain substantial intellectual, linguistic, and social skill despite profound impairments in the ability to recall specific information encountered in prior learning episodes. The term is from Greek, meaning ‘forgetfulness’; from ἀ- (a-), meaning ‘without’, and μνήσις (mnesis), meaning ‘memory’.
There are three generalized categories in which amnesia could be acquired by a person. The three categories are head trauma (example: head injuries), traumatic events (example: seeing something devastating to the mind), or physical deficiencies (example: atrophy of the hippocampus). The majority of amnesia and related memory issues derive from the first two categories as these are more common and the third could be considered a sub category of the first.
- Head trauma is a very broad range as it deals with any kind of injury or active action toward the brain which might cause amnesia. Retrograde and anterograde amnesia are more often seen from events like this, an exact example of a cause of the two would be electroshock therapy, which would cause both briefly for the receiving patient.
- Traumatic events are more subjective. What is traumatic is dependent on what the person finds to be traumatic. Regardless, a traumatic event is an event where something so distressing occurs that the mind chooses to forget rather than deal with the stress. A common example of amnesia that is caused by traumatic events is dissociative amnesia, which occurs when the person forgets an event that has deeply disturbed them. An example would be a person forgetting a fatal and graphic car accident involving their loved ones.
- Physical deficiencies are different from head trauma, because physical deficiencies lean more toward passive physical issues. Surgery that removes part of the brain is active and thus head trauma, while the surgery also causes the surrounding areas to atrophy, which is passive. Henry Molaison is an example of physical deficiencies, because parts of his brain began to atrophy after his surgery.
Amongst specific causes of amnesia are the following:
- Electroconvulsive therapy in which seizures are electrically induced in patients for therapeutic effect can have acute effects including both retrograde and anterograde amnesia.
- Alcohol can both cause blackouts and have deleterious effects on memory formation.
Many forms of amnesia fix themselves without being treated. However, there are a few ways to cope with memory loss if that is not the case. One of these ways is cognitive or occupational therapy. In therapy, amnesiacs will develop the memory skills they have and try to regain some they have lost by finding which techniques help retrieve memories or create new retrieval paths. This may also include strategies for organizing information to remember it more easily and for improving understanding of lengthy conversation.
Another coping mechanism is taking advantage of technological assistance, such as a personal digital device to keep track of day-to-day tasks. Reminders can be set up for appointments, when to take medications, birthdays and other important events. Many pictures can also be stored to help amnesiacs remember names of friends, family and co-workers. Notebooks, wall calendars, pill reminders and photographs of people and places are low-tech memory aids that can help as well.
While there are no medications available to treat amnesia, underlying medical conditions can be treated to improve memory. Such conditions include but are not limited to low thyroid function, liver or kidney disease, stroke, depression, bipolar disorder and blood clots in the brain. Wernicke–Korsakoff syndrome involves a lack of thiamin and replacing this vitamin by consuming thiamin-rich foods such as whole-grain cereals, legumes (beans and lentils), nuts, lean pork, and yeast. Treating alcoholism and preventing alcohol and illicit drug use can prevent further damage, but in most cases will not recover lost memory.
Although improvements occur when patients receive certain treatments, there is still no actual cure remedy for amnesia so far. To what extent the patient recovers and how long the amnesia will continue depends on the type and severity of the lesion.
Content retrieved from: https://en.wikipedia.org/wiki/Amnesia.