Amnestic Disorder
Ø Group of disorder that involve loss of memories previously established, loss of the ability to create new memories, or loss of ability to learn new information.
Ø Can be temporary or permanent memory loss.
Ø Discrete memory impairment without any symptoms of other cognitive disorders.
Types of Amnestic Disorder
Ø Retrograde Amnesia
Ø Anterograde Amnesia
Ø Transient Global Amnesia
Retrograde Amnesia
Ø Loss of memory-access to events that occurred, or information that was learned, before an injury or the onset of disease.
Causes: dementia , head injuries , head trauma.
Symptoms: false memories, confusion, brain/coordination problems, forgetting past events as opposed to new one.
Anterograde Amnesia
Ø Unable to store and retain new information but is able to recall data and events that happened previously.
Ø Effect be can temporary or permanent.
Ø It can be temporary when the person took too much alcohol or alcoholism. And it can be permanent if person experience that the area of the brain known as hippocampus is damaged. Hippocampus- is responsible in forming memories.
Causes: accident, result of surgery, alcohol, trauma and even an acute deficiency of thiamine known as Korsakoff's syndrome.
Korsakoff's syndrome- chronic memory disorder caused by severe deficiency of thiamine(vitamin B1). Common caused by alcohol misuse.
Symptoms: confusion, forgetting .
Transient Global Amnesia
Ø Memory loss that experience confusion or agitation. Person is not able to make new memories. The person may be disoriented in regard to time and place, but can remember who they are and can recognize family members. TGA typically lasts for several hours but can last up to ten hours.
Ø Person will never remember what happened during this period, but all other memory is usually intact.
Causes of TGA is unclear.
Causes of Amnestric Disorder
· Stroke or cerebovascular disease
Condition that affect the flow of blood through the brain that affects the motor skills of a person, such as ability to walk, as well as fluency in any language you speak.
· Alcohol Use
Short-term alcohol use can cause blackout. This is temporary form of anterograde amnesia. Long-term alcoholism can cause wernicke-Korsakoff' syndrome. If you develop this condition, you will have difficulty forming new memories but may not be aware of it.
· Trauma/stress
Severe trauma or stress can also cause dissociative amnesia. With this condition, your mind rejects thoughts, feelings, or information that person are too overwhelmed to handle. A specific type of dissociative amnesia called dissociative fugue, can lead to unexpected travelling ir wandering. It can also lead to amnesia around the circumstances of traveling as well as forgetting other details of your life.
· Head Injuries
Traumatic head injuries, as well as stroke, tumors, and infections, can also cause damage to your brain. This damage can include permanent memory problems. Conclusions commonly disrupt memories of the hours,days, or weeks before and after you were injured.
· Anoxia
A depletion of oxygen levels can also affect your entire brain and lead to memory loss. This condition is called anoxia. If the anoxia is not severe enough to cause brain damage. The memory loss can be temporary.
· Dementia
A memory's location in you brain is thought to depend on it's age. To lose old memories. You must have widespread brain deterioration. This can be caused by Akzheimer's disease or ther forms of dementia. People with dementia usually lose more recent memories first and keep older memories longer.
Diagnosis
Amnestic disorders may be self-reported, if the patient has retained insight into his or her memory problems. More often, however, the disorder is diagnosed because a friend, relative, employer, or acquaintance of the patient has become concerned about the memory loss or recognizes that the patient is confabulating, and takes the patient to a doctor for evaluation. Patients who are oriented, or whose amnesia is associated with head trauma or substance abuse, may be taken to a hospital emergency room.
The doctor will first examine the patient for signs or symptoms of traumatic injury, substance abuse, or a general medical condition. He or she may order imaging studies to identify specific areas of brain injury, or laboratory tests of blood and urine samples to determine exposure to environmental toxins or recent consumption of alcohol or drugs of abuse. If general medical conditions and substance abuse are ruled out, the doctor may administer a brief test of the patient's cognitive status, such as the mini-mental state examination or MMSE. The MMSE is often used to evaluate a patient for dementia, which is characterized by several disturbances in cognitive functioning(speech problems, problems in recognizing a person's face etc.) that are not present in amnestic disorders. The doctor may also test the patient's ability to repeat a string of numbers(the so called digit span test) in order to rule out delirium. Patients with an amnestic disorder can usually pay attention well enough to repeat a sequence of number where as patients with delirium have difficulty focusing or shifting their attention. In some cases the patient may also be examined by a neurologist (a doctor who specializes in disorders of the central nervous system).
If there is no evidence of a medical condition or substance use that would explain the patient's memory problems, the doctor may test the patient's memory several times in order to rule out malingering or a factitous disorder. Patients who are faking the symptoms of an amnestic disorder will usually give inconsistent answer to memory tests if they are tested more than once.
Treatment
There are no treatments that have been proved effective in most cases of amnestic disorder, as of 2002. Many patients recover slowly over time, and sometimes recover memories that were formed before the onset of the amnestic disorder. Patients generally recover from transient global amnesia without treatment. In people judged to have the signs that often lead to alcohol-induces persisting amnestic disorder, treatment with thiamin may stop the disorder from developing.
Prognosis
Amnestic disorders caused by alcoholism do not generally improve significally over time, although in a small number of cases the patient's condition improves completely. In many cases the symptoms are severe, and in some cases warrant long-term care for the patient to make sure his or her daily needs are met. Other substance induces amnestic disorders have a variable rate of recovery, although in many cases full recovery does eventually occur. Transient global amnesia usually resolves fully.
Prevention
Amnestic disorder resulting from trauma are not generally considered preventable. Avoiding exposure to environmental toxins, refraining from abuse of alcohol or other substances, and mainting a balanced diet may help to prevent some forms of amnestic disorders.
References:
en.m.wikipedia.org
study.com
