Anterograde Amnesia

Anterograde Amnesia Definition

Anterograde Amnesia is a rare condition characterized by a typical pattern of memory loss. It is generally caused by some traumatic brain injury or a mental shock. The disorder makes it impossible for a patient to create fresh memories after the incident that leads to the amnesia. This means they are unable to remember incidences from recent past. But, their long-term memories about anything that happened before the event are not affected in any way. This is the main distinguishing feature between this type of amnesia and another similar condition named Retrograde Amnesia. Individuals suffering from the latter condition lose all memories created before the event took place. In some rare instances, these conditions may occur together in a patient.

It is still considered to be a mysterious ailment due to the lack of information about the exact mechanism responsible for storing memories. But certain areas of the temporal cortex, particularly in the hippocampus as well as the nearby subcortical regions, are known to be involved in this type of memory loss.

Anterograde Amnesia Causes

A number of possible factors, which can result in this brain disorder, include:

• Extended use of benzodiazepine drugs like flunitrazepam, midazolam, temazepam, lorazepam, nitrazepam, nimetazepam and triazolam that has strong amnesiac effects
• Non-benzodiazapine sedatives (like Zopiclone) also known to have amnesic effects (their functioning involve the same receptors as the benzodiazepine drugs)
• Traumatic brain injury, usually involving the hippocampus or the surrounding cortices
• Severe shock, stress and emotional disorders
• Tumor formation within the brain
• Severe stroke
• Low levels of oxygen supplied to the brain
• Electroshock therapy
• Encephalitis or inflammation in brain
• Dementia
• Seizure disorders
• Extreme alcohol abuse, resulting in thiamine deficiency
• Drug abuse (hallucinogens like LSD or PCP makes it difficult to memorize and recall events)
• Alzheimer’s disease
• Subarachnoid hemorrhage (bleeding from within skull and brain)
• Brain surgery

Anterograde Amnesia Pathophysiology

Its pathophysiology generally varies depending on the degree of damage as well as the affected regions of the brain. Among all the brain areas, the MTL (medial temporal lobe), fornix and basal forebrain are the parts that are best described. Scientists are still trying to find out how humans remember events on a micro-scale. There are different theories regarding the matter as neuropsychologists are still not sure whether people forget because of faulty encoding or faulty retrieval of memories. However, there is a considerable amount of data suggesting the faulty encoding hypothesis to be a likely cause.

The involvement of time in memory consolidation is another point of disagreement among neuroscientists. Research is being conducted to find out the duration of time of the memory consolidation to understand why this type of Amnesia only affects the memories that are made after the event that triggers the condition, leaving the earlier memories intact.

Anterograde Amnesia Symptoms

The symptoms and their severity depend on the underlying cause responsible for the memory loss. The onset of the symptoms may occur suddenly, without any warning signs. In cases where the condition is triggered by a serious brain injury, the symptoms occur once the individual regains consciousness following the accident. The patient always remembers everything from before the incidents.

• Partial memory loss
• Difficulty recognizing the faces of family members and close friends
• Feeling of confusion
• Difficulty in preserving new information in the brain
• Inability to remember places that used to be familiar
• Haphazard movement along with occasional tremors
• Difficulty in learning and remembering new things

Anterograde Amnesia Diagnosis

Making the diagnosis can be difficult as there are various memory disorders with similar primary symptoms. Physicians thoroughly study the signs present in a patient to detect the condition.  Various tests can also be used for confirming the diagnosis. The diagnostic procedure involves the following:

• Asking questions to patients regarding any recent head injuries. A trauma that does not cause loss of consciousness may still lead to Amnesia.
• Making enquiries to find out whether or not a patient is suffering from any disorders, such as Alzheimer’s disease, brain tumors and encephalitis that can potentially damage the brain.
• Investigating the patient has a history of drug or alcohol abuse.
• Performing routine blood tests to check for various systemic diseases.
• Use of a lumber puncture for obtaining cerebral spinal fluid to check if the individual has any nervous system infection.
• Performing brain scan or neuroimaging tests to detect any abnormality in the structure and function of the brain.
• Performing imaging techniques like MRI and CT (computed tomography) scans to detect this type of brain abnormality.
• Using EEG (electroencephalogram), a diagnostic test that is commonly used for observing the electrical activity within the brain.
• Use of a cerebral angiography for detecting decrease in the blood flow to brain.
• Use of X-ray, another useful diagnostic test that helps to detect the disorder. Diagnosticians inject contrast dye into the carotid artery or the vertebral artery to make them visible on the x-ray image.

Anterograde Amnesia Differential Diagnosis

Making a differential diagnosis of this disorder is quite difficult as there are numerous similar conditions having the same causes and symptoms. Diagnosticians should differentiate this disorder from other similar types of Amnesias, such as:

• Transient global amnesia
• Post-traumatic amnesia
• Retrograde amnesia

Anterograde Amnesia Treatment and Management

It is not possible to cure the disorder. Proper management of the condition is very important to make it possible for the patient to live as normal a life as possible. Taking the following measures can help with the management of the Amnesia:

Using Reminders

Individuals suffering from this form of memory loss remember the use of phones and the functioning of different applications. Making a record of all the important events sin their lives can help them to remember these events. Patients can also make records to remember their tasks and important works. They can also use reminders with alarms and save the important dates. The alarm can remind them about an important day on the specific date. The reminder alerts are also very useful to remind the patients of medication they have to take.

Help from Family and Friends

A patient should consult his or her family and explain to them what kind of support is required to manage the condition. Friends and family can help the patient to remember important dates and events. Having proper support from them can decrease the necessity of making notes about everything the patient need to remember. Family members can also remind the patient to write down a certain event or task before he or she forgets about it. The patient can also hire an assistant who can keep track of all the important dates, events and tasks.

Diet and Lifestyle

Following a diet containing plenty of brain food, such as apples, almonds, cumin and sage, helps to boost the patient’s memory. Reducing the amount of alcohol intake helps to manage the condition as well. Individuals with serious cases of the Amnesia should permanently give up alcohol.

Rehabilitation Therapy

Occupational therapy is a useful treatment option for these amnesiacs. Occupational therapists connect the new events and information to the old memories in the patient’s brain, thus associating the current happenings to the latter. This helps the patients to retain the new information. Memory training is a very useful method of improving one’s memory. It can help to train the minds of patients to retain the information currently being received.

Medications

No medication is available for treating individuals with severe Anterograde. Scientists are trying to determine if it is possible to reduce the symptoms with drugs that can enhance the functioning of the brain.

Anterograde Amnesia Prognosis

The prognosis is different for each patient and depends on the management of the symptoms. In many cases, the patients do not reach complete recovery, but proper management can help them to lead a relatively normal life. However, individuals with alcohol-induced Anterograde can gradually recover much of their ability to retain new information.

Anterograde Amnesia Prevention

Preventing brain injuries can reduce the risk of developing the condition. Taking the following precautions can help with the prevention:

• Wearing a helmet while playing some potentially dangerous sport and riding a bicycle
• Using seat belts while driving
• Avoiding excessive use of drug and alcohol
• Prompt treatment of brain infections, to minimize damage caused by swelling
• Seeking immediate medical attention for conditions like strokes, transient ischemic attacks and brain aneurysms

Anterograde Amnesia Support Group

A number of forums and organizations have been established to provide facts and information regarding the proper management of the disorder. These include:

The Brain Injury Association of America

1608 Spring Hill Road, Suite 110

Vienna, Virginia 22182

Phone: 703-761-0750

Fax: 703-761-0755

Website: http://www.biausa.org/index.htm

The Alzheimer’s Association

225 N. Michigan Ave., Fl. 17

Chicago, Illinois 60601-7633

Phone: 312-335-8700

Fax: 1-866-699-1246

E-mail: [email protected]

Website: http://www.alz.org/index.asp

Anterograde Amnesia is one of the main forms of Amnesia occurring due to a wide range of factors. Individuals suffering from the disorder require constant support from their families and friends in order to cope with the condition.

References:

http://www.buzzle.com/articles/anterograde-amnesia.html

http://www.agemattersclinic.com/What-is-Anterograde-Amnesia.php

http://www.wisegeek.com/what-is-anterograde-amnesia.htm

http://www.human-memory.net/disorders_anterograde.html

http://www.simplypsychology.org/anterograde-amnesia.html