Anterograde Amnesia – Explanation and Types

The term anterograde amnesia refers to a selective memory deficit characterized by the inability to create new memories after an incident. Therefore people affected by this type of amnesia are usually unable to remember recent events. But the long term memories before the incident are left intact.

The interesting is that anterograde amnesia is not affecting habits or skill memories. Therefore a person affected by anterograde amnesia might learn new skill which he will remember the next day though he won’t remember the events that occurred the other day.

Retrograde Anterograde Amnesia After Brain Injury:

That’s mostly because the skill and habit memories (procedural memories) are stored in cerebellum while the episodic memories are stored into the cortex.

Other symptoms might include disorientation, confusion and confabulation; the person remembers invented memories.

Research is underway as the mechanism of it is not understood very well yet.

There are two important causes for the anterograde amnesia: benzodiazepine drugs or traumatic brain injury.

There are also rare cases when the anterograde amnesia is caused by illness. Herpes encephalitis for example, if left untreated for four days might lead to damage to the hippocampus leading to anterograde amnesia.

Sometimes patients with certain illnesses have parts of their brain removed to prevent a more serious disorder. For example people with severe seizures might have one or both sides removed. Patients with brain tumors also might have parts of the brains removed.

Strokes can also lead to anterograde deficits as they involve temporal cortex and the temporal lobe.

Alcohol intoxication is another possible cause of the anterograde amnesia. The phenomenon is known as blackout. Studies showed when people drink large amounts of alcohol very fast. The effect is stronger and more likely to occur when the alcohol is ingested on an empty stomach.

Also lack of oxygen can lead to anterograde amnesia as well. Sometimes it can be caused by respiratory distress, carbon monoxide poisoning or heart attack.

Anyone who encounters unexplained memory loss should call a doctor immediately. Sometimes someone else has to call the ambulance as a person with anterograde amnesia might not be able to tell where he is and might not have the spirit presence to call a doctor.

Before seeing a doctor people who experience memory loss should be well prepared. First and for most they should go there accompanied by a friend or a member of the family. Also they should write down all the symptoms as they happen and write down all the important personal details and information as well as the medications that were recently used.

In case of memory loss the doctor will have to make a detailed evaluation which will include a medical history (family history of neurological diseases; depression, headaches, seizures or cancer), alcohol and drugs used (if any), type of memory loss, triggering factors and evolution.

Then the doctor might do a physical exam to check the neurological functions such as reflexes, balance or sensory functions. Then a cognitive test might be useful and the person’s judgment, thinking as well as long and short term memory will be tested.

Imaging tests might include CT scan, MRI and blood tests.

So far there’s no medication to treat anterograde amnesia.