If I remember well, the prognosis is positive
Transient global amnesia is a type of amnesia involving the sudden but temporary disturbance in an otherwise healthy person's memory. There are two main kinds of amnesia: anterograde and retrograde amnesia.
Anterograde amnesia is a type of memory loss associated with a trauma, disease, or emotional events. It is characterized by the inability to remember new information. Retrograde amnesia, as the name suggests, is the loss of distant memories usually preceding a given trauma.
In transient global amnesia, in most cases distant memories and immediate recall are both intact, such as language function, attention, visual and social skills.
However, during the period of amnesia, people suffering from the disorder cannot remember recent occurrences nor can they retain any new visual or verbal information for more than a couple minutes.
Though patients generally remember their identities, they are often very confused by their surroundings and the people around them. They continuously ask questions about events that are transpiring, for example where they are, who is with them, what is happening.
However, once they are told, they immediate forget the answer, and repeat the question again.
The period of amnesia can last from one to 24 hours. Some people suffer from a headache, dizziness, and nausea while others have only memory loss. Once they regain their memory, some people can recall both the episode and the feeling of not being able to remember.
However, others never recover the memories of the attack nor the events immediately before.
The cause of TGA remains unclear. There is evidence that external emotional stresses, such as traffic accident, an attack, sexual intercourse, immersion in cold water, or even extreme exercising in the gym can trigger the loss of memory.
All those activities can affect our brain and put additional stress on it.
For example, TGA may be the result of a transient ischemic attack, also known as a "mini-stroke." Transient ischemic attacks are caused by a temporary interruption of the blood flow to the brain (picture a knockout during fight in the local pub).
Another possible cause of transient global amnesia is a basilar artery migraine, a type of migraine caused by the abnormal constriction and dilatation of vessel walls.
Patients suffering from transient global amnesia have undergone medical imaging techniques, for example magnetic resonance imaging (MRI) and positron emission topography (PT), in order to find out what biological changes cause a temporary lapse in memory.
Some MRIs have shown evidence of changes in the medial temporal lobes, indicating that patients had suffered from a transient ischemic attack.
However, many people that have undergone such tests have not shown any changes in the functioning of their brains.
The good news is that transient global amnesia has a very positive prognosis - its effects are never permanent and the episodes last for a relatively short period of time. Unless memory loss occurs on a regular basis you don't have to worry.
Remember the old saying: "If you are concerned about your memory - you're OK. If everyone around tells you that you have a problem and you are convinced that you haven't - go see the doctor". ■