You have visited the emergency department or neurologist in the hospital. The doctor spoke to you about your sudden loss of memory, called ‘Transient Global Amnesia’.
It happens to 5-10 people per 100.000 persons every year, and to 23.5 to 32 per 100,000 per year among those 50 years and older. The majority of episodes occur in individuals between the ages of 50 and 80 years, with a mean age of onset between 60 and 65 years, women are affected slightly more often than men.
For you and people around you the episode of memory loss can be very frightening. Luckily, in general symptoms only last a short while. This folder aims to explain to you what has happened.
Transient Global Amnesia
Global Amnesia means loss of memory. When this loss of memory happens suddenly, and gets better quickly, we refer to this as Transient Global Amnesia. Though the loss of memory may be frightening, in general memory restores in less than 24 hours without any residual symptoms. Even though your ability to store new memories will return quickly, your memories for events during the attack in general do not return.
During the attack, the loss of memory may be ‘anterograde’, describing the inability to form new memories, as well as ‘retrograde’ meaning a loss of memory for a period of time before the attack. You may not, for instance, remember speaking to people or other events several days or weeks before the attack. Because of the anterograde amnesia, no new memories are formed for the duration of the attack, causing a gap in your memory once the attack subsides. Usually, the retrograde amnesia restores itself and memories from before the attack will return with time.
During the attack, patients may be frightened, agitated, and confused. Patients tend to ask the same questions over and over, often in an identical manner. The answers to these questions are forgotten within seconds to minutes. Often heard questions are ‘Where are we?’ or ‘How did I get here?’. Patients often wonder about the time when seeing a clock ‘Is it three O’clock already?’ since they do not remember time passing. During the attack, the ability to recognise family or loved ones is not impaired, and older memories are still intact. People know who they are, and where they live for instance. The ability to move or speak also remains intact. After symptoms subside, patients may suffer a slight headache and experience problems concentrating for up to several weeks.
The cause of Transient Global Amnesia remains largely unknown. In some cases (up to 50%), symptoms may be preceded by physical effort (e.g. lifting shopping bags), (emotional) stress, coughing, or pain. Sometimes changes of temperature can pose as a trigger for the attack, especially changes from warm to cold. People with a history of migraines have a higher risk of Transient Global Amnesia.
It is important to know that Transient Global Amnesia is not a form of stroke and people suffering Transient Global Amnesia do not have an increased risk of cardiovascular diseases compared to other individuals.
In general, patients will only suffer Transient Global Amnesia once and recurrence is rare. The average recurrence rate is estimated to be 3-5% per year. Transient global amnesia has no direct complications, but it can cause emotional distress. If you have an episode, the gap in your memory can be unsettling, and you're likely to worry about a recurrence. Also, a symptom as dramatic as memory loss often indicates a serious underlying disease. Transient global amnesia is an exception, but it can be hard to let go of the fear that you have a tumor or had a stroke.
If you need reassurance, ask your doctor to go over the results of your neurological exam and diagnostic tests with you. A counsellor or psychotherapist can help you deal with persistent anxiety.