Transient global amnesia (TGA) is a condition that results in sudden, albeit temporary, memory loss that is concurrent with no established diagnosis of a neurological condition, such as stroke or epilepsy. When broken down into its parts, the phrase TGA is highly accurate: transient, as in fleeting or temporary; global, meaning all; amnesia, referring to loss of memory, or forgetting. According to the Mayo Clinic, when a TGA occurs, you spontaneously forget recent events, including where you currently are and how you got there. You may be disoriented and frightened. You do remember who you are but will often be unable to relate details of the past few days, months or even years. Because short-term memory is often involved, you may be left unable to form new memories for a day or two, an accompanying condition known as anterograde amnesia. Once the TGA episode has passed, however, your memory returns unscathed, and there is evidence that spontaneous TGAs rarely happen twice to the same person.
Per the Mayo Clinic, causes of TGA can vary. There is some evidence that sudden, radical temperature changes in the body can trigger an amnesiac event, like suddenly being immersed in very hot or very cold water. There is also evidence that acute emotional stress, such as the death of a loved one, can cause the TGA. While the underlying causes are actually unknown, tracing the pathology of the TGA has resulted in evidence being gathered that indicates even sexual intercourse can cause an event, as can acute pain. In a study done at UCLA, patients with TGA usually average around age 60, with outlying age parameters of anywhere from 40 to 80 years. The study further states that other causes must be examined if a patient under 40 years of age experiences what appears to be TGA.
According to Dr. Bruce Landres of UCLA, transient global amnesia tends to be resolved on its own with very low chance of it ever happening again. Should your memory loss persist for more than 24 to 48 hours, contact your doctor, as this could be an indicator of a more serious or permanent memory loss. Lengthy recovery time from the TGA could also indicate the presence of epilepsy or possibly an injury to the brain itself. One example of this would be blood pooling in the brain, known as intracranial bleed.