Causes of transient global amnesia include intense physical activity, overwork, a sudden plunge into hot or cold water, a mild injury to the head and medical procedures, according to Mayo Clinic. People can also experience transient global amnesia as the result of an emotional shock.
Other causes of transient global amnesia include congestion in the patient's veins, constriction of blood vessels because of hyperventilation and arterial thromboembolic ischaemia, according to the National Institutes of Health. Arterial thromboembolic ischaemia occurs when a blood clot in an artery temporarily cuts off the supply of oxygen, explains MedicineNet. Other causes of transient global amnesia include straining during bowel movement and severe pain, notes the National Institutes of Health.
During an episode of transient global amnesia, the patient is able to think clearly and pay attention but questions a witness repeatedly because he doesn't remember where he is or how he arrived at his current location, reports Mayo Clinic. When the attack is over, the patient has no memory of it.
An episode of transient global amnesia usually lasts between one and eight hours, adds the National Institutes of Health. Transient global amnesia strikes people between ages 40 and 80 and attacks males and females equally.