Transient global amnesia (TGA) is a neurological disorder whose key defining characteristic is a temporary but almost total disruption of short-term memory with a range of problems accessing older memories. A person in a state of TGA exhibits no other signs of impaired cognitive functioning but recalls only the last few moments of consciousness, as well as possibly a few deeply encoded facts of the individual's past, such as their childhood, family, or home perhaps.
Both TGA and anterograde amnesia deal with disruptions of short-term memory. However, a TGA episode generally lasts no more than 2 to 8 hours before the patient returns to normal with the ability to form new memories. A patient with anterograde amnesia may not be able to form new memories indefinitely.