Long-term versus short-term memory deficits for faces in temporal lobe and generalized epilepsy patients.

It is still an open question whether short-term and long-term memory are two anatomically dissociable memory systems working in parallel or whether they are represented by neural circuits within similar cortical areas. Epilepsy may be used as a model to study these memory processes. We hypothesized that a double dissociation of short-term and long-term memory exists in temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE). Immediate and 24-hour face recognition was tested in 10 TLE patients, 9 IGE patients, and 10 healthy controls. TLE patients' immediate recognition was unimpaired, but their memory scores were reduced as compared to healthy controls after 24 hours. In IGE patients, memory was already reduced during immediate recognition. These results are in line with the idea that short-term memory is a transient trace that requires consolidation supported by the medial temporal lobe to change into a more stable status of long-term memory.