Mnestic deficits represent the core
cognitive impairment of patients with
temporal lobe epilepsy (TLE), irrespective of the existence of overt morphological
lesions. Compared to controls, patients with
symptomatic TLE show altered functional
activation patterns in
fMRI studies on
memory processes. But, so far, such studies have rarely investigated patients with
temporal lobe epilepsy of unknown cause. Therefore, in the current study, a small sample of 6 right TLE patients with normal structural
MRIs was compared to controls
with respect to brain activity during encoding of face-name associations using
fMRI. Compared to controls, patients retrieved fewer face-name associations correctly, but showed significantly greater
activation of the affected
hippocampus for successfully encoded stimuli. Therefore, higher
hippocampal activation seems necessary for successful encoding of associations in patients compared to controls. But, this process is not entirely successful since the patients cannot achieve the same performance as controls. In conclusion, the
hyperactivation of the
hippocampus might represent a compensational but inefficient process.
