Side of seizure focus predicts left medial temporal lobe activation during verbal encoding.
OBJECTIVE
Functional MRI (FMRI) was used to investigate the effect of medial temporal lobe (MTL) pathology on activation of language encoding areas in patients with temporal lobe epilepsy (TLE).


METHODS
Whole-brain FMRI was obtained. Twenty-eight patients with either left TLE (LTLE) or right TLE (RTLE) performed a semantic decision task alternating with an auditory perceptual task.


RESULTS
Activation of language areas in the frontal and parietal lobes was similar in both groups, with no group differences in the total number of active voxels. However, the RTLE group showed much stronger activation of the left MTL, including the hippocampus, parahippocampal gyrus, and collateral sulcus, than did the LTLE group.


CONCLUSIONS
Activation of the left MTL during semantic encoding discriminates patients with RTLE and LTLE. This FMRI technique may potentially be of use in determining memory lateralization and for predicting the side of seizure focus in TLE.
Department of Neurology, Medical College of Wisconsin, Milwaukee 53226, USA.
P S
PS
Bellgowan
J R
JR
Binder
S J
SJ
Swanson
T A
TA
Hammeke
J A
JA
Springer
J A
JA
Frost
W M
WM
Mueller
G L
GL
Morris
D000328:Adult; D000368:Aged; D001931:Brain Mapping / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013702:Temporal Lobe / Q000503:physiopathology*; D014706:Verbal Learning / Q000502:physiology*