501. Is language lateralization in temporal lobe epilepsy patients related to the nature of the epileptogenic lesion?
- Author
-
Briellmann RS, Labate A, Harvey AS, Saling MM, Sveller C, Lillywhite L, Abbott DF, and Jackson GD
- Subjects
- Adult, Age of Onset, Brain Mapping, Brain Neoplasms congenital, Brain Neoplasms physiopathology, Epilepsy, Temporal Lobe pathology, Female, Frontal Lobe pathology, Frontal Lobe physiopathology, Hippocampus pathology, Humans, Image Processing, Computer-Assisted, Male, Sclerosis, Cerebral Cortex pathology, Cerebral Cortex physiopathology, Epilepsy, Temporal Lobe diagnosis, Epilepsy, Temporal Lobe physiopathology, Functional Laterality physiology, Language, Magnetic Resonance Imaging statistics & numerical data
- Abstract
Purpose: Early acquired lesions are considered to be a risk factor for atypical language lateralization in epilepsy, whereas developmental lesions are not. Hippocampal sclerosis (HS) can be understood as an early, acquired lesion, whereas developmental tumors (DT) are thought to originate in utero. We assessed whether language lateralization differs between these groups of temporal lobe epilepsy patients., Methods: We used 3-Tesla functional MRI (fMRI) to assess 41 patients (16 DT, 25 HS) and 50 controls, performing a noun-verb-generation task. fMRI data were processed by using SPM2. A laterality index (LI) was calculated based on the number of activated voxels in left- and right-sided frontal lobe language areas. Atypical lateralization was considered if the index was < or = 0.2., Results: Patients had a lower LI (0.42 +/- 0.5) than controls (0.6 +/- 0.3; p < or = 0.05), but the LI was not different between DT (0.44 +/- 0.5) and HS patients (0.43 +/- 0.4; p = 0.9). The frequency of atypical lateralization was increased in patients (27%) compared with controls (8%) but was similar in both patient groups (DT, 31%; HS, 24%). HS patients had an earlier onset and longer duration of epilepsy and a higher frequency of significant antecedent events (p < or = 0.05)., Conclusions: Patients with TLE demonstrate a deviation toward atypical language lateralization. However, language lateralization was not different between patients with presumably acquired lesions compared with patients with developmental pathology. This suggests that the nature of the temporal lobe lesion does not influence overall language lateralization.
- Published
- 2006
- Full Text
- View/download PDF