Language dominance in partial epilepsy patients identified with an fMRI reading task.
BACKGROUND
fMRI language tasks readily identify frontal language areas; temporal activation has been less consistent. No studies have compared clinical visual judgment to quantitative region of interest (ROI) analysis.


OBJECTIVE
To identify temporal language areas in patients with partial epilepsy using a reading paradigm with clinical and ROI interpretation.


METHODS
Thirty patients with temporal lobe epilepsy, aged 8 to 56 years, had 1.5-T fMRI. Patients silently named an object described by a sentence compared to a visual control. Data were analyzed with ROI analysis from t-maps. Regional asymmetry indices (AI) were calculated ([L-R]/[L+R]) and language dominance defined as >0.20. t-Maps were visually rated by three readers at three t thresholds. Twenty-one patients had intracarotid amobarbital test (IAT).


RESULTS
The fMRI reading task provided evidence of language lateralization in 27 of 30 patients with ROI analysis. Twenty-five were left dominant, two right, one bilateral, and two were nondiagnostic; IAT and fMRI agreed in most patients, three had partial agreement, none overtly disagreed. Interrater agreement ranged between 0.77 to 0.82 (Cramer V; p < 0.0001); agreement between visual and ROI reading with IAT was 0.71 to 0.77 (Cramer V; p < 0.0001). Viewing data at lower thresholds added interpretation to 12 patients on visual analysis and 8 with ROI analysis.


CONCLUSIONS
An fMRI reading paradigm can identify language dominance in frontal and temporal areas. Clinical visual interpretation is comparable to quantitative ROI analysis.
Department of Neurosciences, Children's National Medical Center, George Washington University School of Medicine, Washington, DC, USA. gaillardw@ninds.nih.gov
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Gaillard
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Balsamo
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Xu
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Grandin
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Braniecki
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Papero
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Weinstein
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Conry
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Pearl
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Sachs
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Sato
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Jabbari
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Vezina
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Frattali
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Theodore
D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011597:Psychomotor Performance; D011932:Reading