fMRI PANEL OF VERBAL FLUENCY, AUDITORY AND READING COMPREHENSION TASKS IDENTIFIES LANGUAGE DOMINANCE COMPARED TO THE INTRACAROTID AMYTAL TEST
Abstract number :
1.244
Submission category :
Year :
2002
Submission ID :
44
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
William Davis Gaillard, Lyn M. Balsamo, Ben Xu, Bonnie C. Sachs, Phillip L. Pearl, Joan A. Conry, Steven Weinstein, Jay Salpekar, Bahman Jabbari, Carol Frattali, Leonid Kopylev, Susumu Sato, William H. Theodore. Neurology, Children[ssquote]s National Medi
RATIONALE: fMRI language tasks readily identify language areas but some individual studies disagree with IAT. We examined whether a panel of fMRI tasks increases yield in determining hemisphere dominance for language.
METHODS: We studied 26 patients (22 right handed, three left handed, one ambidextrous; 13 male, 13 female) aged 12-56 years, with temporal lobe epilepsy using whole brain 1.5T fMRI (EPI BOLD) with three tasks: Verbal Fluency (Letters); Reading Comprehension; and Auditory Comprehension. Tasks were covert and unmonitored with silent rest control conditions and performed using a boxcar design with six cycles. Data were analyzed with a region of interest analysis from t-maps. The number of activated voxels was determined in inferior frontal gyrus (IFG), mid-frontal gyrus (MFG), and Wernicke[ssquote]s area, using a semi-automated program. An asymmetry index (AI) was calculated [(L-R)/(L+R)] for each region at t=4. fMRI language laterality was defined as: left, AI [gt]0.20; right AI [lt]-0.20; bilateral, |AI|[lt]0.20; non diagnostic [lt]4 voxels in each ROI. fMRI t maps were also visually rated. All patients had confirmation of language lateralization by intra-carotid amytal test (IAT) or surgery.
RESULTS: The fMRI task panel provided language lateralization in temporal regions in 24 (92%) patients and frontal regions in 26 (100%) patients. Eight of 78 (10%) individual studies were non-diagnostic. fMRI showed left dominance in 23 patients, right dominance in two, and bilateral in one. IAT showed left dominance in 22, right in two, bilateral in one, and was non-diagnostic in one. Of the 25 diagnostic IATs, there was agreement between IAT and fMRI in 22 of 25 patients; and partial agreement in the other three: IAT was left and fMRI bilateral in two patients; and IAT bilateral and fMRI left dominant in one. Agreement between IAT and fMRI was 0.70 (Cramer V; p[lt] 0.001). In the three pateints with incomplete agreement between IAT and fMRI, the fMRI panel showed consistent findings across paradigms.
CONCLUSIONS: A fMRI language paradigm panel identifies frontal and temporal language cortex and is useful for determining language dominance partial epilepsy patients. A panel of tasks mitigates likelihood of non-diagnostic findings, helps confirm fMRI results, and may provide information not available with IAT.
[Supported by: NINDS K08 NS 1663
Board of Lady Visitors, Children[ssquote]s National Medical Center
Epilepsy Foundation of America]