Several functional MR imaging studies evaluating the lateralisation of linguistic functions in patients who underwent Wada testing have been reported. There is extensive variance in the Laterality index (LI) calculation across the studies, and the optimal calculation method remains unclear. We attempted to calculate the LI in different ways in the same subjects, in order to find the LI calculation method with the highest correlation to the Wada test. Fifteen patients (10 females, 5 males) suffering from medically intractable temporal lobe epilepsy (TLE) (12 left, 3 right) were admitted for the study. The patients underwent a standardized bilateral intracarotid short-acting barbiturate test. Language testing included spontaneous speech, oral comprehension, reading, object and picture naming, and repetition. All the tasks were scored separately in order to increase the possibility of correlation between Wada and LI. A silent phonemic verbal fluency task (VFT) was used as a language paradigm for functional measurement. Regions of interest (ROIs), with a known association with language function (Broca's area, the lateral prefrontal cortex, etc.), were defined. First, the LIs were calculated from the ROIs using a previously reported method (simple suprathreshold count). Next, we used several new methods of LI calculation (t-weighting of voxels, methods independent of the choice of the statistical threshold, etc.) The most significant correlation with Wada was proven in the LIs that were evaluated from Broca's area (up to R = 0.94, P = 1 x 10(-7)). However, the new LI calculation methods used in the present study did not produce a statistically significant benefit in comparison to previously reported methods.

Department of Neurology Masaryk University St Anne's University Hospital Pekarská 53 Brno 65691 Czech Republic

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Arch Neurol. 1984 Oct;41(10):1077-80 PubMed

Neurology. 1999 Mar 10;52(4):798-809 PubMed

Neuroradiology. 2002 Jun;44(6):467-74 PubMed

Brain Cogn. 1997 Feb;33(1):118-32 PubMed

Brain. 1999 Nov;122 ( Pt 11):2033-46 PubMed

AJNR Am J Neuroradiol. 2001 Oct;22(9):1711-8 PubMed

Brain. 2004 Jun;127(Pt 6):1229-36 PubMed

Ann N Y Acad Sci. 1977 Sep 30;299:355-69 PubMed

Brain. 2006 Feb;129(Pt 2):346-51 PubMed

Neuroimage. 2003 Feb;18(2):460-7 PubMed

Ann Neurol. 1990 Nov;28(5):597-613 PubMed

Brain Lang. 1992 Nov;43(4):694-712 PubMed

Brain. 2003 Sep;126(Pt 9):2043-51 PubMed

Stroke. 1987 Nov-Dec;18(6):997-1004 PubMed

Neuroimage. 2002 Sep;17(1):447-60 PubMed

AJNR Am J Neuroradiol. 2001 May;22(5):985-91 PubMed

Neurosci Lett. 2003 Jul 31;346(1-2):109-13 PubMed

Neuroimage. 2003 Feb;18(2):423-38 PubMed

Neuropsychologia. 1990;28(8):831-8 PubMed

Eur J Neurol. 2005 Apr;12(4):268-75 PubMed

J Neurol Neurosurg Psychiatry. 1998 Apr;64(4):492-8 PubMed

J Anat. 2000 Oct;197 Pt 3:335-59 PubMed

Neuroimage. 2006 Mar;30(1):266-71 PubMed

J Neurosci. 1997 Jan 1;17(1):353-62 PubMed

AJNR Am J Neuroradiol. 1995 May;16(5):1087-92 PubMed

Neuropsychologia. 1971 Mar;9(1):97-113 PubMed

Neurology. 2000 Apr 25;54(8):1625-33 PubMed

Neuropsychologia. 1988;26(1):167-72 PubMed

Brain Lang. 2002 Mar;80(3):421-37 PubMed

Epilepsia. 2001 Oct;42(10):1241-54 PubMed