A simple magnetoencephalographic auditory paradigm may aid in confirming left-hemispheric language dominance in epilepsy patients

• DOI: 10.1371/journal.pone.0200073
• Publication Date: 2018-07-02T17:57:23Z
• Authors: Juha Wilenius; Henri Lehtinen; Ritva Paetau; Riitta Salmelin; Erika Kirveskari
• Keywords: Magnetoencephalography; Wada test; Amobarbital; Dominance (genetics); Electrocorticography

The intracarotid amobarbital procedure (IAP) is the current "gold standard" in preoperative assessment of language lateralization epilepsy surgery candidates. It is, however, invasive and has several limitations. Here we tested a simple noninvasive test performed with magnetoencephalography (MEG).We recorded auditory MEG responses to pairs vowels pure tones 16 candidates who had undergone IAP. For each individual, selected pair planar gradiometer sensors strongest N100m response hemisphere and-from vector sum signals this pair-calculated vowel/tone amplitude ratio left (L) right (R) and, subsequently, laterality index: LI = (L-R)/(L+R). In addition analysis using single sensor pair, an alternative was averaged over 18 temporal both hemispheres.The index did not correlate significantly data obtained from However, pattern stronger than associated left-hemispheric dominance IAP all six patients showed pattern. This results specificity 100% sensitivity 67% predicting (p 0.01, Fisher's exact test). channels, one additional patient left-dominant particular pattern, increasing 78% 0.003).This paradigm shows promise feasibly noninvasively confirming may aid reducing need for IAP, if are confirmed larger samples.