title: Meyer's loop asymmetry and language lateralisation in epilepsy.
abstract: Several studies have suggested an asymmetry in Meyer's loop in individuals, with the left loop anterior to the right. In this study we test the hypothesis that there is an association between Meyer's loop asymmetry (MLA) and language lateralisation.
  
  
  
  57 patients with epilepsy were identified with language functional MRI (fMRI) and diffusion MRI acquisition. Language lateralisation indices from fMRI(LI) and optic radiation and arcuate fasciculus probabilistic tractography was performed for each subject. The subjects were divided into left language dominant (LI>0.4) and non-left language groups (LI<0.4) according to their LI.
  
  
  
  A negative linear correlation was identified between language lateralisation and MLA, with greater left lateralised language associated with more anteriorly placed left Meyer's loops (R value -0.34, p=0.01). There was a significant difference in mean MLA between the two groups, with the left loop being anterior to the right loop in the LI>0.4 group and posterior to the right loop in the LI<0.4 group (p=0.003). No correlation was found between language lateralisation and arcuate fasciculus volume.
  
  
  
  This study suggests an association between the extent of Meyer's loop asymmetry and the lateralisation of language determined by fMRI in patients with epilepsy. Further studies should be carried out to evaluate this association in control subjects and with other measures of language lateralisation.
authors.affiliation: Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Nowell
authors.affiliation: MRI Unit, Epilepsy Society, Chalfont St Peter, UK Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK.
authors.forename: Sjoerd B
authors.initials: SB
authors.lastname: Vos
authors.affiliation: MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: Meneka
authors.initials: M
authors.lastname: Sidhu
authors.affiliation: MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: Kaitlin
authors.initials: K
authors.lastname: Wilcoxen
authors.affiliation: MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: Narek
authors.initials: N
authors.lastname: Sargsyan
authors.affiliation: Translational Imaging Group, Centre of Medical Imaging and Computing, UCL, London, UK.
authors.forename: Sebastien
authors.initials: S
authors.lastname: Ourselin
authors.affiliation: Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK MRI Unit, Epilepsy Society, Chalfont St Peter, UK.
authors.forename: John S
authors.initials: JS
authors.lastname: Duncan
mesh_terms: D000328:Adult; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D059907:Functional Neuroimaging; D005829:Geniculate Bodies / Q000502:physiology*; D006801:Humans; D007802:Language; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult