title: On the relationship between degree of hand-preference and degree of language lateralization.
abstract: Language lateralization and hand-preference show inter-individual variation in the degree of lateralization to the left- or right, but their relation is not fully understood. Disentangling this relation could aid elucidating the mechanisms underlying these traits. The relation between degree of language lateralization and degree of hand-preference was investigated in extended pedigrees with multi-generational left-handedness (n=310). Language lateralization was measured with functional Transcranial Doppler, hand-preference with the Edinburgh Handedness Inventory. Degree of hand-preference did not mirror degree of language lateralization. Instead, the prevalence of right-hemispheric and bilateral language lateralization rises with increasing strength of left-handedness. Degree of hand-preference does not predict degree of language lateralization, thus refuting genetic models in which one mechanism defines both hand-preference and language lateralization. Instead, our findings suggest a model in which increasing strength of left-handedness is associated with increased variation in directionality of cerebral dominance.
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: M.Somers@umcutrecht.nl.
authors.forename: Metten
authors.initials: M
authors.lastname: Somers
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Maartje F
authors.initials: MF
authors.lastname: Aukes
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Human Genetics, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, USA; Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA.
authors.forename: Roel A
authors.initials: RA
authors.lastname: Ophoff
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Marco P
authors.initials: MP
authors.lastname: Boks
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Willemien
authors.initials: W
authors.lastname: Fleer
authors.affiliation: Department of General Practice, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Kees C L
authors.initials: KC
authors.lastname: de Visser
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: René S
authors.initials: RS
authors.lastname: Kahn
authors.affiliation: Brain Center Rudolf Magnus, Department of Psychiatry, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Iris E
authors.initials: IE
authors.lastname: Sommer
mesh_terms: D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007802:Language; D008297:Male; D008959:Models, Neurological
keywords: Asymmetry; Functional transcranial Doppler; Hand-preference; Language lateralization; Left-handedness