title: Deficits in tongue motor control are linked to microstructural brain damage in multiple sclerosis: a pilot study.
abstract: BACKGROUND
  Deterioration of fine motor control of the tongue is common in Multiple Sclerosis (MS) and has a major impact on quality of life. However, the underlying neuronal substrate is largely unknown. Here, we aimed to explore the association of tongue motor dysfunction in MS patients with overall clinical disability and structural brain damage.
  
  
  METHODS
  We employed a force transducer based quantitative-motor system (Q-Motor) to objectively assess tongue function in 33 patients with MS. The variability of tongue force output (TFV) and the mean applied tongue force (TF) were measured during an isometric tongue protrusion task. Twenty-three age and gender matched healthy volunteers served as controls. Correlation analyses of motor performance in MS patients with individual disease burden as expressed by the Expanded Disability Status Scale (EDSS) and with microstructural brain damage as measured by the fractional anisotropy (FA) on Diffusion Tensor Imaging were performed.
  
  
  RESULTS
  MS patients showed significantly increased TFV and decreased TF compared to controls (p < 0.02). TFV but not TF was correlated with the EDSS (p < 0.04). TFV was inversely correlated with FA in the bilateral posterior limb of the internal capsule expanding to the brain stem (p < 0.001), a region critical to tongue function. TF showed a weaker, positive and unilateral correlation with FA in the same region (p < 0.001).
  
  
  CONCLUSIONS
  Changes in TFV were more robust and correlated better with disease phenotype and FA changes than TF. TFV might serve as an objective and non-invasive outcome measure to augment the quantitative assessment of motor dysfunction in MS.
authors.affiliation: Department of Neurology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany. Fholtbernd@ukaachen.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Holtbernd
authors.affiliation: Department of Neurology, University of Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany. deppe@uni-muenster.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Deppe
authors.affiliation: Department of Radiology, Marienhospital Aachen, Zeise 4, 52066, Aachen, Germany. Rainald.Bachmann@marienhospital.de.
authors.forename: Rainald
authors.initials: R
authors.lastname: Bachmann
authors.affiliation: Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, 12 Queen Square, London, WC1N 3BG, UK. siawooshm@googlemail.com.|Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. siawooshm@googlemail.com.
authors.forename: Siawoosh
authors.initials: S
authors.lastname: Mohammadi
authors.affiliation: Department of Neurology, University of Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany. ringels@uni-muenster.de.
authors.forename: Erich B
authors.initials: EB
authors.lastname: Ringelstein
authors.affiliation: George-Huntington-Institute, Technology Park Muenster, Johann-Krane-Weg 27, 48149, Muenster, Germany.|Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.|Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Reilmann
mesh_terms: D000328:Adult; D016880:Anisotropy; D001933:Brain Stem / Q000473:pathology*; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D020772:Internal Capsule / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology*; D010865:Pilot Projects; D014059:Tongue / Q000503:physiopathology*; D014159:Transducers; D055815:Young Adult