title: Corticobulbar tract changes as predictors of dysarthria in childhood brain injury.
abstract: OBJECTIVE
  To identify corticobulbar tract changes that may predict chronic dysarthria in young people who have sustained a traumatic brain injury (TBI) in childhood using diffusion MRI tractography.
  
  
  METHODS
  We collected diffusion-weighted MRI data from 49 participants. We compared 17 young people (mean age 17 years, 10 months; on average 8 years postinjury) with chronic dysarthria who sustained a TBI in childhood (range 3-16 years) with 2 control groups matched for age and sex: 1 group of young people who sustained a traumatic injury but had no subsequent dysarthria (n = 15), and 1 group of typically developing individuals (n = 17). We performed tractography from spherical seed regions within the precentral gyrus white matter to track: 1) the hand-related corticospinal tract; 2) the dorsal corticobulbar tract, thought to correspond to the lips/larynx motor representation; and 3) the ventral corticobulbar tract, corresponding to the tongue representation.
  
  
  RESULTS
  Despite widespread white matter damage, radial (perpendicular) diffusivity within the left dorsal corticobulbar tract was the best predictor of the presence of dysarthria after TBI. Diffusion metrics in this tract also predicted speech and oromotor performance across the whole group of TBI participants, with additional significant contributions from ventral speech tract volume in the right hemisphere.
  
  
  CONCLUSIONS
  An intact left dorsal corticobulbar tract seems crucial to the normal execution of speech long term after acquired injury. Examining the speech-related motor pathways using diffusion-weighted MRI tractography offers a promising prognostic tool for people with acquired, developmental, or degenerative neurologic conditions likely to affect speech.
authors: Developmental Cognitive Neuroscience Unit, UCL Institute of Child Health, London, UK. Liégeois:F.Liegeois@ucl.ac.uk
authors: Frédérique
authors: F
authors: Liégeois
authors: Jacques-Donald
authors: JD
authors: Tournier
authors: Lauren
authors: L
authors: Pigdon
authors: Alan
authors: A
authors: Connelly
authors: Angela T
authors: AT
authors: Morgan
mesh_terms: D000293:Adolescent; D001930:Brain Injuries / Q000150:complications / Q000473:pathology*; D002648:Child; D056324:Diffusion Tensor Imaging; D004401:Dysarthria / Q000209:etiology / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D009434:Neural Pathways / Q000473:pathology*; D011712:Pyramidal Tracts / Q000473:pathology*