title: Functional MRI, DTI and neurophysiology in horizontal gaze palsy with progressive scoliosis.
abstract: BACKGROUND
  Horizontal gaze palsy with progressive scoliosis (HGPPS) is an autosomal recessive disease due to a mutation in the ROBO3 gene. This rare disease is of particular interest because the absence, or at least reduction, of crossing of the ascending lemniscal and descending corticospinal tracts in the medulla predicts abnormal ipsilateral sensory and motor systems.
  
  
  METHODS
  We evaluated the use of functional magnetic resonance imaging (fMRI) for the first time in this disease and compared it to diffusion tensor imaging (DTI) tractography and neurophysiological findings in the same patient with genetically confirmed ROBO3 mutation.
  
  
  RESULTS
  As expected, motor fMRI, somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) were dominantly ipsilateral to the stimulation side. DTI tractography revealed ipsilateral ascending and descending connectivity in the brainstem yet normal interhemispheric connections in the corpus callosum. Auditory fMRI revealed bilateral auditory activation to monaural left-sided auditory stimulation. No significant cortical activation was observed after monaural right-sided stimulation, a hearing defect having been excluded. Prosaccades fMRI showed no activations in the eye-movement network.
  
  
  CONCLUSIONS
  Motor fMRI confirmed the established findings of DTI and neurophysiology in the same patient. In suspected HGPPS, any technique appears appropriate for further investigation. Auditory fMRI suggests that a monaural auditory system with bilateral auditory activations might be a physiological advantage as compared to a binaural yet only unilateral auditory system, in analogy to anisometropic amblyopia. Moving-head fMRI studies in the future might show whether the compensatory head movements instead of normal eye movements activate the eye-movement network.
authors.affiliation: Institute of Radiology, Department of Neuroradiology, University Hospital Basel, Basel, Switzerland. shaller@uhbs.ch
authors.forename: Sven
authors.initials: S
authors.lastname: Haller
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Wetzel
authors.forename: Jürg
authors.initials: J
authors.lastname: Lütschg
mesh_terms: D000293:Adolescent; D019054:Evoked Potentials, Motor / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015835:Ocular Motility Disorders / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D011712:Pyramidal Tracts / Q000473:pathology; D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic / Q000235:genetics; D012600:Scoliosis / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D000097905:Roundabout Proteins
chemical_list: D011956:Receptors, Cell Surface; D011971:Receptors, Immunologic; C499630:ROBO3 protein, human; D000097905:Roundabout Proteins