title: Acute VOR gain differences for outward vs. inward head impulses.
abstract: BACKGROUND
  Vestibular rehabilitation is a sub-specialization within the practice of physical therapy that includes treatments designed to reduce gaze instability. Gaze stability exercises are commonly given for head rotations to the left and right, even in subjects with one healthy vestibular system (as in unilateral loss). Few studies have investigated the difference in the angular vestibular ocular reflex gain (aVOR) measured in the acute phase after deafferentation for ipsilesional head rotations that move the head away from center or towards center.
  
  
  OBJECTIVE
  The purpose of this study was to compare differences in acute aVOR gain when the head was passively rotated outward from an initially centered position (neck neutral) versus the head being rotated inward.
  
  
  METHODS
  We recorded head and eye velocity using video head impulse test equipment in patients with unilateral vestibular pathology scheduled for tumor resection via retrosigmoid approach (n=5) or labyrinthectomy due to Meniere's disease (n=2).
  
  
  RESULTS
  We found 1) no difference in the ipsilesional aVOR gain for inward or outward directed head impulse rotations and 2) head velocity is inversely correlated with aVOR gain for ipsilesional but not contralesional rotations.
  
  
  CONCLUSIONS
  Bedside testing of the ipsilesional aVOR following acute vestibular ablation can be done with head impulse rotations to either side. In the acute stages, physical therapists should prescribe ipsilesional and contralesional gaze stability exercises.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, USA Department of Physical Medicine and Rehabilitation, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Schubert
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Georgios
authors.initials: G
authors.lastname: Mantokoudis
authors.affiliation: Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Agrawal
mesh_terms: D000328:Adult; D000368:Aged; D005133:Eye Movements / Q000502:physiology; D005260:Female; D064087:Head Impulse Test; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery; D009759:Nystagmus, Pathologic / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery; D013506:Otologic Surgical Procedures; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012399:Rotation; D015837:Vestibular Diseases / Q000503:physiopathology / Q000534:rehabilitation / Q000601:surgery; D014722:Vestibule, Labyrinth / Q000502:physiology
keywords: Head impulse test; VOR gain; vestibular rehabilitation