title: Head-shaking aids in the diagnosis of acute audiovestibular loss due to anterior inferior cerebellar artery infarction.
abstract: OBJECTIVE
  To determine the patterns and diagnostic value of head-shaking nystagmus (HSN) in patients with acute audiovestibular loss.
  
  
  METHODS
  Eighteen patients underwent evaluation of spontaneous nystagmus, gaze-evoked nystagmus, HSN, head impulse test, ocular tilt reaction, subjective visual vertical, bithermal caloric tests, and pure-tone audiogram. The findings were compared with those of 21 patients with labyrinthitis.
  
  
  RESULTS
  Fifteen patients (83%) exhibited HSN, and the horizontal HSN usually beat contralesionally (10/14, 71%). However, 9 (50%) patients also showed patterns of central HSN that included perverted HSN (n=7), HSN in the opposite direction of spontaneous nystagmus (n=4), and HSN beating towards unilateral canal paresis or abnormal head impulse testing (n=3). Overall, central HSN, gaze-evoked nystagmus, and normal head impulse testing were specific for anterior inferior cerebellar artery (AICA) infarction. Moreover, central HSN was the only sign that indicated stroke in 1 of our patients with isolated audiovestibular syndrome. Lesion subtraction analyses revealed that damage to the flocculus was relatively frequent in patients with perverted HSN.
  
  
  CONCLUSIONS
  In AICA infarction, HSN was common with both peripheral and central patterns. Careful evaluation of HSN may provide clues for AICA infarction in patients with acute audiovestibular loss.
authors.affiliation: Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si, South Korea.
authors.forename: Young Eun
authors.initials: YE
authors.lastname: Huh
authors.forename: Ja-Won
authors.initials: JW
authors.lastname: Koo
authors.forename: Hyung
authors.initials: H
authors.lastname: Lee
authors.forename: Ji-Soo
authors.initials: JS
authors.lastname: Kim
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002531:Cerebellum / Q000098:blood supply; D003430:Cross-Sectional Studies; D003943:Diagnostic Techniques, Neurological; D005133:Eye Movements / Q000502:physiology; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D020762:Infarction, Posterior Cerebral Artery / Q000175:diagnosis* / Q000503:physiopathology; D007762:Labyrinthitis / Q000175:diagnosis / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000175:diagnosis* / Q000503:physiopathology; D010037:Otolithic Membrane / Q000502:physiology; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology; D014717:Vertigo / Q000175:diagnosis* / Q000503:physiopathology; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000503:physiopathology