Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Original Paper Audiol Neurotol 2013;18:114–124 DOI: 10.1159/000345643 Head-Shaking Aids in the Diagnosis of Acute Audiovestibular Loss due to Anterior Inferior Cerebellar Artery Infarction Young Eun Huh a Ja-Won Koo b Hyung Lee c Ji-Soo Kim a Departments of a Neurology and b Otolaryngology, Head and Neck Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam-si, and c Department of Neurology, Keimyung University School of Medicine, Daegu, South Korea the flocculus was relatively frequent in patients with pervert- ed 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. Copyright © 2012 S. Karger AG, Basel Introduction Infarction involving the anterior inferior cerebellar artery (AICA) territory usually manifests with acute au- diovestibular loss. As the AICA supplies both peripheral labyrinth and central vestibular structures [Amarenco and Hauw, 1990; Amarenco et al., 1993], the vestibular symptoms and signs in AICA infarction may result from both peripheral and central vestibular lesions. However, since peripheral vestibular signs prevail in combined cen- tral and peripheral vestibular dysfunction, diagnosis of AICA infarction remains a challenge, especially when other neurological symptoms and signs are absent or not prominent. In this regard, head-shaking may be a useful bedside maneuver in diagnosing AICA infarction since it can detect central as well as peripheral pathology. Key Words Vertigo  Nystagmus  Anterior inferior cerebellar artery  Vestibulopathy  Stroke Abstract Objective: To determine the patterns and diagnostic value of head-shaking nystagmus (HSN) in patients with acute au- diovestibular loss. Method: Eighteen patients underwent evaluation of spontaneous nystagmus, gaze-evoked nystag- mus, HSN, head impulse test, ocular tilt reaction, subjective visual vertical, bithermal caloric tests, and pure-tone audio- gram. 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 abnor- mal head impulse testing (n = 3). Overall, central HSN, gaze- evoked nystagmus, and normal head impulse testing were specific for anterior inferior cerebellar artery (AICA) infarc- tion. Moreover, central HSN was the only sign that indicated stroke in 1 of our patients with isolated audiovestibular syn- drome. Lesion subtraction analyses revealed that damage to Received: April 12, 2012 Accepted after revision: November 4, 2012 Published online: December 28, 2012 Neurotology Audiology Ji-Soo Kim, MD, PhD Department of Neurology, College of Medicine, Seoul National University Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu Seongnam-si 463-707 (South Korea) E-Mail jisookim  @  snu.ac.kr © 2012 S. Karger AG, Basel 1420–3030/13/0182–0114$38.00/0 Accessible online at: www.karger.com/aud