title: Beyond Dizziness: Virtual Navigation, Spatial Anxiety and Hippocampal Volume in Bilateral Vestibulopathy.
abstract: Bilateral vestibulopathy (BVP) is defined as the impairment or loss of function of either the labyrinths or the eighth nerves. Patients with total BVP due to bilateral vestibular nerve section exhibit difficulties in spatial memory and navigation and show a loss of hippocampal volume. In clinical practice, most patients do not have a complete loss of function but rather an asymmetrical residual functioning of the vestibular system. The purpose of the current study was to investigate navigational ability and hippocampal atrophy in BVP patients with residual vestibular function. Fifteen patients with BVP and a group of age- and gender- matched healthy controls were examined. Self-reported questionnaires on spatial anxiety and wayfinding were used to assess the applied strategy of wayfinding and quality of life. Spatial memory and navigation were tested directly using a virtual Morris Water Maze Task. The hippocampal volume of these two groups was evaluated by voxel-based morphometry. In the patients, the questionnaire showed a higher spatial anxiety and the Morris Water Maze Task a delayed spatial learning performance. MRI revealed a significant decrease in the gray matter mid-hippocampal volume (Left: p = 0.006, Z = 4.58, Right: p < 0.001, Z = 3.63) and posterior parahippocampal volume (Right: p = 0.005, Z = 4.65, Left: p < 0.001, Z = 3.87) compared to those of healthy controls. In addition, a decrease in hippocampal formation volume correlated with a more dominant route-finding strategy. Our current findings demonstrate that even partial bilateral vestibular loss leads to anatomical and functional changes in the hippocampal formation and objective and subjective behavioral deficits.
authors.affiliation: German Center for Vertigo and Balance DisordersMunich, Germany; Department of Neurology, Ludwig-Maximilians UniversityMunich, Germany.
authors.forename: Olympia
authors.initials: O
authors.lastname: Kremmyda
authors.affiliation: Department of Psychiatry, Medical University Innsbruck Innsbruck, Austria.
authors.forename: Katharina
authors.initials: K
authors.lastname: Hüfner
authors.affiliation: German Center for Vertigo and Balance Disorders Munich, Germany.
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Flanagin
authors.affiliation: Department of Psychology, University of New Mexico Albuquerque, NM, USA.
authors.forename: Derek A
authors.initials: DA
authors.lastname: Hamilton
authors.affiliation: Institute for Diagnostic and Interventional Neuroradiology, University Hospital Carl Gustav Carus Dresden, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Linn
authors.affiliation: German Center for Vertigo and Balance DisordersMunich, Germany; Department of Neurology, Ludwig-Maximilians UniversityMunich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Strupp
authors.affiliation: German Center for Vertigo and Balance DisordersMunich, Germany; Department of Acute Neurology, Schön Klinik Bad AiblingBad Aibling, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Jahn
authors.affiliation: German Center for Vertigo and Balance DisordersMunich, Germany; Institute for Clinical Neurosciences, Ludwig-Maximilians UniversityMunich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brandt
keywords: hippocampal atrophy; loss of vestibular function; navigation strategies; spatial anxiety; spatial orientation