Reading while moving: The functional assessment of VOR

Issue title: The Vestibular System: A Clinical and Scientific Update in Siena. In honor of Professor Daniele Nuti, Siena, Italy, April 5–6, 2013

Guest editors: Marco Mandalàx, Stefano Ramaty and David S. Zee

Article type: Research Article

Authors: Versino, Maurizio^{a; b; *} | Colagiorgio, Paolo^c | Sacco, Simone^b | Colnaghi, Silvia^d | Quaglieri, Silvia^e | Manfrin, Marco^{e; f} | Benazzo, Marco^{e; f} | Moglia, Arrigo^{a; b} | Ramat, Stefano^c

Affiliations: [a] C. Mondino National Neurological Institute, Pavia, Italy | [b] Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy | [c] Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy | [d] Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy | [e] S.C, di Otorinolaringoiatria Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy | [f] Department of Clinical-Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy | [x] Otological and Skull Base Surgery Department, S.M. delle Scotte Hospital, Siena, Italy | [y] Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy

Correspondence: [*] Corresponding author: Maurizio Versino, Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy. Tel.: +39 0382 380340; Fax: +39 0382 24714; E-mail: mversino@unipv.it

Abstract: The head impulse test (HIT) is nowadays recognized as the gold standard for clinical testing of the angular vestibulo-ocular reflex (VOR). By imposing unpredictable, abrupt head rotations in canal pairs' planes it aims at unveiling the dysfunction of the semicircular canal towards which the head is rotated based on Ewald's II law. Functional testing of the VOR aims at assessing the ability of the reflex to stabilize gaze in space and thus allow clear vision during head movements. The HIT device (HITD) approach exploits impulsive head rotations spawning a range of angular accelerations while requiring subjects to identify optotypes briefly displayed on a screen. Here we also recorded eye movements, so that the evaluation of the individual subject is based both on the VOR gain and on the percentage of correct answers with respect to a population of controls. Here we used the HITD to study 14 patients suffering from vestibular neuritis and 7 of those were re-tested after three months. We found that the HITD was able to unveil the ipsilesional deficit and the contralesional impairment, together with the improvement in the follow-up test.

Keywords: Functional vestibular testing, head impulse test, semicircular canal function, vestibular neuritis

DOI: 10.3233/VES-140531

Journal: Journal of Vestibular Research, vol. 24, no. 5-6, pp. 459-464, 2014