Galvanic ocular vestibular evoked myogenic potentials provide new insight into vestibulo-ocular reflexes and unilateral vestibular loss

OBJECTIVE Synchronous extraocular muscle activity can be recorded from around the eyes at the beginning of a vestibular-evoked eye movement (ocular vestibular evoked myogenic potentials, OVEMPs). As galvanic vestibular stimulation (GVS) evokes the vestibulo-ocular reflex, we wished to investigate GVS-evoked OVEMPs. METHODS We stimulated 10 normals and 6 patients with unilateral vestibular loss (uVL) with bi/unipolar 4 mA, 2 ms current steps at the mastoid. OVEMPs were recorded from electrodes placed superior and inferior to the eyes. RESULTS OVEMPs were present beneath both eyes in all normal subjects: an initial positivity ipsilateral to the cathodal electrode (peak latency 9.9 ms, amplitude 1.3 microV) and an initial negativity contralateral to the cathode (8.8 ms, 2.4 microV). In the patients, stimulation of the affected side produced little or no response. Stimulation of the intact side produced only contralateral responses. CONCLUSIONS The infra-orbital response is likely produced primarily by the inferior obliques, producing conjugate torsion away from the cathode. The projection to the ipsilateral eye depends upon normal vestibular function on the contralateral side. SIGNIFICANCE OVEMPs can be evoked by GVS. While bilateral effects are obtained with unilateral stimulation in normals, the primary vestibular pathway to the inferior oblique in humans is crossed.

[1]  I. Curthoys,et al.  Mechanisms of recovery following unilateral labyrinthectomy: a review , 1989, Brain Research Reviews.

[2]  J. Colebatch,et al.  Ocular vestibular evoked myogenic potentials in superior canal dehiscence , 2007, Journal of Neurology, Neurosurgery, and Psychiatry.

[3]  A. Coats,et al.  The recorded body‐sway response to galvanic stimulation of the labyrinth: A preliminary study , 1969, The Laryngoscope.

[4]  J. Colebatch,et al.  Vestibulocollic reflexes evoked by short‐duration galvanic stimulation in man , 1998, The Journal of physiology.

[5]  G. M. Halmagyi,et al.  Head taps evoke a crossed vestibulo-ocular reflex , 2007, Neurology.

[6]  B. Day,et al.  Short-latency eye movements evoked by near-threshold galvanic vestibular stimulation , 2003, Experimental Brain Research.

[7]  Unsw Clinical.  Vestibular-evoked extraocular potentials produced by stimulation with bone-conducted sound , 2005 .

[8]  T. Brandt,et al.  Ocular torsion and tilt of subjective visual vertical are sensitive brainstem signs , 1993, Annals of neurology.

[9]  R. Leigh,et al.  The neurology of eye movements , 1984 .

[10]  J. Colebatch,et al.  Ocular vestibular evoked myogenic potentials (OVEMPs) produced by air- and bone-conducted sound , 2007, Clinical Neurophysiology.

[11]  S. Iwasaki,et al.  Vestibular-evoked extraocular potentials by air-conducted sound: Another clinical test for vestibular function , 2007, Clinical Neurophysiology.

[12]  J. C. Rothwell,et al.  Motor unit excitability changes mediating vestibulocollic reflexes in the sternocleidomastoid muscle , 2004, Clinical Neurophysiology.

[13]  H Shimazu,et al.  Inhibition of central vestibular neurons from the contralateral labyrinth and its mediating pathway. , 1966, Journal of neurophysiology.

[14]  A. Ochiai,et al.  The site of lesion in “vestibular neuritis”: Study by galvanic VEMP , 2003, Neurology.

[15]  Thomas Brandt,et al.  Inverse U-shaped curve for age dependency of torsional eye movement responses to galvanic vestibular stimulation. , 2003, Brain : a journal of neurology.

[16]  J. Colebatch,et al.  Vestibulocollic reflexes: normal values and the effect of age , 2001, Clinical Neurophysiology.

[17]  J. Colebatch,et al.  Ocular vestibular evoked myogenic potentials (OVEMPs) in superior canal dehiscence , 2008, Clinical Neurophysiology.

[18]  John T. Flynn,et al.  Adler's Physiology of the Eye: Clinical Application, 10th ed , 2003 .

[19]  E D Young,et al.  Responses of squirrel monkey vestibular neurons to audio-frequency sound and head vibration. , 1977, Acta oto-laryngologica.

[20]  W. M. Krogman.  The human skeleton in forensic medicine. I. , 1963, Postgraduate medicine.

[21]  I. Curthoys,et al.  Human ocular torsional position before and after unilateral vestibular neurectomy , 2004, Experimental Brain Research.

[22]  Juno Kim,et al.  Responses of primary vestibular neurons to galvanic vestibular stimulation (GVS) in the anaesthetised guinea pig , 2004, Brain Research Bulletin.

[23]  N. Isu,et al.  Commissural effects in the otolith system , 2001, Experimental Brain Research.

[24]  G Michael Halmagyi,et al.  Latency and initiation of the human vestibuloocular reflex to pulsed galvanic stimulation. , 2006, Journal of neurophysiology.

[25]  J. Goldberg,et al.  Relation between discharge regularity and responses to externally applied galvanic currents in vestibular nerve afferents of the squirrel monkey. , 1984, Journal of neurophysiology.

[26]  N. Isu,et al.  Sacculo-ocular reflex connectivity in cats , 2000, Experimental Brain Research.

[27]  T Haslwanter,et al.  Three-dimensional vector analysis of the human vestibuloocular reflex in response to high-acceleration head rotations. II. responses in subjects with unilateral vestibular loss and selective semicircular canal occlusion. , 1996, Journal of neurophysiology.

[28]  M. Aramideh,et al.  Brainstem reflexes: Electrodiagnostic techniques, physiology, normative data, and clinical applications , 2002, Muscle & nerve.

[29]  I S Curthoys,et al.  A clinical sign of canal paresis. , 1988, Archives of neurology.

[30]  M. B. Bender,et al.  XVI Eye Movements from Semicircular Canal Nerve Stimulation in the Cat , 1964, The Annals of otology, rhinology, and laryngology.

[31]  M Dieterich,et al.  Effects of galvanic vestibular stimulation on otolithic and semicircular canal eye movements and perceived vertical. , 1998, Electroencephalography and Clinical Neurophysiology.

[32]  G. M. Halmagyi,et al.  Ocular vestibular evoked myogenic potentials to bone conducted vibration of the midline forehead at Fz in healthy subjects , 2008, Clinical Neurophysiology.

[33]  J. C. Rothwell,et al.  Postural electromyographic responses in the arm and leg following galvanic vestibular stimulation in man , 2004, Experimental Brain Research.

[34]  M. McCue,et al.  Acoustically responsive fibers in the vestibular nerve of the cat , 1994, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[35]  Hamish G. MacDougall,et al.  Linearity, symmetry and additivity of the human eye-movement response to maintained unilateral and bilateral surface galvanic (DC) vestibular stimulation , 2002, Experimental Brain Research.

[36]  I S Curthoys,et al.  Physiological and anatomical study of click-sensitive primary vestibular afferents in the guinea pig. , 1997, Acta oto-laryngologica.

[37]  K Tokumasu,et al.  Eye movements from single utricular nerve stimulation in the cat. , 1969, Acta oto-laryngologica.

[38]  R. Leigh,et al.  The neurology of eye movements , 2006 .

[39]  I. Curthoys,et al.  Click-evoked vestibulo-ocular reflex , 2006, Neurology.

[40]  Hamish G. MacDougall,et al.  Between-subject variability and within-subject reliability of the human eye-movement response to bilateral galvanic (DC) vestibular stimulation , 2002, Experimental Brain Research.

[41]  Juno Kim,et al.  Bone conducted vibration selectively activates irregular primary otolithic vestibular neurons in the guinea pig , 2006, Experimental Brain Research.

[42]  N. Isu,et al.  Utriculoocular reflex arc of the cat. , 1996, Journal of neurophysiology.

[43]  H. Davson.  The Extraocular Muscles and Their Actions , 1990 .

[44]  J. Colebatch,et al.  Selective effects of ageing on vestibular-dependent lower limb responses following galvanic stimulation , 2002, Clinical Neurophysiology.

[45]  Francis Heed Adler,et al.  Adler's Physiology of the eye;: Clinical application , 1976 .

[46]  I. Curthoys,et al.  Ocular Vestibular Evoked Myogenic Potentials in Response to Bone-Conducted Vibration of the Midline Forehead at Fz , 2008, Audiology and Neurotology.