title: Transaural linear vestibulo-ocular reflexes from a single utricle.
abstract: To clarify the directional sensitivity of a single utricle with respect to the transaural linear vestibulo-ocular reflex (L-VOR) we studied seven patients before and after vestibular neurectomy. Patients were seated upright in an electrically powered car running on a linear track. Transaural acceleration steps of 0.24 g were applied randomly to the left and right in the dark. The slow phase velocity of the L-VOR was measured from the average of the induced compensatory eye movements. L-VOR asymmetry was calculated as (R-L/R + L x 100) and is < 13% in normals. Before surgery, responses were mostly symmetrical. One week after surgery, however, all patients had diminished or absent responses with medial acceleration of the remaining utricle. Asymmetries averaged 65% after correction for spontaneous nystagmus. Our findings indicate that afferents for the L-VOR originate from the lateral region of the macula where hair cells with ipsilateral on-directions are located.
authors.affiliation: MRC Human Movement and Balance Unit, National Hospital for Neurology and Neurosurgery, London, UK.
authors.forename: T
authors.initials: T
authors.lastname: Lempert
authors.forename: C
authors.initials: C
authors.lastname: Gianna
authors.forename: G
authors.initials: G
authors.lastname: Brookes
authors.forename: A M
authors.initials: AM
authors.lastname: Bronstein
authors.forename: M A
authors.initials: MA
authors.lastname: Gresty
mesh_terms: D005123:Eye / Q000503:physiopathology*; D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D008575:Meniere Disease / Q000503:physiopathology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*