Author Login

Correspondence to Author: Fumiyuki Goto M.D. Ph.D, 

Department of Otorhinolaryngology, Hino Municipal Hospital, Tamadaira 4-3-1, Hino-shi, Tokyo 191-0062, Japan,

Abstract:

Objective : The purpose of this study was to look into how healthy male subjects’ subjective visual verticals (SVV) changed after prolonged lateral body tilts in both light and dark environments. Aim : Both sitting and lying down positions allowed for the acquisition of static SVVs. The patient was advised to lie down and remain in that position for the subsequent series of recordings once the measurement was completed in the sitting position. SVV was assessed right away and eight more times at intervals of 15 minutes. Finally, the individual was placed back in the sitting posture, and the SVV was assessed both in light and darkness, right away and after 15 minutes.

Conclusion :The subjective awareness of the contralateral tilt of the real vertical is a phenomenon that may contribute to maintaining one’s head in the vertical position, according to a comparison of SVVs in dark and light conditions. We suggest that one of the key inputs to stabilise visual vertical is this visual effect. Therefore, sustaining one’s upright position on earth would require visual input.

Keywords : Vestibular; Subjective visual vertical; Otolith; Ocular counter-rolling

Introduction: The A-phenomena, also known as Aubert’s phenomenon, is the subjective experience of a contralateral tilt of the subjective vertical while one is supine [1]. The real vertical appears to shift towards the ipsilateral side when there is a minor body tilt, which is known as the E-phenomenon (Mueller phenomenon) [2]. Both phenomena have received in-depth research [3-5]. The SVV has not yet been studied in relation to variations in protracted lateral body tilt postures under various visual circumstances. Sometimes when we wake up after a night’s sleep, we feel unsteady. We propose that this unsteadiness is a result of temporal alterations in graviceptive function brought on by prolonged horizontal body positioning. As a start periods. We looked into the role of visual inputs in the temporal changes in SVV that occur when subjects shift from a sitting to a protracted laying position as a first step in testing this theory.

ConclusionsWe looked into how the subjects’ SVV changed over time while they were lying in a protracted lateral position. All subjects’ SVVs tipped in the same direction as their head tilts shortly after they lied down. This response, known as the A-phenomenon, grew steadily before plateauing. The amount of time needed to achieve the plateau was shortened by visual input. The SVVs recorded with and without visual input were the same until the plateau was attained. With time, the SVVs’ observed dispersion in the presence of visual input reduced,SVV dispersion, however, was unaffected by the absence of visual input. These findings suggest that the body is stabilised for SVV determination by visual input. The A-phenomenon uses visual information to strengthen graviceptive circuits. The head needs to remain erect, thus this is crucial.

References1. von Aubert H (1861) Eine scheinbare bedoutende Drehung von Objecten bei Neigung des Kopfes nach rechts oder links. Arch Pathol Anat 20: 381-393. 2. Mueller C, Kornilova L, Wiest G, Deecke L (1994) Visually induced vertical selfmotion Sensation is altered in microgravity. J Vestib Res 4: 161-167. 3. Van Beuzekom AD, Medendorp WP, Van Gisbergen JA (2001) The subjective vertical and the sense of self orientation during active body tilt. Vision Res 41: 3229- 3242.4. Van Beuzekom AD, Van Gisbergen JA (2000) Properties of the internal representation of gravity inferred from spatial-direction and body-tilt estimates. J Neurophysiol 84: 11-27. 5. Curthoys IS (1996) The role of ocular torsion in visual measures of vestibular function. Brain Res Bull 40: 399-403. 6. Goto F, Kobayashi H, Hayashi Y, Higashino K, Kunihiro T, et al. (2003) Compensatory changes in static and dynamic subjective visual vertical in patients following vestibular schwanoma surgery. Auris Nasus Larynx 30: 29-33. 7. Kobayashi H, Hayashi Y, Higashino K, Saito A, Kunihiro T, et al.(2002) Dynamic and static subjective visual vertical with aging. Auris Nasus Larynx 29: 325-328. 8. Vibert D, Hausler R (2003) Acute peripheral vestibular defi cits after whiplash injuries. Ann Otol Rhinol Laryngol 112: 246-51. 9. Brandt T (1999) Vestibular disordes in (frontal) roll plane. In: Brandt T, editor.Vertigo: Its multisensory syndromes. 2 ndedn London: Springer 10. Dieterich M, Brandt T (1993) Ocular torsion and tilt of subjective vetrtical are sensitive brainstem signs. Ann Neurol 33: 292-299. 11. MILLER EF 2nd (1962) Counterrolling of the human eyes produced by head tilt with respect to gravity. Acta OtoLaryngol 54: 479-501. 12. Groen E, Bos JE, Nacken PF, de Graaf B (1996) Determination of ocular torsion by means of automatic pattern recognition. IEEE Trans Biomed Eng 43: 471-479. 13. Kobayashi N, Yashiro T, Ishii M, Sekiguchi C (2001) Factors infl uencing ocular counterrolling. Oto-rhinolaryngology, Tokyo 44: 457-65. 14. Kobayashi N (1998) Relationship between changes in OCR and directional cognition inlong term tilt loading. Equilibrium Res 57: 522-528. 15. Nomura Y, Watanabe Y, Igarashi M, Sudoh M, Sekiguchi C, et al. (2000) Ocular counter-rolling after prolonged alteration in the direction of gravity. Nippon Jibiinkoka Gakkai Kaiho 103: 916-921. 16. Wade SW, Curthoys IS (1997) The effect of ocular torsional position on perception of the roll-tilt of visual stimuli. Vision Res 37: 1071-1078.

Citation:

Fumiyuki Goto M.D. Ph.D Visual Input During Prolonged Lateral Tilt Position: Contribution to the Subjective Visual Vertical. Clinics of Neurology 2024.