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Ooka T, Honda K, Tsutsumi T. Static cervico-ocular reflex in healthy humans. Acta Otolaryngol 2023; 143:387-391. [PMID: 37083024 DOI: 10.1080/00016489.2023.2201275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
BACKGROUND Dynamic cervico- (COR) and vestibulo-ocular reflex (VOR) contribute to stabilise visual images in the retina. The gain in dynamic COR is small in healthy individuals but increases in patients with vestibular dysfunction. Conversely, static COR has not been directly observed in healthy individuals. OBJECTIVES To elucidate the presence of static COR and quantify it in normal individuals in the roll plane. METHODS Eleven healthy participants were included in the study. Eye torsions were measured using video oculography to evaluate the static COR induced by lateral neck flexion during a head-upright-with-body-tilt position at 15°, 30°, and 45°. The ocular counterroll (OCR) was compared during whole-body and head tilts to assess the influence of static COR on OCR. RESULTS Static COR was significantly observed as eye torsion in the direction opposite to the body tilt. The head tilt OCR was significantly smaller than the whole-body tilt OCR to the right side but not to the left side. CONCLUSION Static COR exists in healthy individuals and tends to show higher amplitude as neck flexion stimulation increases.
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Affiliation(s)
- Tomoki Ooka
- Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiji Honda
- Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takeshi Tsutsumi
- Department of Otolaryngology, Tokyo Medical and Dental University, Tokyo, Japan
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Harada S, Imai T, Takimoto Y, Ohta Y, Sato T, Kamakura T, Takeda N, Kitahara T, Kondo M, Ueno Y, Shimada S, Inohara H. Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex. Sci Rep 2021; 11:17191. [PMID: 34433883 PMCID: PMC8387381 DOI: 10.1038/s41598-021-96596-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022] Open
Abstract
In the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement.
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Affiliation(s)
- Shotaro Harada
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takao Imai
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Yasumitsu Takimoto
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yumi Ohta
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takashi Sato
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Takefumi Kamakura
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Noriaki Takeda
- Department of Otorhinolaryngology - Head and Neck Surgery, Tokushima University Graduate School of Medicine, Tokushima, Japan
| | - Tadashi Kitahara
- Department of Otorhinolaryngology - Head and Neck Surgery, Nara Medical University, Nara, Japan
| | - Makoto Kondo
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yuya Ueno
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology - Head and Neck Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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