Development of a Clinical Examination to Evaluate Gravity Perception during Static Head Roll Tilt

Kurita

et al. 2017

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ObjectivesTilt perception is part of the perception of spatial orientation. It is determined not only by the allocentric gravity axis, but also by a second allocentric axis induced by visual information as well as by the egocentric body (head) axis induced by somatosensory information. The aim of this study was to quantify roll‐tilt perception using the subjective visual vertical (SVV) and the newly developed subjective postural head vertical (SPHV) and to investigate the visual effects on both during static roll‐tilt.Study DesignBasic scienceMethodsNine male volunteers participated in this study. A flight simulator was used to create several roll‐tilt environments that were then combined with visual information. SVV and SPHV were evaluated in healthy participants during static roll‐tilt.ResultsThe SVV evaluation revealed significant differences between the dark condition (control) and other visual conditions with respect to some of the body roll‐tilt environments, and between a body roll‐tilt of 0° and ≥ 20°. The SPHV evaluation revealed a significant difference between the dark condition and the visual condition that was always roll‐tilted 20° to the right of the body axis. However, there were no significant differences in SPHV error between a body roll‐tilt of 0° and other tilt angles for every visual condition, unlike SVV error.ConclusionsOur data indicate that human susceptibility to spatial disorientation is dependent on roll‐tilt angle and visual information. They also suggest that the SPHV is not affected by roll‐tilt angle, and thus differs from SVV.Level of EvidenceNA

Section: Discussionmentioning

confidence: 99%

Section: Evaluation Of the Sphvmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Visual effects on the subjective visual vertical and subjective postural head vertical during static roll‐tilt

Tamura

Kurita

et al. 2017

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“…Sixty‐six healthy men, aged 20‐38 (mean 21.8) years, participated in the experiment. To ensure clinical relevance, we previously developed a simple, compact examination system (Figure 1C; head‐tilt subjective visual vertical [HT‐SVV] examination system, UNIMEC, Tokyo, Japan) to simultaneously measure the SVV and head roll‐tilt angle (HTA), with no flight simulator needed, and then analyze the data 23 . During the experiment, the participant sat on a chair approximately 60 cm from a bar‐display box and wore goggles, to exclude visual information except for that of a bar (7 cm long × 0.2 cm wide) on the display.…”

Section: Methodsmentioning

confidence: 99%

Effect of head roll‐tilt on the subjective visual vertical in healthy participants: Towards better clinical measurement of gravity perception

Yamanaka

Kitahara

et al. 2020

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Objective: Gravity perception is an essential function for spatial orientation and postural stability; however, its assessment is not easy. We evaluated the head-tilt perception gain (HTPG, that is, mean perceptual gain [perceived/actual tilt angle] during left or right head roll-tilt conditions) and head-upright subjective visual vertical (SVV) using a simple method developed by us to investigate the characteristics of gravity perception in healthy participants. Methods: We measured the SVV and head roll-tilt angle during head roll-tilt within ±30 of vertical in the sitting and standing positions while the participant maintained an upright trunk (sitting, 434 participants; standing, 263 participants). We evaluated the head-upright SVV, HTPG, and laterality of the HTPG. Results: We determined the reference ranges of the absolute head-upright SVV (<2.5), HTPG (0.80-1.25), and HTPG laterality (<10%) for the sitting position. The head-upright SVV and HTPG laterality were not influenced by sex or age. However, the HTPG was significantly greater in women than in men and in middle-aged (30-64 years) and elderly (65-88 years) participants than in young participants (18-29 years). The HTPG, but not the head-upright SVV or HTPG laterality, was significantly higher in the standing vs sitting position. Conclusion: The HTPG is a novel parameter of gravity perception involving functions of the peripheral otolith and neck somatosensory systems to the central nervous system. The HTPG in healthy participants is influenced by age and sex in the sitting position and immediately increases after standing to reinforce the righting reflex for unstable posture, which was not seen in the head-upright SVV, previously considered the only parameter.

“…To examine GPD in more detail, we established the head‐tilt SVV test (HT‐SVV test), which is performed with the head upright and statically tilted to the left and right. 14 We have previously reported the results of the HT‐SVV test in healthy participants 1 and patients with vertigo/dizziness. 15 , 16 The HT‐SVV test assesses the left and right head‐tilt perception gains (HTPGs), which is a parameter used to evaluate the magnitude of gravity perception with the head statically tilted to the left and right, in addition to the HU‐SVV.…”

Section: Introductionmentioning

confidence: 99%

Gravity perception disturbance in patients with unilateral Meniere disease

Shiozaki

Yamanaka

et al. 2023

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Objective: To investigate gravity perception disturbance (GPD) in patients with Meniere disease (MD), we classified GPD type based on the results of the head-tilt perception gain (HTPG) and the head-upright subjective visual vertical (HU-SVV) evaluated by the head-tilt SVV (HT-SVV) test in patients with unilateral MD. Methods:We conducted the HT-SVV test on 115 patients with unilateral MD and 115 healthy controls. Among the 115 patients, the period from the first vertigo episode to the examination (PFVE) was known for 91 patients. Results:The HT-SVV test classified 60.9% and 39.1% of patients with unilateral MD as GPD and non-GPD, respectively. GPD was classified according to HTPG/HU-SVV combinations as follows: Type A GPD (21.7%, normal HTPG/abnormal HU-SVV), Type B GPD (23.5%, abnormal HTPG/normal HU-SVV), and Type C GPD (15.7%, abnormal HTPG/abnormal HU-SVV). As the PFVE became longer, patients with non-GPD and Type A GPD decreased; however, those with Types B and C GPD increased. Conclusion:This study provides novel information on unilateral MD from the perspective of gravity perception by classifying GPD based on the results of the HT-SVV test. This study's findings suggest that overcompensation for vestibular dysfunction in patients with unilateral MD exhibited by large HTPG abnormalities may be strongly associated with persistent postural-perceptual dizziness.