Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain un...Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain unclear, the most widely accepted explanation is the sensory conflict theory,which identifies two main sources of conflict: discrepancies between visual and vestibular inputs and conflicts within the vestibular system itself.This study aims to evaluate otolith-mediated verticality perception in first-time seafarers on board a naval frigate ship using the Subjective Visual Vertical(SVV) test.Methods:This observational study was conducted on board a naval frigate and involved two groups. The case group consisted of50 newly recruited sailors experiencing their first sea voyage. The SVV test was conducted at three time points: prior to embarkation, during an active episode of sea sickness, and after disembarkation. A control group of 50 healthy, experienced sailors-regular seafarers with no history of vestibular symptoms underwent the same SVV testing at corresponding intervals. The results from both groups were collected and analyzed to assess changes in verticality perception related to sea exposure and sea sickness.Results:Analysis of the SVV test data from the 50 newly recruited sailors(case group) demonstrated a statistically significant difference compared to the control group of experienced sailors. During an active episode of sea sickness, the case group exhibited a notable tilt and deviation in SVV angles, indicating altered verticality perception. These deviations reduced significantly 24 hours post-disembarkation, suggesting an improvement in verticality perception once the motion stimulus was removed.Conclusion:This distinctive study assessed otolith-mediated verticality perception using the SVV test in first-time seafarers experiencing sea sickness aboard a naval frigate. Our findings emphasize the functional importance of the otolith organs in maintaining spatial orientation during maritime motion exposure. The observed SVV deviations support the subjective vertical conflict theory, highlighting the role of vestibular-visual mismatch in the development of sea sickness. However, our findings more likely reflect transient functional disturbance or overstimulation rather than a pre-existing utricular asymmetry alone. Based on the pattern of SVV deviation and recovery, we propose that the utricle may play a more significant role than the saccule in inducing sea sickness.展开更多
Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for ...Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for the Indian population.Methods:SVV was examined in 30 patients with PC-BPPV before and after canalith repositioning maneuver and after complete resolution of PC-BPPV.Study parameters included the mean of 10 angular tilt readings and direction of deviation,which were compared before and after CRM and following complete resolution of PC-BPPV.Results:The angle of SVV tilt was greater and deviated towards the affected ear before CRM in all patients,which decreased significantly shortly after CRM and continued to decrease after complete resolution of PC-BPPV(p<0.0001).Conclusions:SVV can be used to test utricular dysfunction in PC-BPPV.The angle of tilt improves in response to CRM,which may be used as a prognostic marker in patients with PC-BPPV receiving CRM.展开更多
Objective To study the value of the subjective visual vertical(SVV)in the diagnosis of vestibular migraine(VM).Methods This study recruited 128 VM patients and 64 age-matched normal subjects.We detected the SVV during...Objective To study the value of the subjective visual vertical(SVV)in the diagnosis of vestibular migraine(VM).Methods This study recruited 128 VM patients and 64 age-matched normal subjects.We detected the SVV during the interval between attacks in both groups,in sitting upright,and the head tilted at 45°to the left or right.We then examined the correlation between the SVV results with the vestibular evoked myogenic potential(VEMP)and canal paresis(CP).Results It was found there was a significant difference in SVV at the upright position between VM patients and normal controls(P=0.006)and no significant difference was found at the tilts of 45°to the left or right between the two groups.The SVV results at the upright position were significantly correlated with cervical VEMP(P=0.042)whereas not significantly correlated with CP and VEMP.There existed no significant difference in the conformity to the Müller effect(M effect)between the two groups.ROC analysis exhibited that the sensitivity,specificity of SVVs at the upright were 67.200%and 62.500%respectively.The diagnostic value of SVV at the upright position was significantly higher than that at tilts of 45°to the left and right(P=0.006).Nonetheless the diagnostic accuracy was relatively low.Conclusion Abnormality in SVV possibly stems from the lasting functional disorder of cerebellar or high-level cortical centers in VM patients or is linked to the vestibular compensation.The SVV is of low diagnostic value for VM and the value of SVV in VM warrants further study.展开更多
Subjective visual vertical(SVV)and subjective visual horizontal(SVH)tests can be used to evaluate the perception of verticality and horizontality,respectively,and can aid the diagnosis of otolith dysfunction in clinic...Subjective visual vertical(SVV)and subjective visual horizontal(SVH)tests can be used to evaluate the perception of verticality and horizontality,respectively,and can aid the diagnosis of otolith dysfunction in clinical practice.In this study,SVV and SVH screen version tests are implemented using virtual reality(VR)equipment;the proposed test method promotes a more immersive feeling for the subject while using a simple equipment configuration and possessing excellent mobility.To verify the performance of the proposed VR-based SVV and SVH tests,a reliable comparison was made between the traditional screen-based SVV and SVH tests and the proposed method,based on 30 healthy subjects.The average results of our experimental tests on the VR-based binocular SVV and SVH equipment were−0.15◦±1.74 and 0.60◦±1.18,respectively.The proposed VR-based method satisfies the normal tolerance for horizontal or vertical lines,i.e.,a±3◦error,as defined in previous studies,and it can be used to replace existing test methods.展开更多
文摘Objectives:Sea sickness, a form of motion sickness, is a common condition among sailors on various sailing vessels, primarily due to their roll and pitch movements. While the exact neurobiological mechanisms remain unclear, the most widely accepted explanation is the sensory conflict theory,which identifies two main sources of conflict: discrepancies between visual and vestibular inputs and conflicts within the vestibular system itself.This study aims to evaluate otolith-mediated verticality perception in first-time seafarers on board a naval frigate ship using the Subjective Visual Vertical(SVV) test.Methods:This observational study was conducted on board a naval frigate and involved two groups. The case group consisted of50 newly recruited sailors experiencing their first sea voyage. The SVV test was conducted at three time points: prior to embarkation, during an active episode of sea sickness, and after disembarkation. A control group of 50 healthy, experienced sailors-regular seafarers with no history of vestibular symptoms underwent the same SVV testing at corresponding intervals. The results from both groups were collected and analyzed to assess changes in verticality perception related to sea exposure and sea sickness.Results:Analysis of the SVV test data from the 50 newly recruited sailors(case group) demonstrated a statistically significant difference compared to the control group of experienced sailors. During an active episode of sea sickness, the case group exhibited a notable tilt and deviation in SVV angles, indicating altered verticality perception. These deviations reduced significantly 24 hours post-disembarkation, suggesting an improvement in verticality perception once the motion stimulus was removed.Conclusion:This distinctive study assessed otolith-mediated verticality perception using the SVV test in first-time seafarers experiencing sea sickness aboard a naval frigate. Our findings emphasize the functional importance of the otolith organs in maintaining spatial orientation during maritime motion exposure. The observed SVV deviations support the subjective vertical conflict theory, highlighting the role of vestibular-visual mismatch in the development of sea sickness. However, our findings more likely reflect transient functional disturbance or overstimulation rather than a pre-existing utricular asymmetry alone. Based on the pattern of SVV deviation and recovery, we propose that the utricle may play a more significant role than the saccule in inducing sea sickness.
文摘Objective:To study the potential role of subjective visual vertical(SVV)as a prognostic marker for canalith repositioning maneuver(CRM)in patients with posterior canal benign paroxysmal positional vertigo(PC-BPPV)for the Indian population.Methods:SVV was examined in 30 patients with PC-BPPV before and after canalith repositioning maneuver and after complete resolution of PC-BPPV.Study parameters included the mean of 10 angular tilt readings and direction of deviation,which were compared before and after CRM and following complete resolution of PC-BPPV.Results:The angle of SVV tilt was greater and deviated towards the affected ear before CRM in all patients,which decreased significantly shortly after CRM and continued to decrease after complete resolution of PC-BPPV(p<0.0001).Conclusions:SVV can be used to test utricular dysfunction in PC-BPPV.The angle of tilt improves in response to CRM,which may be used as a prognostic marker in patients with PC-BPPV receiving CRM.
基金funded by grants from the Shanghai Science and Technology Commission(No.18ZR1439200)the National Natural Science Foundation of China(No.81873701)+1 种基金the Innovation Items in the Military Service Field of Changzheng Hospital(No.2019CZJS102,No.2020CZWJFW10)the National Twelfth Five-Year Research Program of China(No.2012BAI12B02).
文摘Objective To study the value of the subjective visual vertical(SVV)in the diagnosis of vestibular migraine(VM).Methods This study recruited 128 VM patients and 64 age-matched normal subjects.We detected the SVV during the interval between attacks in both groups,in sitting upright,and the head tilted at 45°to the left or right.We then examined the correlation between the SVV results with the vestibular evoked myogenic potential(VEMP)and canal paresis(CP).Results It was found there was a significant difference in SVV at the upright position between VM patients and normal controls(P=0.006)and no significant difference was found at the tilts of 45°to the left or right between the two groups.The SVV results at the upright position were significantly correlated with cervical VEMP(P=0.042)whereas not significantly correlated with CP and VEMP.There existed no significant difference in the conformity to the Müller effect(M effect)between the two groups.ROC analysis exhibited that the sensitivity,specificity of SVVs at the upright were 67.200%and 62.500%respectively.The diagnostic value of SVV at the upright position was significantly higher than that at tilts of 45°to the left and right(P=0.006).Nonetheless the diagnostic accuracy was relatively low.Conclusion Abnormality in SVV possibly stems from the lasting functional disorder of cerebellar or high-level cortical centers in VM patients or is linked to the vestibular compensation.The SVV is of low diagnostic value for VM and the value of SVV in VM warrants further study.
基金supported by the Soonchunhyang University Research Fund and 2018 Ulsan University Hospital Research Grant(UUH-2018-12)(Grantee:JYP,http://www.uuh.ulsan.kr).The authors are grateful for their supports.
文摘Subjective visual vertical(SVV)and subjective visual horizontal(SVH)tests can be used to evaluate the perception of verticality and horizontality,respectively,and can aid the diagnosis of otolith dysfunction in clinical practice.In this study,SVV and SVH screen version tests are implemented using virtual reality(VR)equipment;the proposed test method promotes a more immersive feeling for the subject while using a simple equipment configuration and possessing excellent mobility.To verify the performance of the proposed VR-based SVV and SVH tests,a reliable comparison was made between the traditional screen-based SVV and SVH tests and the proposed method,based on 30 healthy subjects.The average results of our experimental tests on the VR-based binocular SVV and SVH equipment were−0.15◦±1.74 and 0.60◦±1.18,respectively.The proposed VR-based method satisfies the normal tolerance for horizontal or vertical lines,i.e.,a±3◦error,as defined in previous studies,and it can be used to replace existing test methods.
