Research in Vestibular Science

Hyun-June Shin

4 Articles

Two Cases of Myasthenia Gravis Showing Fatigibility Presenting with Decreased Gain of Smooth Pursuit: Ju-Hee Chae, Hyun-June Shin, Byoung-Soo Shin, Man-Wook Seo, Sun-Young Oh; Res Vestib Sci. 2019;18(2):54-58. Published online June 15, 2019; DOI: https://doi.org/10.21790/rvs.2019.18.2.54

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Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies to the acetylcholine receptors of the neuromuscular junction characterized by weakness and abnormal fatigability of the muscles. Therefore, the diagnosis of MG depends on the recognition of this distinctive pattern of fatigable weakness. Previous studies presented the diagnostic efficacy of saccadic eye movements in patients with ocular MG. We here in report 2 patients of ocular MG showing the fatigue effects during repetitive sustained smooth pursuit, and the effects of the administration of edrophonium on myasthenic smooth pursuit. Changes in smooth pursuits reflecting peripheral and secondary central mechanisms were demonstrated.

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Tracking Eye Movements for Diagnosis in Myasthenia Gravis: A Comprehensive Review
Minh N. L. Nguyen, Anneke van der Walt, Joanne Fielding, Meaghan Clough, Owen B. White
Journal of Neuro-Ophthalmology.2022; 42(4): 428. CrossRef

Visuospatial Dysfunction in Patients With the Right Vestibular Neuritis: Seung-Ho Jeon, Ko-Woon Kim, Hyun-June Shin, Byoung-Soo Shin, Man-Wook Seo, Sun-Young Oh; Res Vestib Sci. 2019;18(1):19-23. Published online March 15, 2019; DOI: https://doi.org/10.21790/rvs.2019.18.1.19

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Abstract PDF

Acute vestibular neuritis (VN) is characterized by acute/subacute vertigo with spontaneous nystagmus and unilateral loss of semicircular canal function. Vestibular system in human is represented in the brain bilaterally with functional asymmetries of the right hemispheric dominance in the right handers. Spatial working memory entails the ability to keep spatial information active in working memory over a short period of time which is also known as the right hemispheric dominance. Three patients (patient 1, 32-year-old female; patient 2, 18-year-old male; patient 3, 63-year-old male) suffered from acute onset of severe vertigo, nausea and vomiting. Patients 1 and 2’s examination revealed VN on the right side showing spontaneous left beating nystagmus and impaired vestibular ocular reflex on the right side in video head-impulse and caloric tests. Patient 3’s finding was fit for VN on the left side. We also evaluated visuospatial memory function with the block design test in these 3 VN patients which discovered lower scores in patients 1 and 2 and the average level in patient 3 compare to those of healthy controls. Follow-up block design test after resolved symptoms showed within normal range in both patients. Our cases suggest that the patients with unilateral peripheral vestibulopathy may have an asymmetrical effect on the higher vestibular cognitive function. The right VN can be associated with transient visuospatial memory dysfunction. These findings add the evidence of significant right hemispheric dominance for vestibular and visuospatial structures in the right-handed subjects, and of predominant dysfunction in the hemisphere ipsilateral to the peripheral lesion side.

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The Differential Effects of Acute Right- vs. Left-Sided Vestibular Deafferentation on Spatial Cognition in Unilateral Labyrinthectomized Mice
Thanh Tin Nguyen, Gi-Sung Nam, Jin-Ju Kang, Gyu Cheol Han, Ji-Soo Kim, Marianne Dieterich, Sun-Young Oh
Frontiers in Neurology.2021;[Epub] CrossRef

원활추종운동 이득감소로 근피로도를 확인한 중증근무력증 2예: Ju-Hee Chae, Hyun-June Shin, Byoung-Soo Shin, Man-Wook Seo, Sun-Young Oh; Received April 9, 2019 Accepted June 3, 2019 Published online June 3, 2019; [Accepted]

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Abstract: Myasthenia Gravis (MG) is an autoimmune disease caused by autoantibodies to the acetylcholine receptors of the neuromuscular junction characterized by weakness and abnormal fatigability of the muscles. Therefore, the diagnosis of MG depends on the recognition of this distinctive pattern of fatigable weakness. Previous studies presented the diagnostic efficacy of saccadic eye movements in patients with ocular MG. We here in report two patients of ocular MG showing the fatigue effects during repetitive sustained smooth pursuit, and the effects of the administration of edrophonium on myasthenic smooth pursuit. Changes in smooth pursuits reflecting peripheral and secondary central mechanisms were demonstrated.

Visuospatial dysfunction in patients with the right vestibular neuronitis: Seung-Ho Jeon, Sun-Young Oh, Ko-Woon Kim, Hyun-June Shin, Byoung-soo Shin, Man-Wook Seo; Received August 3, 2018 Accepted October 1, 2018 Published online October 1, 2018; [Accepted]

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Abstract: Acute vestibular neuritis is characterized by acute/subacute vertigo with spontaneous nystagmus and unilateral loss of semicircular canal function. Vestibular system in human is represented in the brain bilaterally with functional asymmetries of the right hemispheric dominance in the right handers. Spatial working memory entails the ability to keep spatial information active in working memory over a short period of time which is also known as the right hemispheric dominance. Three patients (Pt 1, 32-year-old female; Pt 2, 18-year-old male; Pt 3, 63-year-old male) suffered from acute onset of vertigo. Pt 1 and 2’s examination revealed vestibular neuritis (VN) on the right side showing spontaneous left beating nystagmus and impaired vestibular ocular reflex (VOR) on the right side in video head-impulse and caloric tests. Pt 3’s finding was fit for VN on the left side. We also evaluated visuospatial memory function with the block design test in these three VN patients which discovered lower scores in Pt 1 and 2 and the average level in Pt 3 compare to those of healthy controls. Follow up block design test after resolved symptoms showed within normal range in both patients. Our cases suggest that the patients with unilateral peripheral vestibulopathy may have an asymmetrical effect on the higher vestibular cognitive function. The right VN can be associated with transient visuospatial memory dysfunction. These findings add the evidence of significant right hemispheric dominance for vestibular and visuospatial structures in the right-handed subjects, and of predominant dysfunction in the hemisphere ipsilateral to the peripheral lesion side.

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