Research in Vestibular Science

Case Reports

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

Isolated Infarction of Anterior Cerebellar Vermis: Sung-Hee Kim, Ji-Soo Kim; Res Vestib Sci. 2016;15(4):147-150. Published online December 12, 2016; DOI: https://doi.org/10.21790/rvs.2016.15.4.147

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Abstract PDF

The anterior cerebellar vermis has been known to act in coordination of gait and postural adjustment of the trunk and legs. However, oculomotor abnormalities in an isolated anterior vermian lesion have not been described in the literature. A 59-year-old man presented with acute non-rotatory dizziness and disequilibrium. Neuro-ophthalmologic examination found impaired smooth pursuit and hypometric saccades in the contralesional direction, and disconjugate ipsiversive ocular torsion, but without spontaneous or gaze-evoked nystagmus. Imaging study showed an infarction restricted to the rostral end of right cerebellar vermis involving the lingual and central lobules. The anterior cerebellar vermis participates in the maintenance of axial posture and gait, and also in the control of ocular motor and vestibular systems.

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Free water imaging unravels unique patterns of longitudinal structural brain changes in Parkinson’s disease subtypes
Abigail E. Bower, Sophia J. Crisomia, Jae Woo Chung, Justin P. Martello, Roxana G. Burciu
Frontiers in Neurology.2023;[Epub] CrossRef

Original Article

Initiation of Smooth Pursuit in Acute Cerebellar Infarction: A Preliminary Study: Tae Ho Yang, Sun Young Oh; Res Vestib Sci. 2013;12(2):47-53.

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Abstract: Background and Objectives: The cerebellar lesion causes an initiation deficit of smooth-pursuit eye movement depending on the location of the lesion. We investigated the initiation of smooth pursuit in patients with cerebellar infarction and in healthy subjects, using step-ramp stimuli. Materials and Methods: Ten patients with cerebellar infarction documented by brain magnetic resonance imaging and fifty healthy subjects are recruited. To estimate the initiation of smooth pursuit, the onset latency and initial acceleration during the first 100ms of the horizontal smooth pursuit were estimated using the step-ramp target stimuli (5°/sec, 10°/sec, and 20°/sec). Results: In healthy subjects, onset latency of pursuit was shortened and initial acceleration was increased as target velocity was increasing. In patients with unilateral cerebellar infarction, the onset latency of ipsilesional smooth pursuit was significantly delayed at the target velocities of 10°/sec and 20°/sec. For the fast target velocity of 20°/sec, there was significant decrease of the initial acceleration of contralesional pursuit. Conclusion: In comparison with the healthy subjects, the patients with unilateral cerebellar lesions showed significant delay of pursuit onset and decrease of initial eye acceleration in the fast target velocity. These results support that the cerebellar lesions affect not only steady-state smooth pursuit gain but also the processing time required to initiate smooth pursuit, i.e., onset latency and initial acceleration. More extensive study is needed to confirm the role of cerebellum for parametric adjustment of each component of smooth pursuit.

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