Research in Vestibular Science

Case Reports

Gaze-holding nystagmus in chronic progressive external ophthalmoplegia: a case report: Eugene Jung, Seo-Young Choi, Jae Hwan Choi, Kwang-Dong Choi; Res Vestib Sci. 2025;24(1):50-53. Published online March 14, 2025; DOI: https://doi.org/10.21790/rvs.2025.005

Abstract PDF Supplementary Material: We report a patient with chronic progressive external ophthalmoplegia (CPEO) who developed bilateral horizontal gaze-holding nystagmus, a previously unreported phenomenon. Video-oculography showed marked slowing of horizontal and vertical saccades, and bilateral horizontal gaze-evoked nystagmus with decreasing-velocity slow-phases waveforms. Horizontal rebound nystagmus was also observed. No abnormalities were identified in the brainstem or cerebellum on brain magnetic resonance imaging. A genetic analysis demonstrated a heterozygous missense mutation c.311A>G (p. D104G, rs28999114) in the SLC25A4 gene. Twitch motoneurons of the global layer receive inputs from premotor areas involved in the generation of eye movement, such as saccadic burst neurons, while non-twitch motoneurons of the orbital layer receive inputs from the medullary structures concerned with gaze-holding. In our patient with CPEO, the presence of omnidirectional ophthalmoplegia and bilateral horizontal gaze-holding nystagmus may indicate the involvement of the global layers of all extraocular muscles, as well as the orbital layers of the horizontal extraocular muscles.

Horizontal nystagmus with velocity-increasing waveforms in delayed post-hypoxic leukoencephalopathy: a case report: Eugene Jung, Suk-Min Lee, Seo-Young Choi, Kwang-Dong Choi; Res Vestib Sci. 2024;23(3):111-113. Published online September 15, 2024; DOI: https://doi.org/10.21790/rvs.2024.016

Abstract PDF Supplementary Material: Abnormal eye movements in unconscious patients serve as crucial diagnostic instruments, offering insights into the function of the central nervous system. Understanding these movements can aid in diagnosing the cause of unconsciousness, localizing brain lesions, and predicting outcomes. We report a patient who presented with spontaneous horizontal nystagmus unaffected by light in delayed post-hypoxic encephalopathy. Video-oculography showed exponentially increasing slow phases, with an amplitude ranging from 3° to 9° and a frequency of 0.5 Hz. Based on the results of oculography and neuroimaging, persistent horizontal nystagmus in our patient may be ascribed to an unstable neural integrator, possibly caused by disrupted cerebellar feedback mechanisms for horizontal gaze holding.

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