Video 4.13 Gaze-evoked nystagmus and saccadic vestibulo-ocular reflex suppression (VORS) in spinocerebellar ataxia type 6 from Neuro-Ophthalmology and Neuro-Otology Textbook
Creator
Daniel R. Gold, DO
Affiliation
(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: This is a 45-yo-man who was recently diagnosed with SCA 6. There was no clear spontaneous downbeat nystagmus (DBN) in primary gaze, although DBN could clearly be provoked by convergence. Other ocular motor features included choppy pursuit and VOR suppression horizontally and vertically, in addition to an alternating hypertropia (skew deviation), gaze-evoked and rebound nystagmus. Saccades were normal. His VOR was completely normal. These are all typical ocular motor features of a flocculus/paraflocculus syndrome. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: On exam, there was no clear spontaneous downbeat nystagmus (DBN) in primary gaze, although DBN could clearly be provoked by convergence. Other ocular motor features included saccadic pursuit and VORS (suggestive of a normal VOR - i.e., there was a VOR to suppress, but given the pursuit defcit, VORS was saccadic) horizontally and vertically, in addition to an alternating skew deviation (right hypertropia in right gaze and left hypertropia in left gaze), gaze-evoked and rebound nystagmus. Saccades were normal. Head impulse test was normal. These are all typical ocular motor features of a focculus/parafocculus syndrome. https:// collections.lib.utah.edu/ark:/87278/s6vx45m7
