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Primary position upbeat nystagmus due to unilateral medial medullary infarction
Author(s) -
Hirose Genjiro,
Ogasawara Tomoko,
Shirakawa Tomoyasu,
Kawada Jyunya,
Kataoka Satoshi,
Yoshioka Akira,
Halmagyi G. Michael
Publication year - 1998
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410430323
Subject(s) - medullary cavity , lesion , nystagmus , medicine , vestibular system , anatomy , magnetic resonance imaging , vestibular nuclei , infarction , neuroscience , audiology , radiology , pathology , psychology , cardiology , myocardial infarction
Abstract We report on a patient who developed primary position upbeat nystagmus (ppUBN) due to a unilateral medial medullary infarction. On oculography, the slow phases of the nystagmus sometimes had an exponentially decreasing velocity waveform, indicating that the nystagmus was due to impairment of the vertical position‐to‐velocity neural integrator. On magnetic resonance imaging, the lesion was caudal to the vestibular nuclei and to the most rostral of the perihypoglossal nuclei, the nucleus intercalatus, a structure that was also involved in a previously reported case of ppUBN due to a unilateral medullary lesion. On the basis of these imaging and oculographic observations, we propose that a unilateral lesion of the nucleus intercalatus is sufficient to cause ppUBN and that the nucleus intercalatus is a part of the vertical position‐to‐velocity neural integrator in the human ocular–motor system.