Patterns of spontaneous and head-shaking nystagmus in cerebellar infarction: imaging correlations.
Horizontal head-shaking may induce nystagmus in peripheral as well as central vestibular lesions. While the patterns and mechanism of head-shaking nystagmus are well established in peripheral vestibulopathy, they require further exploration in central vestibular disorders. To define the characteristics and mechanism of head-shaking nystagmus in central vestibulopathies, we investigated spontaneous nystagmus and head-shaking nystagmus in 72 patients with isolated cerebellar infarction. Spontaneous nystagmus was observed in 28 (39%) patients, and was mostly ipsilesional when observed in unilateral infarction (15/18, 83%). Head-shaking nystagmus developed in 37 (51%) patients, and the horizontal component of head-shaking nystagmus was uniformly ipsilesional when induced in patients with unilateral infarction. Perverted head-shaking nystagmus occurred in 23 (23/37, 62%) patients and was mostly downbeat (22/23, 96%). Lesion subtraction analyses revealed that damage to the uvula, nodulus and inferior tonsil was mostly responsible for generation of head-shaking nystagmus in patients with unilateral posterior inferior cerebellar artery infarction. Ipsilesional head-shaking nystagmus in patients with unilateral cerebellar infarction may be explained by unilateral disruption of uvulonodular inhibition over the velocity storage. Perverted (downbeat) head-shaking nystagmus may be ascribed to impaired control over the spatial orientation of the angular vestibulo-ocular reflex due to uvulonodular lesions or a build-up of vertical vestibular asymmetry favouring upward bias due to lesions involving the inferior tonsil.
Department of Neurology, College of Medicine, Seoul National University, Seoul National University Bundang Hospital 300 Gumi-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, 463-707, Korea.
Young Eun
YE
Huh
Ji Soo
JS
Kim
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests; D002531:Cerebellum / Q000098:blood supply* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006801:Humans; D007238:Infarction / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000473:pathology* / Q000503:physiopathology; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*