title: Slowly alternating skew deviation: description of a pretectal syndrome in three patients.
abstract: Three patients who had slowly alternating skew deviation are described; each had elements of the Sylvian aqueduct syndrome. This combination of signs supports a pretectal location for lesions associated with alternating skew movements. Postmortem examination of a patient who died of chronic herpes simplex encephalitis showed extensive demyelination and periaqueductal spongiform degeneration; there was preservation of the oculomotor and trochlear nuclei, the medial longitudinal fasciculus, vestibular nuclei, and the interstitial nucleus of Cajal bilaterally. The slowly alternating dysconjugate vertical movements bear a resemblance to both see-saw nystagmus and the ocular tilt response.
mesh_terms: D001921:Brain / Q000473:pathology; D002535:Cerebral Aqueduct / Q000473:pathology*; D002544:Cerebral Infarction / Q000473:pathology*; D003711:Demyelinating Diseases / Q000473:pathology; D004660:Encephalitis / Q000473:pathology*; D005133:Eye Movements; D005260:Female; D006561:Herpes Simplex / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D009410:Nerve Degeneration; D009759:Nystagmus, Pathologic / Q000473:pathology; D012438:Saccades; D013477:Superior Colliculi / Q000473:pathology*