Dissociated palsy of vertical saccades: loss of voluntary and visually guided saccades with preservation of reflexive vestibular quick phases.
A patient with a diencephalic infarct displayed a persistent palsy of voluntary and visually guided vertical saccades with preserved vertical quick phases of vestibular nystagmus on magnetic search coil oculography. Vertical smooth pursuit had very low velocity in both directions without catch-up saccades. Vertical and torsional vestibulo-ocular reflex gains were normal. Preservation of vertical and torsional quick phases signifies integrity of the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF). This case is the first to provide evidence that disruption of descending cerebral corticofugal pathways to the riMLF with preserved ascending projections from the paramedian pontine reticular formation to the riMLF can cause a dissociated palsy of vertical fast eye movements.
Department of Neurology, Cheju National University College of Medicine, Cheju, Republic of Korea.
Ji-Hoon
JH
Kang
James A
JA
Sharpe
D001933:Brain Stem / Q000503:physiopathology; D020526:Brain Stem Infarctions / Q000473:pathology / Q000503:physiopathology; D002531:Cerebellum / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D015835:Ocular Motility Disorders / Q000209:etiology / Q000503:physiopathology*; D009801:Oculomotor Muscles / Q000294:innervation / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology*; D012021:Reflex, Abnormal / Q000502:physiology; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D013681:Tegmentum Mesencephali / Q000473:pathology / Q000503:physiopathology; D014726:Vestibular Nuclei / Q000502:physiology; D014722:Vestibule, Labyrinth / Q000502:physiology; D014836:Volition / Q000502:physiology*