Spontaneous nystagmus in dorsolateral medullary infarction indicates vestibular semicircular canal imbalance.
BACKGROUND
Spontaneous nystagmus caused by dorsolateral medullary infarction may be of vestibular origin.


OBJECTIVE
To test if imbalance of the central pathways of the semicircular canals contributes to spontaneous nystagmus in dorsolateral medullary syndrome.


METHODS
We examined four patients with dorsolateral medullary syndrome and recorded spontaneous nystagmus binocularly at gaze straight ahead with the three-dimensional search coil technique. The median slow phase velocity of the nystagmus was analysed in the light and in the dark, and the normalised velocity axes were compared with the rotation axes as predicted from anatomical data of the semicircular canal.


RESULTS
The slow phase rotation axes of all patients aligned best with the rotation axes resulting from stimulation of the contralesional posterior and horizontal semicircular canals. This alignment cannot be explained by pure otolith imbalance.


CONCLUSIONS
We propose that vestibular imbalance caused by an ipsilesional lesion of the central semicircular canal pathways of the horizontal and anterior semicircular canals largely accounts for spontaneous nystagmus in dorsolateral medullary syndrome.
Rambold
H
H
Department of Neurology, University of Luebeck, Ratzeburger Allee 160, D-23538 Luebeck, Germany. rambold_h@neuro.mu-luebeck.de
Helmchen
C
C
D000368:Aged; D005260:Female; D006801:Humans; D014854:Lateral Medullary Syndrome / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000209:etiology* / Q000503:physiopathology; D012665:Semicircular Canals / Q000503:physiopathology*; D014722:Vestibule, Labyrinth / Q000503:physiopathology