Saccadic palsy after cardiac surgery: characteristics and pathogenesis.
OBJECTIVE
To characterize the syndrome of saccadic palsy that may follow cardiac surgery, and to interpret the findings using current concepts of the neurobiology of fast eye movements.


METHODS
Using the magnetic search coil technique, we measured eye, eyelid, and head movements of 10 patients who developed selective palsy of saccades after cardiac surgery.


RESULTS
Patients showed varying degrees of slowing and hypometria of saccades in the vertical plane or both horizontal and vertical planes, with complete loss of all saccades in one patient. Quick phases of nystagmus were also affected, but smooth pursuit, vergence, and the vestibuloocular reflex were usually spared. The smallest saccades were less slowed than larger saccades. Affected patients were visually disabled by loss of ability to voluntarily shift their direction of gaze. Blinks and head thrusts modestly improved the range and speed of voluntary movement. The syndrome usually followed aortic valve replacement. Common accompanying features included dysarthria, labile emotions, and unsteady gait. The saccadic palsy either improved during the early part of the course or remained static.


CONCLUSIONS
Selective loss of all forms of saccades, with sparing of other eye movements, indicates malfunction of the brainstem machinery that generates saccades. A current model of brainstem circuits could account for both hypometria and slowing. This syndrome and the visual disability it causes often go unrecognized unless saccades are systematically tested at the bedside.
Solomon
David
D
Departments of Neurology and Otolaryngology, Johns Hopkins University, Baltimore, MD, USA.
Ramat
Stefano
S
Tomsak
Robert L
RL
Reich
Stephen G
SG
Shin
Robert K
RK
Zee
David S
DS
Leigh
R John
RJ
D000328:Adult; D000368:Aged; D013504:Cardiovascular Surgical Procedures / Q000009:adverse effects*; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009759:Nystagmus, Pathologic / Q000209:etiology / Q000503:physiopathology*; D015840:Oculomotor Nerve Diseases / Q000209:etiology / Q000503:physiopathology*; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology*; D012438:Saccades / Q000502:physiology*