Cardiac Valve Surgery Can Result in Saccadic Palsy
Small study suggests that the cause may be a brainstem circuit malfunction
THURSDAY, Aug. 23 (HealthDay News) -- In patients who develop saccadic palsy after cardiac surgery, the selective loss of all types of saccades but not other eye movements suggests that the brainstem circuit that generates saccades may be malfunctioning, according to study findings published online Aug. 14 in the Annals of Neurology.
R. John Leigh, M.D., of Case Western Reserve University in Cleveland, and colleagues used the magnetic search coil technique to measure eye, eyelid and head movements in 10 patients.
The researchers found that the syndrome most often developed after aortic valve replacement and resulted in varying degrees of slowing and hypometria of saccades in either the vertical plane or in both the vertical and horizontal planes. Although the syndrome also affected quick phases of nystagmus, it did not appear to affect smooth pursuit, vergence and the vestibuloocular reflex. The investigators also found that the syndrome caused disability by limiting the patients' ability to shift their gaze and was often accompanied by dysarthria, labile emotions and unsteady gait.
"A current model of brainstem circuits could account for both hypometria and slowing," the authors conclude. "This syndrome and the visual disability it causes often go unrecognized unless saccades are systematically tested at the bedside."