Vertical saccades in superior oblique palsy and Brown's syndrome.
OBJECTIVE
To compare saccadic dynamics in superior oblique palsy and Brown's syndrome.


METHODS
Vertical saccades in adduction and in abduction were studied in two subjects with superior oblique palsy and one with Brown's syndrome. Using large numbers of centrifugal saccades over a wide range of amplitudes, we measured peak velocity, duration, and the peak velocity/mean velocity ratio (PV/MV) as a function of saccadic amplitude. We compared vertical saccades in 30 degrees of abduction with those in 30 degrees of adduction.


RESULTS
Superior oblique palsy caused a 15-18% reduction in peak velocities in adduction compared with abduction. Saccadic duration was also increased in adduction, with the result that there was no net change in the PV/MV ratio. In the patient with Brown's syndrome, velocities and durations of upward saccades were similar in abduction and adduction, but the PV/MV ratio was significantly elevated in adduction. We also observed an unusual high-speed lateral 'snap' of about 5 degrees that frequently interrupted vertical saccades in the midline but not elsewhere.


CONCLUSIONS
Both paresis and restriction of the superior oblique alter vertical saccades. The effects of restriction on saccadic dynamics are distinct from the effects of paresis.
Barton
J J
JJ
Human Vision and Eye Movement Laboratory, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. jbarton@caregroup.harvard.edu
Intriligator
J M
JM
D000328:Adult; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000503:physiopathology; D009801:Oculomotor Muscles / Q000503:physiopathology*; D009886:Ophthalmoplegia / Q000503:physiopathology*; D012438:Saccades / Q000502:physiology*; D013577:Syndrome