Selective Saccadic Palsy

This case is published courtesy of Scott D.Z. Eggers, M.D., Department of Neurology, Mayo Clinic College of Medicine (1). The patient is a healthy 50 year old woman who underwent otherwise uncomplicated aortic valve replacement for an incidentally discovered ascending aortic aneurysm. Upon awakening from anesthesia she noted difficulties directing her gaze and began using head movements to facilitate gaze shifts. She had no dysarthria, dysphagia or gait instability. She was discharged and had no problems other than her visual complaints for three months at which time she developed complex partial seizures that responded to levetiracetam. On examination ten months post-operatively, a general neurological exam was notable only for diffuse hyporeflexia. Visual acuity, pupils, visual fields and fundoscopic examination were normal. Examination of the eye movements showed: 1.Straight ahead fixation was steady and no spontaneous saccades, square wave jerks or nystagmus was seen ophthalmoscopically. 2.She made no fast volutional or reflexive saccades in any direction, but instead made extremely slow eye movements to eventually reach a target, except for slightly faster downward saccades. 3.Pursuit was smooth and of full range horizontally and vertically, even with high frequencies. 4.With a horizontal optokinetic drum the eyes can fix laterally in the orbits without any corrective quick phases, but she made a few downbeats of nystagmus with upward optokinetic (OKN) drum. 5.Vestibular slow phases, with slow oculocephalics and with rapid head impulse testing were normal. 6.Torsional head rolling produced excellent counter-rolling, but without any torsional quick phases. 7.Fixation suppression of the vestibule-ocular reflex was intact. 8.With head-free gaze shifts, she made exaggerated head turns associated with blinks, with contraversive vestibular slow phase eye movements that place the eyes in the corner of the orbits until the head was maximally rotated, and then the eyes would continue to slowly drift toward the target as can be seen in congenital ocular motor apraxia. Eye movements were recorded with video oculography. Figure A shows video oculography recordings of the patient. Horizontal saccades were absent during random saccade paradigm (top) but sinusoidal smooth pursuit was normal across all frequencies (bottom). Vertical eye movements demonstrated the same findings. Additionally rotary chair sinusoidal vestibular and optokinetic testing demonstrated normal vestibular slow phases and optokinetic ocular following reflex, but absent vestibular or OKN quick phases of nystagmus (not shown). Investigations: Figure B MRI of the brain showing a focus of increased FLAIR signal (an increased T2 signal, not shown) in the right dorsomedial pons (arrow) ten months after surgery. Comment: Two additional cases have been reported by Eggers et al (1). Patient #2 a 53 year old man and patient #3 a 57 year old man who underwent aortic valve-aneurysm and aortic dissection repair and upon awakening both had lost all saccadic eye movements including optokinetic and vestibular quick phases of nystagmus. As with the 50 year old woman (described above) all other eye movement classes were preserved. Both men had gait ataxia and the 53 year old man also had dysarthria and limb dysmetria. Patient #3, the 57 year old man developed complex partial seizures. The MRI in Patient #2 showed left mesial temporal sclerosis and hippocampal atrophy. The MRI in Patient #3 showed patchy subcortical white matter small vessel changes. The patients were examined 6 to 22 months after surgery with no improvement in the eye movement findings. They all remain unable to read or drive. See also: http://content.lib.utah.edu/cdm/ref/collection/ehsl-shw/id/352