ABSTRACT
Seesaw nystagmus refers to torsional nystagmus with dissociated vertical components. In this disorder, one eye goes up and intorts while the other one descends and extorts. We describe a 40-year-old man who presented with decreased vision due to pendular seesaw nystagmus. Brain MRI showed the empty sella and enlarged pituitary fossa. The delayed and decreased responses of the visual evoked potentials in the ipsilateral occipital lobe with monocular stimulation suggested unequal crossing of the optic pathways as an underlying mechanism.
Subject(s)
Adult , Humans , Brain , Evoked Potentials, Visual , Magnetic Resonance Imaging , Occipital LobeABSTRACT
The authors report jerky seesaw nystagmus, extorsional downbeating in the right eye and intorsional upbeating in the left eye, in a patient with right internuclear ophthalmoplegia (INO). This pattern of nystagmus may occur by disrupting pathways from contralateral posterior and anterior semicircular canals by a lesion in the medial longitudinal fasciculus. Depending on damage to the pathways from contralateral vertical canals, various patterns of dissociated torsional-vertical nystagmus may accompany INO.
Subject(s)
Humans , Ocular Motility Disorders , Semicircular CanalsABSTRACT
The authors report jerky seesaw nystagmus, extorsional downbeating in the ipsilesional eye and intorsional upbeating in the contralesional eye, in a patient with internuclear ophthalmoplegia (INO) from focal pontine lesion. This pattern of nystagmus may occur by disrupting pathways from contralateral posterior and anterior semicircular canals by a lesion in the medial longitudinal fasciculus. Depending on the pathways involved, various patterns of dissociated torsional-vertical nystagmus may accompany INO.