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Biomedical subjects

E Perusquia

Publications and source records attributed to E Perusquia.

3 recordsLinked to original sources

Lightning eye movements.

Physiologic studies were performed on a patient who demonstrated lightning eye movements, palatal myoclonus and myoclonic jerks of the left platysma and sternocleidomastoid muscles. The myoclonus and lightning eye movements were separate phenomena with no defined relationship to each other. Analysis of this ocular dyskinesia identified strictly horizontal saccadic oscillations, 2 to 5 Hz in frequency, with amplitudes varying greatly but often reaching 25 degrees. A brief stationary period between each saccadic oscillation was frequently observed. They were particularly induced by vertical or horizontal ocular pursuit as well as sustained upward or downward ocular deviation. Caloric nystagmus abolished the oscillations but they persisted, irregularly, during optokinetic nystagmus. Thus a faulty visual fixation mechanism is postulated to precipitate lightning eye movements. Constrast studies revealed a mass lesion arising from the right dorsolateral portion of the medulla. These results indicate that lightning eye movements occur with caudal as well as rostral brain-stem lesions. From the clinical findings cerebellar pathway involvement is likely.

Adult

"Saccadic nystagmus" in cerebellar cortical atrophy.

An ocular dyskinesia designated "saccadic nystagmus" was observed in a patient with cerebellar cortical atrophy. Saccadic nystagmus is a sustained ocular dyskinesia present during visual fixation and abolished by eye closure. It is difficult to distinguish visually from either pendular or jerk nystagmus without eye movement recordings. The oscillations are horizontal and rapid and may be influenced by direction of gaze. Caloric nystagmus (eye closed) and optokinetic nystagmus were normal in our patient. Visual fixation abolished caloric nystagmus, which was replaced by saccadic nystagmus.

Caloric Tests