PEAK VELOCITIES OF SACCADES AND SHORT-LATENCY SACCADES IN PARINAUDS-SYNDROME

Peak velocities of visually elicited saccades and latencies of saccade s have been studied in a patient with a large tumor in the pineal glan d area that exerted compression in the direction of the corpora quadri gemina and underlying structures. Clinically it effected, among other symptoms, a severely impaired vertical upward gaze. Four repeated exam inations were performed from initial radiation therapy to 12 months po st therapy; normal data were derived from ten control subjects. Follow ing therapeutic intervention, upward and downward gaze normalized almo st completely, but peak saccade velocities in vertical directions rema ined markedly reduced. To examine whether the patient could generate s hort latency ''express'' saccades, latencies of horizontal and vertica l eye movements were also measured with a ''gap-paradigm'' which inclu ded a 200 ms gap between peripheral target onset and fixation point of fset. Surprisingly, the amount of ''express'' saccades was significant ly reduced only in the vertical plane.