Supranuclear Vertical Gaze Paralysis with Normal Mental Function (Part II)

At this conference last year, we presented a case of total vertical gaze paralysis with normal mental function and postulated that a unilateral mesencephalic lesion produced the disturbance. Recently, we have seen a second similar case who had an associated right hemiparesis, suggesting a leftsided lesion. A day later, the patient developed an internuclear ophthalmoplegia (INO) on leftward gaze, consistent with a rightsided lesion as well. Assuming both of these findings were due to a single lesion, and assuming a mesencephalic locus, one may conclude that discrete bilateral mesencephalic lesions do not necessarily produce coma.