Ocular Bobbing in Association With Other Signs of Midbrain Dysfunction-Reply

In Reply.  —I have seen two patients resembling the one in the interesting case reported by Rosenberg and Calvert. In our patients sudden hemorrhage into the fourth ventricle produced both pontine compression with coma and absent horizontal caloric response, and obstructive hydrocephalus with pretectal compression and pupillary fixation to light. Their downward eye movements resembled ocular bobbing but converged at the nadir. It may be difficult, indeed, in the face of such widespread brainstem damage to assign these abnormal eye movements to the pretectum or pons or perhaps both regions.The patients described with "pretectal pseudobobbing"₁ are distinctly different, however. Clinical involvement was at the pretectum with signs of hypokinetic mutism, upgaze paresis, and abnormal pupillary light reactions. Their pontine tegmentum was functioning well, as evidenced by spontaneous horizontal eye movements and intact facial sensation and movements. The purpose of characterizing pretectal pseudobobbing is to call attention to the surgical emergency