Visually guided eye movements in patients with Wallenberg's syndrome.

To determine the lesions and the lateralization in patients with Wallenberg's syndrome, visually-guided eye movements were quantitatively analysed and these findings were compared with a lesioned site as revealed by magnetic resonance imaging (MRI). The 8 patients could be clearly classified into two subgroups based on the functional test of eye movements. In 4 patients, optokinetic nystagmus (OKN), pursuit eye movements and fixation-suppression of caloric nystagmus (FS), utilizing the slow phase velocity as a parameter, were impaired toward the lesioned side in the medulla. In the remaining 4 patients, OKN and pursuit eye movements were impaired toward the side contralateral to the lesion, whereas FS toward the lesioned side, indicating a lesion affecting not only the medulla but also the inferior peduncle and/or the cerebellum. Therefore, the functional visually-guided eye movements can provide a useful test battery with which to detect the lesion site in Wallenberg's syndrome.