Wallenberg's syndrome: neurotological classification.

Objective: Visually induced eye movements were investigated in 26 patients with Wallenberg's syndrome.

Methods: Slow-phase optokinetic nystagmus (OKN) velocities, pursuit gains, and percentage fixation suppression (%FS) of caloric nystagmus were recorded by DC electrooculography (EOG), and stored directly onto FM magnetic tape.

Results: OKN velocities, pursuit gains, and %FS decreased toward the lesion side (group A), whereas OKN velocities and pursuit gains decreased toward the side contralateral to the lesion side. %FS decreased toward the lesion side (group B). MR images in group A showed that lesions were only in and near to the vestibular nuclei, and images in group B showed that lesions extended to the cerebellum.

Conclusions: Visually guided eye movements allow classification of Wallenberg's syndrome into two types, one with brainstem lesions and one with both brainstem and cerebellar lesions. This demonstrates that assessing eye movements is helpful in supplementing MRI data.