The interplay of eye movements and gait in patients with downbeat nystagmus syndrome

Downbeat nystagmus (DBN) is the most common form of acquired fixation nystagmus. The key symptom is vertical oscillopsia caused by involuntary eye movements. The patients also complain of instability of gait; however, the characteristics of gait disturbance are largely unknown. Gait disturbance could be a result of impaired visual feedback due to the involuntary ocular oscillations. Alternatively, a malfunction of cerebellar locomotor control might be involved, since DBN is considered a vestibulocerebellar disorder. We simultanely investigated gait performance and eye-head coordination of 18 patients with downbe…