Upbeat and downbeat nystagmus in a single case

Abstract

A 26-year-old woman with neuro-Beh?et disease presented with a primary position upbeat nystagmus which decreased with tilting head. The nystagmus changed upbeat to downbeat with caloric stimulation. When she returned 22 months later, she had less upbeat nystagmus in primary position and had developed a downbeat nystagmus on gaze down. Again, head tilting had an effect on the nystagmus. At this time, the head tilt caused the amplitude of the downbeat nystagmus to increase. Both findings suggest a vestibular component in the patient's difficulty of eye movement, and an otolith-related component in the genesis of upbeat nystagmus.

Key Words:

• upbeat nystagmus
• downbeat nystagmus
• neuro-Behcet disease
• eye movement