Damping of monocular pendular nystagmus with vibration in a patient with multiple sclerosis.

Acquired pendular nystagmus (PN) occurs commonly in multiple sclerosis (MS) and results in a highly disabling oscillopsia that impairs vision. It usually consists of pseudo-sinusoidal oscillations at a single frequency (3-5 Hz) that often briefly stop for a few hundred milliseconds after saccades and blinks. The oscillations are thought to arise from instability in the gaze-holding networks ("neural integrator") in the brainstem and cerebellum.(1,2) Here we describe a patient with monocular PN in whom vibration on the skull from a handheld muscle massager strikingly diminished or stopped her nystagmus.