Pulse-synchronous pendular nystagmus following cholesteatoma surgery

A 33-year-old woman developed nausea, vertigo, and oscillopsia immediately after surgery for a left ear cholesteatoma. Vertigo increased during Valsalva maneuver. Neurologic examination showed a pulse-synchronous pendular nystagmus (video on the Neurology® Web site at [Neurology.org][1]) and postural imbalance. Cerebral MRI was inconspicuous. CT disclosed a discontinuity of the temporal bone lateral to the left horizontal semicircular canal, compatible with perilymph fistula (figure). After revision surgery, the symptoms disappeared. Acquired pendular nystagmus is a neuro-ophthalmologic finding that is almost exclusively caused by CNS disorders.1 However, occurrence with postsurgical perilymph fistula has been reported.2 Pulse-synchronicity of ocular oscillations may help to identify peripheral causes. [1]: http://neurology.org/lookup/doi/10.1212/WNL.0000000000001710