Oculomotor syndromes PEARLS

cf Tilikete C, Pelisson D. Oculomotor syndromes of the brainstem and cerebellum. Curr Opin Neurol 21:22-28 2008

Head shaking nystagmus (hsn)- usually is a peripheral vestibular lesion. However it can occur in Wallenberg syndrome.

In central positional nystagmus, Dix Hallpike testing induces downbeat nystagmus(DBN). DBN also occurs in floccular disturbance and the gravity dependent component can be suppressed with 3,4 aminopyridine. Other oddball causes of DBN include West Nile virus encephalomyelitis, intrathecal morphine, a particular genetic syndrome of cerebellar ataxia, or another syndrome combining DBN with motor neuronopathy and cerebellar ataxia.